RU2817170C2 - Indicator release system and detection method - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: group of inventions relates to a device and a method for releasing an indicator into a production well for measuring flow and monitoring inflow profiles in a wellbore during production. Method includes placement of at least one device for output of indicator in production hydrocarbon well in place of inflow. Said at least one indicator discharge device comprises fluid volume and tracer material arranged in said fluid volume. At least one indicator release device is suspended during production to increase concentration of indicator molecules in said volume of fluid medium. Indicator molecules are released from said at least one indicator device into the produced stream. Presence of an indicator downstream of the influx is detected.

EFFECT: high efficiency of producing the indicator.

27 cl, 57 dwg

Description

The present invention relates to a device and method for releasing a tracer into a production well to measure flow and monitor inflow profiles in the wellbore during production. Aspects of the invention include an indicator release device for storing and selectively releasing the indicator, and a method for detecting the indicator.

PREREQUISITES FOR CREATION OF THE INVENTION

Downhole indicators placed in production wells have proven effective in assessing which fluids are flowing in which parts of the well and at what rates. Traditionally, different indicators have been placed in different inflow zones to the well production equipment installed in the well.

Methods for monitoring fluid flow in a well are known, including transient flow-based quantification where individual indicators are placed at different flow zones in the well. The well is shut down for a period of time to allow high concentration tracers to accumulate in selected inflow zones, and then the well is restarted to bring the tracers to the surface. Sampling and concentration analysis of various indicators are used to obtain qualitative and quantitative performance data.

EP 2633152 discloses a method for estimating the influx profile of well fluids (oil, gas or water) into an oil well with inflow locations into the production stream. The method includes placing indicator sources with indicator materials at well levels located downstream, and creating a transition process in the working flow rate of the entire produced flow by stopping the well. The method includes sampling and analysis of samples and, based on the specified concentrations and sampling sequence, as well as well geometry, calculating inflow volumes using flow models.

However, these methods limit the number of possibilities for obtaining these indicators, since shutting down a well is a complex and very expensive operation that requires careful project planning and leads to loss of revenue due to interruption in production.

Another problem with known downhole tracer methods is that due to downhole conditions, there may be pressure fluctuations in the well, which can affect the flow of tracers into the well. This can lead to situations where tracers move upstream or flow into other areas of the formation, known as cross-flow. Crossflow introduces uncertainty and can affect the accuracy of the flow rate analysis.

Tracer injection systems for downhole use are known from US 6840316 B2 and WO 2016/137328 A1, in which an injection unit releases tracer molecules or particles into the flow.

WO 2018/143814 describes a tracer injection system for use in a well, in which at least two injection devices are located in the well at different locations, with the tracers released synchronously, allowing the flow characteristics of the well to be determined.

Disadvantages of the known methods are that tracers are added to the stream in response to a timed release, while control of whether the tracers enter the target fluid or not downhole is limited, and the analysis of the top of the well is subject to some uncertainties. Downhole injection systems have limitations on the number of indicators and the type of indicators that can be stored and released by the injection device.

There are restrictions on the types of indicators that can be used in wells. Tracers must be released at a high concentration to ensure detection at the surface, but also must not deplete quickly and must have a long life in the well.

Another disadvantage is that downhole injection systems are typically deployed using downhole tools, which can obstruct or impede the production flow and affect flow characteristics measurements. Downhole tools can also become stuck in the hole, requiring costly retrieval operations.

SUMMARY OF THE INVENTION

One of the objects and objects of the invention is to provide a method for monitoring the flow of fluid to a tracer in a hydrocarbon production well by detecting the presence of a tracer that is selectively released into the well's production stream.

Another object of the present invention is to provide a tracer release apparatus for selectively releasing tracer into a production stream so that measurement profiles of flow parameters and inflow into a wellbore can be calculated and controlled.

It is yet another object of the present invention to provide a tracer release device that is capable of producing a high concentration of tracer and selectively releasing high concentration tracers without requiring well shutdown. A high concentration of indicator is detected downstream of the indicator release device.

Another object of an aspect of the invention is to provide a tracer release device that is capable of releasing a high concentration of tracer into the production stream in the form of a tracer cloud that can be detected at the surface, but also controls the exposure of the tracer source to the produced fluid to extend the life of the tracer in the well.

It is yet another object of one aspect of the invention to provide a method and apparatus for selectively releasing a high concentration of tracer that can be detected by real-time sampling and/or analysis methods.

Another object of the invention is to provide a tracer release device that releases tracer in a controlled manner to control the production flow at the surface.

Further objects and objects of the invention will become apparent from the following description.

In accordance with a first aspect of the invention, there is provided a method for monitoring fluid inflow into a hydrocarbon production well, comprising:

installing at least one indicator release device connected to the production string in the hydrocarbon production well at an inflow location, wherein the indicator release device comprises:

a volume of fluid, at least one indicator material located in said volume of fluid, at least one outlet into said volume of fluid, and at least one controllable valve configured to selectively control the flow of fluid through said at least one outlet,

wherein the indicator release device has a first state in which said at least one controllable valve is closed to substantially or completely prevent the passage of fluid and indicator from said volume of fluid into the produced fluid through said at least one outlet, and a second state in which said at least one controllable valve is open to allow fluid and indicator to pass from said volume of fluid into the production string through said at least one outlet,

the method includes:

- production of hydrocarbons from the well using a device for releasing the indicator in its first state at the first flow rate of the produced flow in the production string,

- changing the flow rate of the production stream in the production string to a second flow rate of the production stream to operate said at least one controllable valve to cause fluid and tracer to flow from said volume of fluid into the production string, creating an increased concentration of tracer in the production string,

- detection of the presence of an indicator downstream from the inflow point.

By providing the indicator release device with at least one valve configured to selectively control the flow of fluid through the at least one outlet, it is possible to suspend the device to increase the concentration of indicator molecules in the fluid volume of the device. Subsequently opening the valve to release a higher concentration of indicator may cause an indicator transient. The increased concentration of tracer molecules travels downstream with the production stream as a cloud, slug, or charge of tracer that can be detected downstream of the device and/or at the wellhead as a tracer response signal or peak at the downstream detection point.

The transient processes of the indicator are caused by the velocity field in the well. The appearance of various indicators at the wellhead or the complete transient process of various indicators can be used to estimate the velocity field in the well. Using the velocity field, the inflow profile can be calculated.

The method may include sampling the produced stream. Sampling can be performed one or more times. Sampling can be done downstream of the tracer release device or at the surface. Samples can be collected for later analysis. The method may include estimating or calculating an influx profile based on the concentration and type of tracer as a function of sampling time.

Based on the measured tracer concentrations, their sampling sequence, and well geometry, influx volumes can be calculated. Inflow volumes can be calculated from transient flow models. Inflow volumes can be used to estimate a well's inflow profile.

The method may include detecting the presence of an indicator in the production stream in real time downstream of the inflow location. The method may include monitoring the influx of fluid into a hydrocarbon production well in real time.

The method may include performing optical monitoring to detect indicators in the production stream. The method may include determining the type of indicator. The method may include measuring and/or monitoring the concentration of the indicator.

The method may include analyzing tracer release characteristics, sampling times, and/or cumulative volume produced from influent volumes from various influent zones.

The method may include analyzing the arrival of concentration peaks of each indicator to determine the percentage of influx that occurs between the locations of the indicators. The method may include analyzing the rate of decline of the tracer concentration from each tracer location to determine the percentage of formation inflow from each inflow zone.

The method may include detecting the presence of tracer material at the detection site. The detection location may be a location in the well, or may be a location at the surface, or may be located toward the surface of the production well.

The method may include modeling flow rates in a model well. The modeled influx profile and/or rates can be adjusted until the calculated concentrations of the model indicators compare with the measured concentrations of the identified indicators to estimate the influx profile.

The method may include changing the flow rate of the production stream in the production string to a third flow rate of the production stream to operate a controllable valve to prevent the passage of fluid and tracer material from the specified volume of fluid into the production fluid through the outlet.

The second flow rate of the produced stream may be higher than the first flow rate of the produced stream. Alternatively, the second flow rate of the production stream may be lower than the first flow rate of the production stream. The third flow rate of the produced stream may be higher than the second flow rate of the produced stream. Alternatively, the third production stream flow rate may be lower than the second production stream flow rate.

Preferably, the indicator release device has at least one inlet into said volume of fluid.

The method may include operating said at least one controllable valve to open said at least one inlet and/or at least one outlet. The method may include operating said at least one controllable valve to close the inlet and/or outlet. Said at least one controllable valve may be located in said at least one outlet between said volume of fluid and the production string. Said at least one controllable valve may be located in said at least one inlet between said volume of fluid and the production string.

The device may comprise a first controllable valve located at an outlet between said volume of fluid and the production string, and a second controllable valve located at an inlet between said volume of fluid and the production string. The method may include operating a controllable valve to open the inlet and/or outlet. The method may include operating a controllable valve to close the inlet and/or outlet.

The first, second and third costs of the produced flow may be non-zero. At least one of the first, second and/or third flow rates of the produced stream may be zero. The flow rate of the produced stream can be changed using a throttle connected to the production string. The choke can be underwater or land-based. The choke may be a downhole choke.

The third flow rate of the production stream may be substantially the same as the first flow rate of the production stream. Thus, the controllable valve can be actuated to open by temporarily changing the flow rate of the production stream to a higher or lower flow rate of the production stream.

The indicator release device may have a third state in which said at least one controllable valve is in a position intermediate between a fully open position and a fully closed position to throttle the flow of fluid and indicator materials passing from said volume of fluid into the production string. through the outlet.

By providing a device capable of controlling the accumulation and selective release of a high concentration of tracer, the detectable level of tracer can be controlled downstream as needed.

The method may include closing a valve of the at least one indicator release device for a certain period of time to suspend the indicator release device. When the indicator release device is suspended, the concentration of indicator particles or molecules released into a specified volume of fluid or flow channel of the indicator release device increases until the volume of fluid in the flow channel is enriched or saturated with indicator particles.

The method may include pausing the device to release the indicator for a certain period of time. The time period can vary from hours to months.

The method may include closing the valve for less than 24 hours to pause the device to release the indicator. The method may include closing the valve for more than 24 hours to pause the device to release the indicator. The method may include opening a valve to release fluid and tracer particles or molecules from the flow channel through the outlet into the production stream.

The method may also include controlling the exposure of the tracer material to the produced flow to extend the life of the downhole tracer material. When the indicator release device is paused, indicator molecules may be released into the fluid volume of the device until the fluid volume becomes enriched or saturated with indicator molecules. Once the fluid volume is enriched or saturated with indicator molecules, the release of the indicator into the fluid volume may be largely or completely stopped.

This method may also provide the ability to use tracer systems that were previously considered unsuitable due to the high flow rate of release from the tracer source into the target fluid under downhole conditions. In fact, the high release rate of such tracers may enable the creation of high concentrations of tracers in a short period of time. This can be useful when flow indicator operations need to be performed in quick succession.

In accordance with a second aspect of the invention, there is provided a method for monitoring fluid inflow into a hydrocarbon production well in real time, comprising:

- installing at least one indicator release device connected to the production string in the producing hydrocarbon well at the inflow location, wherein the indicator release device comprises:

fluid volume,

at least one indicator material located in the specified volume of fluid,

at least one outlet into said volume of fluid,

and a controllable valve configured to selectively control the flow of fluid through the outlet,

wherein the indicator release device has a first state in which said at least one controllable valve is closed to substantially or completely prevent the passage of fluid and indicator from said volume of fluid into the produced fluid through the outlet, and a second state in which said at least one controllable valve is open to allow fluid and indicator to pass from said volume of fluid into the production string through an outlet, the method comprising:

- production of hydrocarbons from the well using a device for releasing the indicator in its first state at the first flow rate of the produced flow in the production string,

- changing the flow rate of the production stream in the production string to a second flow rate of the production stream to operate a controllable valve to cause fluid and tracer to flow from the specified volume of fluid into the production string, creating an increased concentration of tracer material in the production string,

- detection of the presence of an indicator downstream from the inflow point.

The method may include detecting the presence of an indicator at a detection location. The detection location may be a location in the well, or may be a location at the surface, or may be a location toward the surface of the production well.

The method may include changing the flow rate of the production stream in the production string to a third flow rate of the production stream to actuate the at least one controllable valve to close the outlet and substantially or completely prevent the passage of fluid and indicator material from the specified volume of fluid into the production fluid. through the outlet.

The method may include optical detection of the indicator. The method may include emitting light from a light source into a production stream. The method may include producing light created by luminescence inherent in indicators present in the stream. The method may include collecting and analyzing the backscatter light signal. The method may include transporting a produced stream from tracer release locations in a well to a real-time sensor in the produced stream at a detection point downstream of the tracer release device.

The method may include performing optical monitoring to detect indicators in the production stream. The method may include determining the type of indicator. The method may include measuring and/or monitoring the concentration of the indicator. The method may include tracking the arrival time of the indicator.

Detection can be accomplished by monitoring at a detection point inside the well. Monitoring may also or instead be performed at a detection point at the wellhead.

The method may include monitoring with detection equipment and/or real-time detection, in-line detection, delayed measurement, or the like. Such monitoring may be more or less continuous and will pick up or detect indicator signals whenever they occur. Monitoring can be accomplished by analyzing collected or subsampled fluid samples. This may require releasing the indicator at a scheduled time or using an automatic sampling device, as manual sampling can be resource intensive.

Said at least one controllable valve may be located in an outlet between said volume of fluid and the production string. Said at least one controllable valve may be located in an inlet between said volume of fluid and the production string. Controllable valves may be located at the inlet and outlet between the specified volume of fluid and the production string.

The indicator material may be configured to selectively release indicator molecules from the indicator material into a fluid in the indicator chamber upon contact with a particular well fluid. The indicator material may be configured to release indicator molecules from the indicator material into a fluid in the indicator chamber upon contact with a target well fluid.

Preferably, the indicator material is configured to release indicator molecules into the indicator chamber when the indicator material is exposed to a target fluid, ie oil, gas or water. The indicator material may be solid, liquid or gas.

The indicator material may be selected from the group consisting of chemical, fluorescent, phosphorescent, magnetic, DNA and/or radioactive compounds.

The indicator material may contain chemical indicators selected from the group consisting of perfluorinated hydrocarbons or perfluoroethers.

Perfluorinated hydrocarbons can be selected from the group consisting of perfluorobutane (PB), perfluoromethylcyclopentane (PMCP) and/or perfluoromethylcyclohexane (PMCH). The indicator material may contain a dye. The indicator material may contain a luminescent dye.

Embodiments of the second aspect of the invention may include one or more features of the first aspect of the invention or embodiments thereof, or vice versa.

In accordance with a third aspect of the invention, there is provided a method for monitoring fluid inflow into a hydrocarbon production well in real time, comprising:

installing at least one indicator release device connected to the production string in a hydrocarbon production well at an inflow location, wherein the indicator release device comprises:

fluid volume,

at least one indicator material located in the specified volume of fluid,

at least one outlet into said volume of fluid, and

at least one controllable valve located in said at least one outlet between said volume of fluid and the production string,

wherein said at least one indicator release device has a first state in which said at least one controllable valve is closed to substantially or completely prevent the passage of fluid and indicator from the fluid volume into the produced fluid through said at least one an outlet, and a second state in which said at least one controllable valve is open to allow fluid and indicator to pass from the fluid volume into the production string through said at least one outlet,

the method includes:

- production of hydrocarbons from the well using said at least one device for releasing the indicator in its first state at the first flow rate of the produced stream in the production string,

- changing the flow rate of the production stream in the production string to a second flow rate of the production stream to actuate the controllable valve to open the outlet and cause fluid and tracer material from the specified volume of fluid to flow into the production string, creating an increased concentration of tracer in the production string,

- detection of the presence of an indicator downstream from the inflow point at the detection point towards the surface of the production well.

The method may include optical detection of the indicator. The method may include emitting light from a light source into a production stream. The method may include producing light created by luminescence inherent in indicators present in the stream. The method may include collecting and analyzing the backscatter light signal.

The method may include allowing the production stream to be transported from tracer release locations in the well to a sensor in real time in the production stream at a detection point downstream of the tracer release device.

The method may include performing optical monitoring to detect indicators in the production stream. The method may include determining the type of indicator. The method may include monitoring the concentration of the indicator. The method may include tracking the arrival time of the indicator.

Embodiments of the third aspect of the invention may include one or more features of the first or second aspect of the invention or embodiments thereof, or vice versa.

In accordance with a fourth aspect of the invention, there is provided a method for monitoring fluid inflow into a hydrocarbon production well, comprising:

installing two or more tracer release devices connected to the production string in a hydrocarbon production well, wherein the tracer release devices are located at different locations in the inflow,

the device for releasing the indicator contains:

fluid volume,

at least one indicator material located in the specified volume of fluid,

at least one outlet into said volume of fluid, and

at least one controllable valve configured to selectively control the flow of fluid through said at least one outlet,

wherein each tracer release device has a first state in which said at least one controllable valve is closed to substantially or completely prevent the passage of fluid and tracer from said volume of fluid into the produced fluid through said at least one outlet, and a second state in which said at least one controllable valve is open to allow fluid and indicator to pass from said volume of fluid into the production string through said at least one outlet,

the method includes:

- production of hydrocarbons from the well using a device for releasing the indicator in its first state at the first flow rate of the produced flow in the production string,

- changing the flow rate of the production stream in the production string to a second flow rate of the production stream to operate said at least one controllable valve to cause fluid and tracer to flow from said volume of fluid into the production string, creating an increased concentration of tracer in the production string,

- detection of the presence of an indicator downstream from the inflow point at the detection point in the direction towards the surface of the production well.

The method may include sampling the produced stream. Sampling may be performed at one or more of the specified sampling times. Sampling can be done downstream of the tracer release device or at the surface. Samples can be collected for later analysis.

The method may include monitoring the influx of fluid into a hydrocarbon production well in real time.

The method may include performing optical monitoring to detect indicators in the production stream. The method may include determining the type and/or concentration of the indicator. The method may include monitoring the concentration of the indicator. The method may include tracking the arrival time of the indicator.

The method may include analyzing tracer release characteristics, sampling times, and/or cumulative volume produced from influent volumes from different influent zones.

The method may include analyzing the arrival of concentration peaks of each indicator to determine the percentage of influx that occurs between the locations of the indicators. The method may include analyzing the rate of decline of the tracer concentration from each tracer location and/or tracer release device location to determine the percentage of formation inflow from each inflow zone.

The method may include calculating or estimating an influx profile based on the type of indicator and measured concentrations of the indicator. The method may include using the calculated or estimated inflow profile as parameters to control production flow or to characterize the formation.

The method may include modeling flow rates in a model well. The modeled influx profile and/or flow rates can be adjusted until the calculated concentrations of the model indicators compare with the measured concentrations of the identified indicators to estimate the influx profile.

The method may include optical detection of the indicator.

The method may include releasing a high concentration of tracer from each device to release the tracer into a local production stream substantially simultaneously. The method may include releasing a high concentration of tracer from each device to release the tracer into a local production stream in an alternating order or sequentially.

The method may include measuring a tracer concentration and estimating an influx profile based on the type of tracer, measured tracer concentrations and tracer release characteristics, sampling times, and/or cumulative volume produced from influx volumes from different influx zones.

The method may include actuating the valve in response to a pressure difference between the fluid volume and the production string.

The method may include actuating the valve in response to a change in the flow rate of the produced stream.

Embodiments of the fourth aspect of the invention may include any of the features of the first to third aspects of the invention or embodiments thereof, or vice versa.

In accordance with a fifth aspect of the invention, there is provided a tracer release system for monitoring the influx of fluid into a production oil well containing

at least one indicator release device for connection to the production string, wherein said at least one indicator release device comprises

at least one outlet,

at least one indicator chamber in fluid communication with said at least one outlet,

indicator material located in the indicator chamber, and

at least one valve configured to selectively control the flow of fluid through said at least one outlet.

Said at least one indicator release device may comprise at least one inlet hole. Said at least one inlet opening may be in fluid communication with said at least one indicator chamber. The at least one valve may be configured to selectively control the flow of fluid through the at least one inlet. The at least one valve may be configured to selectively open and close the at least one inlet and/or outlet to control the flow of fluid through the at least one inlet and/or outlet.

The at least one valve may be configured to selectively open and close the at least one inlet between a fully open position, a fully closed position, or an intermediate position between a fully open and fully closed position.

The at least one valve may be configured to selectively open and close the at least one outlet between a fully open position, a fully closed position, or an intermediate position between a fully open and fully closed position.

The at least one valve may operate to control the flow and change the opening area of the openings to allow flow to flow through the at least one inlet and/or through the at least one outlet.

The indicator material may be configured to selectively release indicator molecules from the indicator material into a fluid into the indicator chamber upon contact with a particular well fluid.

Preferably, the indicator material is configured to release indicator molecules into the indicator chamber when the indicator material is exposed to a target fluid, ie oil, gas or water. The indicator material may be solid, liquid or gas.

The indicator material can be selected from the group including chemical, fluorescent, phosphorescent, magnetic, DNA and radioactive compounds.

The indicator material may contain chemical indicators selected from the group consisting of perfluorinated hydrocarbons or perfluoroethers.

Perfluorinated hydrocarbons can be selected from the group consisting of perfluorobutane (PB), perfluoromethylcyclopentane (PMCP) and/or perfluoromethylcyclohexane (PMCH).

The indicator material may contain a luminescent dye. The indicator material may be chemically immobilized within the indicator chamber.

The indicator material may comprise an indicator and a carrier. The carrier may be a matrix material. The matrix material may be a polymeric material.

The indicator may be chemically immobilized in the carrier. The indicator material can be chemically immobilized through chemical interaction between the indicator and the carrier. The indicator material can be chemically immobilized such that it releases indicator molecules or particles in the presence of a chemical trigger. By varying the chemical interaction between the indicator and the polymer release mechanism, the rate at which indicator molecules are released from the indicator material can be controlled. Preferably, the indicator is released from the indicator carrier at a uniform release rate.

The carrier may be selected from polymethyl methacrylates (PMMA), polymethyl acrylates, polyethylene glycols (PEG), polylactic acid (PLA) or polyglycolic acid (PGA), commercially available polymers or copolymers thereof.

The carrier may be selected from polymers with higher indicator release rates, such as polyethylene and polypropylene.

The indicator material may be physically dispersed and/or physically encapsulated in the carrier.

The indicator material may release indicator molecules into the fluid as a result of dissolution or decomposition of the carrier and/or indicator in the fluid.

The carrier may be selected to provide controlled degradation upon contact with a fluid. The carrier may be selected to ensure degradation by hydrolysis of the carrier.

The indicator material and/or carrier may be specific to the fluid such that indicator molecules will be released from the indicator material in response to contact with the target fluid.

The indicator material and/or carrier may be chemically intelligent such that indicator molecules will be released from the indicator material in response to certain events, for example, they react to the flow of oil (oil-bearing) but do not respond to the flow of water (water-resistant). In the same area, another group of chemical compounds can be placed that release indicators in the flow of water (water-active), but do not react to the flow of oil (oil-resistant). The indicators and/or carrier may be chemically intelligent such that indicator molecules will be released from the indicator material in response to the influence of the indicator material on the wellbore fluid and/or the target wellbore fluid.

The indicator can be detected and its concentration can be measured using various methods, such as optical detection, optical fibers, spectrophotometric methods, PCR methods combined with sequential analysis, chromatographic methods or radioactive analysis. The invention is not limited to the above-mentioned technologies.

The indicator can be detected and its concentration can be measured by sampling the produced fluid. Sampling can be done using a sampler placed in the production stream. The sampler can be located inside the well or on the surface. Sampling may occur at one or more of the specified sampling times. Sampling may be carried out downstream of the tracer release device or at the surface. Samples may be collected for later analysis.

The indicator may be detected by a detection device such as a sensor. The detection device may facilitate monitoring and/or analysis of the tracer in the produced fluid in real time. Real-time monitoring and/or analysis may be performed by the sensor probe. The sensor probe may be placed in the production stream. The sensor probe can be located in the borehole or on the surface.

The indicator material may be located in the indicator chamber to allow the fluid to contact the indicator material as it passes around the indicator material in the indicator chamber.

The at least one valve may be an electrically actuated valve, a mechanical valve and/or a thermodynamic valve. The at least one valve may be configured to selectively open and/or close in response to an event in the well.

The at least one valve may be configured to selectively open and/or close in response to changes in temperature, pressure and/or speed. The at least one valve may be configured to selectively open and/or close in response to the at least one electronic signal.

The at least one valve may be a pressure difference controlled valve. The at least one valve may be configured to selectively open and/or close in response to a pressure difference across the valve.

The at least one valve may be configured to selectively open and/or close in response to changes in fluid pressure in the well. The at least one valve may be configured to selectively open and/or close in response to a pressure difference between the at least one inlet and the at least one outlet. The at least one valve may be configured to selectively open and/or close in response to a pressure difference between the indicator release device and the production string. The at least one valve may be configured to selectively open and/or close in response to a pressure difference between the fluid volume and the production string.

Said at least one valve may be a kinematic valve. The at least one valve may be configured to selectively open and/or close in response to changes in fluid flow rate in the production stream.

The at least one valve may be an electrically actuated valve. The at least one valve may be configured to selectively open and/or close in response to receipt of at least one electrical or electronic signal. The at least one valve may be wired or wireless controlled. The signal to control actuation of the valve may come from a surface or other external source. The at least one valve may comprise or be connected to a wireless communication system. The wireless communication system may include at least one wireless receiver capable of receiving data via wireless communication to control and actuate the electrically actuated valve. The wireless communication system may include at least one transmitter for transmitting a signal.

The at least one valve may be configured to selectively open and/or close in response to a transient in the flow of the produced stream. The transient may be a temporary transient in the flow rate of the produced stream.

The at least one valve may be set as normally open or normally closed. Said at least one valve may be a flap valve or a spool valve. The at least one valve can be configurably set to be normally open or normally closed. Preferably, said at least one valve is configured to respond to the velocity or pressure of a fluid in the well.

The at least one valve may be configured to open and/or close at a predetermined flow rate or predetermined fluid flow pressure. The valve may be configured to have at least one actuation threshold level.

Said at least one valve may be installed to be partially open and/or partially closed. The valve may be configured to open and/or close in positions intermediate between a fully open position and a fully closed position.

The at least one valve may be configured to open and close in positions intermediate between a fully open position and a fully closed position to selectively control the flow of fluid through the at least one outlet.

Said at least one valve may comprise a bias mechanism. The at least one valve may be balanced or biased by a bias mechanism that is configured to set the valve at a predetermined fluid velocity or fluid pressure level that must be achieved before the valve is actuated. The bias mechanism may be a spring. The bias mechanism may be a coil spring, a leaf spring, or a gas spring such as a nitrogen spring.

The bias mechanism can be adjusted to set the valve actuation threshold. Preferably, the valve is pressed by a spring, which can be adjusted by changing the type, length or tension of the spring. The valve actuation threshold can be set.

The at least one indicator release device can be retrofitted for installation in an existing column. The at least one indicator release device can be removed, installed, replaced and/or adjusted using a cable, wire rope, coiled tubing, drill pipe or similar means of transportation.

The at least one indicator release device may be installed or replaced and may be transported along the production string by wireline, wireline, coiled tubing, drill pipe, or similar means of transportation. The at least one indicator release device can be moved onto at least one landing nipple. Said at least one landing nipple may have holes communicating with the production casing and/or with the annulus.

The at least one tracer release device or a component of the at least one tracer release device may be installed or replaced and may be transported along the production string by wireline, wireline, coiled tubing, drill pipe or similar means of transportation. .

The at least one valve may be installed in an existing indicator release device located in the well. Said at least one valve can be removed, installed, replaced and/or adjusted using a cable, wire rope, coiled tubing, drill pipe or similar means of transportation.

The at least one valve may be installed or replaced and may be transported along the production string using wireline, wireline, coiled tubing, drill pipe or similar means of transportation. Said at least one valve can be moved by at least one landing nipple. Said at least one landing nipple may have holes communicating with the production casing and/or with the annulus.

The settings of the at least one valve can be adjusted by directly connecting to the valve from the surface. The valve settings may be adjusted through an intervention operation by lowering the intervention device using a cable, wireline, coiled tubing, drill pipe, or similar conveying means to control and adjust the setting of the at least one valve.

The indicator release device may comprise at least one flow limiting device. Said at least one flow limiting device may be located in the indicator chamber. The at least one flow restriction device may be located in the at least one inlet and/or in the at least one outlet.

The at least one flow restriction device may be selected from the group consisting of a nozzle, an orifice, a Venturi tube, a pitot tube, or a deflection path.

The at least one flow limiting device may be configured to control the release of indicator molecules from the indicator chamber of the indicator release device into the production string. The at least one flow limiting device can be adjusted to vary the rate of release of indicator molecules from the indicator chamber.

The at least one flow limiting device can be adjusted to change the release of the indicator and adjust the amplitude and/or duration of the peak response of the indicator at the point of detection. The release of the tracer from the tracer release device into the production string can be delayed or prolonged by using a flow restriction device. Increasing the resistance of the flow limiting device to the fluid flow passing through it leads to an increase in the washout time of the indicator.

The release of the indicator from the indicator release device may produce a characteristic signal called a washout signal. The washout signal has a concentration peak followed by a concentration decline. The decline in concentration after a peak can be expressed by a slowly decreasing function, such as an exponential function or a power function. The coefficient in the slope functions is proportional to the velocity of the fluid within the indicator release device, and thus the velocity of the fluid within the indicator release device can be calculated based on the measured decay curve of the indicator concentration. A steeper curve, ie shorter washout time, corresponds to a higher fluid velocity within the indicator release device.

The duration of the indicator signal can be determined by sampling or real-time measurement. The signal must be long enough so that it is not destroyed by scattering as it travels to the detection point, which may be located behind the top well production equipment and liner extension. The output and dispersion of indicators can be modeled using flow models. Signal dispersion during movement to the detection point can be compensated for by modeling based on the well geometry and/or the well model.

The indicator release device may comprise at least one inlet valve. The at least one inlet can control the flow of fluid through the at least one inlet. The indicator release device may comprise a release valve for controlling the flow of fluid through the at least one outlet. The at least one inlet and/or outlet may be configured to control the release of indicator molecules from the indicator chamber of the indicator release device into the production string. The at least one inlet and/or outlet may act as a limiting device and may be adjustable to change the rate of release of indicator molecules from the indicator chamber.

Said at least one inlet valve and said at least one exhaust valve may be configured to operate independently of each other. The at least one inlet valve and the at least one outlet valve may be configured to operate in cooperation with each other. The at least one inlet valve and the at least one outlet valve may be configured such that one valve operates as a main valve and the other valve operates as a secondary valve, such that the secondary valve imitates the actions and reactions of the main valve.

Said at least one inlet and/or said at least one outlet may be in fluid communication with the production string. Said at least one inlet and/or said at least one outlet may be in fluid communication with the annulus. The production string may be an internal pipe into which the production fluid enters the production zone. The production string may extend from the downhole space to the surface.

The indicator release system may contain two or more indicator release devices. These two or more indicator release devices may be configured to be connected to the production string at various positions along the production string. The indicator release device may be located downstream of the inflow zone. Each indicator chamber of a corresponding indicator release device may contain a separate indicator material.

Embodiments of the fifth aspect of the invention may include any features of the first to fourth aspects of the invention or embodiments thereof, or vice versa.

In accordance with a sixth aspect of the invention, there is provided a method of releasing an indicator into a production stream, comprising:

installing at least one indicator release device connected to the production string, wherein said at least one indicator release device comprises:

at least one fluid outlet, at least one indicator chamber in fluid communication with the at least one outlet, indicator material located in the indicator chamber, at least one valve configured to selectively control the flow of fluid through said at least one outlet, and

opening said at least one valve and releasing the indicator from the flow channel and through said at least one outlet.

Said at least one outlet hole may be in fluid communication with the produced stream. The at least one indicator release device may comprise at least one inlet in fluid communication with the produced stream. Said at least one indicator chamber is in flow communication with said at least one inlet. The at least one valve is configured to selectively control the flow of fluid through the at least one inlet.

The method may include opening and/or closing the at least one valve in response to a change in fluid velocity or fluid pressure in the well. The method may include opening and/or closing a valve in response to a pressure difference between said at least one inlet and said at least one outlet. The method may include opening and/or closing a valve in response to a pressure difference between the indicator chamber and the production string.

The method may include creating a pressure difference between said at least one inlet and said at least one outlet. A pressure difference can be created by adjusting the flow rate of the produced stream.

The method may include controlled setting of at least one threshold fluid flow rate or pressure level to operate the valve to selectively open and/or close the at least one outlet.

The method may include opening said at least one valve to a position intermediate between a fully open and fully closed position.

The method may include closing said at least one valve for a period of time to close the indicator chamber and increase the concentration of indicator particles or molecules released into the flow channel and/or volume of fluid. Said at least one valve may be closed for less than 24 hours to suspend the indicator chamber. The valve may be closed for more than 24 hours to close the indicator chamber. By high or elevated concentration is meant an increased concentration of tracer molecules compared to the concentration of tracer molecules present in the well fluid that was not interrupted by the tracer release device.

The method may include opening a valve to release fluid and indicator molecules from the indicator chamber through the at least one outlet into the production stream. The method may include releasing indicator molecules from the indicator chamber by flushing the flow channel with a produced fluid entering the flow channel.

The method may include adjusting the flow rate of the produced stream to control the flow rate of the fluid acting on the at least one valve. The method may include increasing the flow rate of the produced stream to create a pressure difference between the at least one inlet and the at least one outlet to close or open the at least one valve.

The method may include reducing the flow rate of the produced stream to create a pressure difference between the at least one inlet and the at least one outlet to close or open the valve.

The method may include restricting flow from the display chamber to the production string. The method may include restricting flow through the display chamber to control and/or delay the release of fluid from the display chamber into the production string.

The method may include releasing the tracer at a concentration such that it can be detected downstream by sampling and/or real-time methods.

Embodiments of the sixth aspect of the invention may include any of the features of the first to fifth aspects of the invention or embodiments thereof, or vice versa.

In accordance with a seventh aspect of the invention, there is provided a method for estimating the inflow profile of at least one of the downhole fluids into a production well with two or more inflow zones into the production stream, comprising:

placing two or more tracer release devices connected to the production string at known well levels,

each device for releasing the indicator contains: at least one outlet,

at least one indicator chamber in fluid communication with said at least one outlet,

a separate indicator material located in the at least one indicator chamber, and

at least one valve configured to selectively control the flow of fluid through said at least one outlet,

opening said at least one valve to release indicator molecules from the indicator chamber into the production stream through said at least one outlet,

measuring an indicator concentration and estimating a flow profile for at least one of the well fluids based on the type of indicator and the measured indicator concentrations.

Said at least one outlet hole may be in fluid communication with the produced stream. The at least one indicator release device may comprise at least one inlet in fluid communication with the produced stream. Said at least one indicator chamber is in flow communication with said at least one inlet. The at least one valve is configured to selectively control the flow of fluid through the at least one inlet.

Downhole fluids may be oil, water and/or gas. Each tracer release device may be connected to the production string at different locations in the inflow zone. By installing tracer release devices in inflow zones, the contribution of each individual zone to the overall well production can be monitored, assessed and/or calculated.

The method may include analyzing the characteristics of tracer release, sampling time, and/or cumulative volume produced of influent volumes from different influent zones.

The method may include closing a valve on the at least one indicator release device for a certain period of time to suspend the indicator release device. When the indicator release device is paused, the concentration of indicator particles or molecules released into the flow channel increases until the volume of fluid in the flow channel becomes saturated with indicator particles.

The method may include closing the at least one valve for a period of time sufficient to create a high concentration of tracer molecules that can be detected as a high amplitude tracer response signal at a downstream detection point when the tracer particles or molecules are released from the tracer release device.

The method may include pausing the device to release the indicator for a certain period of time. The time period can vary from hours to months.

The method may include closing the valve for less than 24 hours to pause the device to release the indicator. The method may include closing the valve for more than 24 hours to pause the device to release the indicator. The method may include closing the valve to restrict access to or exposure of the indicator material to the produced flow.

The method may include opening a valve to release fluid and tracer particles or molecules from the flow channel or fluid volume of the device to release the tracer through the outlet into the production stream.

The method may include opening the valve by adjusting the fluid velocity and/or fluid pressure in the production string. The method may include closing the valve by adjusting the fluid velocity and/or fluid pressure in the production string.

The method may include opening a valve in response to a pressure difference between said at least one inlet and said at least one outlet. The method may include opening and/or closing a valve in response to a pressure difference between the flow channel and the production string.

The pressure difference can be created by regulating the flow rate of the produced stream.

The method may include opening valves on each of two or more tracer release devices at substantially the same time to release tracer molecules into the production stream.

The method may include controlled adjustment of the valve to operate above or below a predetermined threshold or flow rate range of the produced stream. The method may include controlled adjustment of the valve to operate at a plurality of predetermined thresholds or flow ranges of the production stream.

The method may include releasing indicator particles or molecules from a flow channel of each indicator release device by means of a production fluid entering the channel and flushing the indicator molecules from the channel.

The method may include adjusting the flow rate of the production stream to create a pressure difference to close the valve after the tracer molecules have been flushed from the tracer release device.

The method may include controlling and/or delaying the release of fluid from the tracer release device into the production string by limiting the flow from the tracer release device into the production string.

The method may include sampling a well fluid downstream of the tracer release device. Samples may be taken from the surface.

Wellbore fluid samples are collected at the surface and the concentration of the indicator in the wellbore fluid is measured. Samples can be collected and/or measured downstream at a known sampling time. The influx volume can be calculated based on the measured concentrations and their sampling sequence and well geometry. The method may include estimating or calculating an influx profile based on the concentration and type of tracer as a function of sampling time. Inflow volumes can be calculated from transient flow models. Inflow volumes can be used to estimate a well's inflow profile.

The method may include generating at least one detectable tracer peak at a detection point downstream of the tracer release device.

The method may include analyzing tracer release characteristics, sampling times, and/or cumulative volume produced from influx volumes from different influx zones. The method may include analyzing the arrival of concentration peaks of each indicator to determine the percentage of influx that occurs between the locations of the indicators. The method may include analyzing the rate of decline of the tracer concentration from each tracer location and/or tracer release device location to determine the percentage of formation inflow from each inflow zone.

The method may include using the calculated inflow profile as parameters to control production flow or to characterize the formation. The method may include modeling flow rates in a model well. The modeled influx profile and/or flow rates can be adjusted until the calculated concentrations of the model indicators compare with the measured concentrations of the identified indicators to estimate the influx profile.

Embodiments of the seventh aspect of the invention may include any of the features of the first through sixth aspects of the invention or embodiments thereof, or vice versa.

In accordance with an eighth aspect of the invention, there is provided a method for monitoring fluid inflow into a hydrocarbon production well, comprising:

installing at least one indicator release device in a hydrocarbon production well at an inflow location, wherein said at least one indicator release device comprises: a volume of fluid and

indicator material located in the specified volume of fluid,

suspending the indicator release device to create a high concentration of indicator molecules in the specified volume of fluid,

releasing high concentration indicator molecules from the indicator release device into the production stream, and

detecting the presence of an indicator downstream of the inflow location.

The method may include pausing the device to release the tracer while the well is producing. The method may include pausing the tracer release device to limit or prevent exposure of the tracer material to the production stream. The method may include pausing the device to release the indicator at the first flow rate of the production stream. The method may include releasing a high concentration of indicator molecules from the indicator release device at a second production flow rate.

Said at least one indicator release device may comprise at least one controllable valve. The at least one controllable valve may be configured to suspend the indicator release device to allow the concentration of indicator molecules in the volume of fluid in the indicator chamber to increase or accumulate. This may allow indicator molecules to accumulate locally in the fluid in the indicator chamber, forming an indicator cloud that can be flushed out when the valve is opened.

The at least one controllable valve may be configured to control the flow of fluid through the outlet of the at least one indicator release device. The method may include changing the flow rate of a production stream in a production string to actuate said at least one controllable valve to suspend the tracer release device and/or release high concentration tracer molecules from the tracer release device.

The method may include sampling the produced stream, wherein sampling is carried out at said one or more sampling periods.

The method may include monitoring the influx of fluid into a hydrocarbon production well in real time. The method may include performing optical monitoring to detect indicators in the production stream.

The method may include analyzing the arrival of concentration peaks of each indicator to determine the percentage of influx that occurs between the locations of the indicators.

The method may include analyzing the rate of decline of the tracer concentration from each tracer location to determine the percentage of formation inflow from each inflow zone.

The method may include changing the flow rate of the production stream in the production string to pause the tracer release device and/or to release a high concentration of tracer molecules from the tracer release device.

The method may include temporarily changing the flow rate of the production stream to a higher or lower flow rate of the production stream to pause the tracer release device and/or release high concentration tracer molecules from the tracer release device.

The method may include detecting the indicator using methods selected from the group consisting of optical detection, optical fibers, spectrophotometric methods, PCR methods combined with sequential analysis, chromatographic methods and/or radioactive analysis. The method may include optical detection of the indicator.

Embodiments of the eighth aspect of the invention may include any of the features of the first through seventh aspects of the invention or embodiments thereof, or vice versa.

In accordance with a ninth aspect of the invention, there is provided a method of releasing a tracer into the production stream of a hydrocarbon production well, comprising:

installing at least one indicator release device connected to the production string in the hydrocarbon production well at the inflow location,

wherein the device for releasing the indicator contains

a volume of fluid, an indicator material located in said volume of fluid, an outlet into said volume of fluid, and a controllable valve configured to selectively control the flow of fluid through said at least one outlet,

creating a transient process in the produced stream for releasing at least one indicator from said at least one device for releasing the indicator into the production string.

The method may include providing a transient for actuating a controllable valve to release at least one tracer from said at least one tracer release device into a production string. The method may include changing the flow rate of the produced stream to create a transient in the produced stream.

Embodiments of the ninth aspect of the invention may include one or more of any of the features of the first through eighth aspects of the invention or embodiments thereof, or vice versa.

In accordance with a tenth aspect of the invention, there is provided a method for collecting samples for analysis in assessing the flow profile of a hydrocarbon production well, the method comprising:

installing at least one indicator release device connected to the production string in the hydrocarbon production well at the inflow location,

wherein the device for releasing the indicator contains:

a volume of fluid, an indicator material located in said volume of fluid, an outlet into said volume of fluid, and a controllable valve configured to selectively control the flow of fluid through said at least one outlet,

creating a transient in the production stream to release at least one tracer from said at least one tracer release device, and

sampling at a location downstream of indicator sources after creating a transient process in the produced stream.

The method may include providing a transient for actuating a controllable valve to release at least one tracer from said at least one tracer release device into a production string.

Embodiments of the tenth aspect of the invention may include one or more of any of the features of the first through ninth aspects of the invention or embodiments thereof, or vice versa.

In accordance with an eleventh aspect of the invention, there is provided a method for detecting at least one indicator in a production stream, comprising:

installing at least one indicator release device connected to the production string in the hydrocarbon production well at the inflow location,

wherein the device for releasing the indicator contains:

a volume of fluid, an indicator material located in said volume of fluid, an outlet into said volume of fluid, and a controllable valve configured to selectively control the flow of fluid through said at least one outlet,

creating a transient in the production stream to release at least one tracer from said at least one tracer release device, and

measuring the concentration of the indicator in the produced stream in real time.

Embodiments of the eleventh aspect of the invention may include one or more of any of the features of the first through tenth aspects of the invention or embodiments thereof, or vice versa.

In accordance with a twelfth aspect of the invention, there is provided a method for estimating the inflow profile of at least one of the downhole fluids into a production well with at least one inflow zone into the production stream, comprising:

placing at least one indicator release device connected to the production string at known levels of the well,

the device for releasing the indicator contains:

a volume of fluid and indicator material located in said volume of fluid, at least one outlet into said volume of fluid, and at least one controllable valve configured to selectively control the flow of fluid through said at least one outlet ,

creating a transient process in the produced stream to release at least one indicator from said at least one indicator release device,

measurement of indicator concentration in the produced stream

and estimating a flow profile for at least one of the well fluids based on the type of tracer and measured tracer concentrations.

Embodiments of the twelfth aspect of the invention may include one or more of any of the features of the first through eleventh aspects of the invention or embodiments thereof, or vice versa.

In accordance with a thirteenth aspect of the invention, there is provided a system for monitoring the influx of fluid into a hydrocarbon production well, comprising:

at least one probe, and

at least one indicator release device for connection to the production string, wherein said at least one indicator release device comprises

at least one outlet,

at least one indicator chamber in fluid communication with said at least one outlet,

indicator material located in the indicator chamber, and

at least one valve configured to selectively control the flow of fluid through said at least one outlet.

Said at least one probe may be placed in the production stream in the production casing. The at least one probe may be located inside the well or on the surface. The at least one probe may be a sampling probe, a sensor probe, and/or a real-time sensor probe.

Embodiments of the thirteenth aspect of the invention may include one or more of any of the features of the first through twelfth aspects of the invention or embodiments thereof, or vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, by way of example only, various embodiments of the invention are described with reference to the drawings, in which:

Fig. 1 is a simplified cross-sectional view of a production well with a tracer release system installed in accordance with one aspect of the invention,

Fig. 2A-2C are enlarged cross-sectional views of an indicator release device of the indicator release system shown in FIG. 1, illustrating the steps of operation of a device for releasing a long-lived tracer suspended in a well with a normally low production flow rate,

Fig. 3A to 3C are enlarged cross-sectional views of an indicator release device of the indicator release system shown in FIG. 1, illustrating the steps of operation of a device for releasing a long-lived tracer suspended in a well with a normally high production flow rate,

Fig. 4A-4C are enlarged cross-sectional views of an indicator release device of the indicator release system shown in FIG. 1, illustrating the operating steps when pausing the device to release an indicator at two valve thresholds,

Fig. 5A to 5D are enlarged cross-sectional views of two indicator release devices of the indicator release system shown in FIG. 1, illustrating the steps of operation of a device for releasing a long-lived tracer suspended in a well with a normally low production flow rate,

Fig. 6A through 6D are enlarged cross-sectional views of two indicator release devices of the indicator release system shown in FIG. 1, illustrating the steps of operation of a device for releasing a long-lived tracer suspended in a well with a normally high production flow rate,

Fig. 7A-7C are enlarged cross-sectional views of a tracer release device with two valve assemblies configured in accordance with one aspect of the invention, illustrating the operation of an inlet valve and an outlet valve for a long-lived tracer release device suspended in a well with a normally low production flow rate.

Fig. 8A-8C are enlarged cross-sectional views of a dual-valve tracer release device made in accordance with one aspect of the invention, illustrating the operation of an inlet valve and an outlet valve for a long-lived tracer release device suspended in a well with a normally high production flow rate.

Fig. 9A-9C are enlarged cross-sectional views of an indicator release device with an inlet in fluid communication with the annulus, in accordance with one aspect of the invention,

Fig. 10A-10C are enlarged cross-sectional views of a tracer release device with a limiting device, illustrating the steps of operation of the tracer release device suspended in a well with a normally low production flow rate.

Fig. 11 is an enlarged cross-sectional view of an indicator release device with an inlet and an outlet in fluid communication with the annulus, in accordance with one aspect of the invention,

Fig. 12A and 12B depict schematic views of components of a kinematic valve assembly for use in an indicator release device made in accordance with one aspect of the invention,

Fig. 13A and 13B are schematic views of components of a kinematic valve assembly for use in an indicator release apparatus configured in accordance with a further aspect of the invention;

Fig. 14A and 14B depict schematic views of components of a kinematic valve assembly for use in an indicator release device made in accordance with one aspect of the invention,

Fig. 15A and 15B are schematic views of components of a differential pressure valve assembly for use in an indicator release apparatus configured in accordance with a further aspect of the invention;

Fig. 16A, 16B and 16C depict schematic views of control mechanism components for use in an indicator release device made in accordance with one aspect of the invention,

Fig. 17A, 17B and 17C depict schematic views of probe components for use in detecting a released indicator, in accordance with one aspect of the invention,

Fig. 18A, 18B and 18C depict alternative cross-sectional views of the components of the probe shown in FIG. 17A,

Fig. 19 is a cross-sectional view of the probe test connector shown in FIG. 17A,

Fig. 20A and 20B are simplified cross-sectional views of a production well illustrating steps for installing a tracer release system, in accordance with one aspect of the invention,

Fig. 21A, 21B, and 21C are enlarged cross-sectional views of a tracer release apparatus with an outward discharge section in fluid communication with a production string, in accordance with one embodiment of the invention, illustrating the steps of operation of a long-lived tracer release apparatus suspended in a normally low flow well. flow, and

Fig. 22A, 22B, and 22C are enlarged cross-sectional views of a tracer release apparatus with an outward discharge section in fluid communication with a production string, in accordance with one embodiment of the invention, illustrating the steps of operation of a long-lived tracer release apparatus suspended in a normally low flow rate well. flow.

DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATION OPTIONS

Fig. 1 is a simplified cross-sectional view of a production well 10. The well contains a central production string 12 surrounded by an annular space 11. Volumes of fluid influx enter the well from the formation into the central production string 12 through individual inflow points. An indicator release device 16 is installed in or on the production string and is located adjacent to each inflow point. Tracers are released and measured at the surface to provide information about where inflows are occurring and at what rates. In this example, there are four inflow points 14a, 14b, 14c and 14d and four indicator release devices 16a, 16b, 16c and 16d, each with an indicator source with a separate indicator material different for each inflow location. However, there may be a different number of inflow zones and/or indicator release devices than that shown in FIG. 1. The controlled throttle unit 15 is designed to control the speed of the produced flow. In FIG. 1, a controllable throttling assembly 15 is connected to the production string to control fluid flow or system pressure downstream of the production string. However, it should be understood that the choke can be located in the well in different places.

Fig. 1 depicts an overview of the monitoring principle with the steps indicated: A) Controlled release of tracers at multiple locations along a well, B) Flow to the top and detection of the tracer, C) Monitoring of the received tracer signal and interpretation of the data to determine zonal inflow along at least one well well fluid.

The arrows in the examples below indicate the direction of fluid movement and indicate the flow rate (for example, two arrows indicate a higher flow rate than one arrow and vice versa).

Fig. 2A-2C are enlarged cross-sectional views of the indicator release device 100. The device is installed on or inside the production string 12. The indicator release device has an inlet 118 and an outlet 120 in fluid communication with the production string 12. The device 100 has an annular chamber 121 surrounding the production string with a flow channel 122 that contains indicator material 124. The indicator material may be located in the flow channel to allow the fluid to contact the tracer material and pass around the tracer material in the channel 122. The tracer material 124 can release tracer molecules or particles when exposed to a target well fluid, such as oil, gas or water.

The valve assembly 126 is secured by a movable closure member 125 to selectively open and close the outlet 120a to control the flow of fluid from the flow path 122 into the production string.

In the examples shown in FIGS. 2A-2C, the valve assembly is a kinematic valve installed on the inner diameter of the production string. The kinematic valve has a movable spool element 125. However, it should be understood that the valve assembly may be installed within the interior of the indicator release device.

Valve assembly 126 is a kinematic valve configured to open and close spool member 125 in response to changes in production flow rate. In this case, the change in the produced flow is controlled by adjusting the throttle assembly 15. The valve assembly is configured to open when the flow rate is above a preset threshold value of the produced flow and to close when the flow rate is below the set threshold value.

At normal low production flow rates, the flow rate is below a preset production flow rate threshold, so valve 126 remains closed.

The indicator material 124 in the flow channel remains open to the fluid volume in the flow channel 122 during the period of time that the valve 126 is closed, creating a high or increased concentration of indicator molecules 124a in the fluid volume of the indicator release device.

When a tracer analysis operation is required to be performed, the throttling assembly is temporarily adjusted to increase the production flow rate to a second flow rate that is higher than a preset threshold value for valve 126, wherein valve 126 opens outlet 120, releasing the tracer molecule fluid at a high or an increased concentration in the form of an indicator cloud into the production string 12. The indicator cloud is carried to the surface by the produced fluid. The tracer cloud produces a high amplitude peak signal at the detection point and the tracer concentration is determined. On the surface, the indicator can be detected by the probe assembly, which is further discussed with reference to FIG. 17A-19.

To pause the indicator release device, the throttling assembly is adjusted to reduce the production flow to a flow rate that is lower than a predetermined threshold value for the valve assembly, the valve assembly being actuated to move the spool member to close the outlet 120, thereby closing thus, the flow channel and allowing the concentration of the indicator to accumulate.

By exposing the indicator to the extracted flow only when the indicator cloud is about to form and be released, the resource of the indicator can be increased. A small volume of fluid in a flow channel can quickly become enriched in indicator molecules. As the small volume of fluid becomes enriched, the rate of release of indicator molecules from the indicator material may be reduced.

This may allow the use of a wide range of indicators, including polymer systems with rapid release of indicators. By installing rapid release indicator polymer systems in the indicator release apparatus, it is possible to avoid significant time delays between indicator assays. This is in contrast to the standard practice of extending tracer life by reducing the rate of tracer release so that it stays in the well as long as possible.

Fig. 3A-3C depict the design of a high flow check valve assembly compared to FIGS. 2A-2C. In FIG. 3A-3B, indicator release device 150 has a valve assembly 176 configured to open outlet 170 below a preset flow rate threshold and close outlet 170 above that threshold.

Under normal high production flow rates, as shown in FIG. 3A, the production flow rate exceeds a preset production flow rate threshold and, therefore, valve 176 remains closed. The indicator material 174 in the flow channel remains open to a volume of fluid, and a high concentration of indicator molecules accumulates in this volume of fluid.

To actuate valve 176 to open outlet 170, the throttling assembly is temporarily adjusted to reduce the production flow to a flow rate that is lower than a predetermined threshold for valve 176, at which time the valve assembly opens, releasing the accumulated elevated concentration of tracer molecules as indicator clouds into the production stream, as shown in FIG. 3B. The tracer clouds move toward the surface in the production flow and create a noticeable high amplitude tracer response peak at the detection point.

When the throttle assembly (not shown) is adjusted to return to normal production flow rate that is above the valve threshold level, valve 176 is activated to close outlet 170, as shown in FIG. 3C.

Fig. 4A-4C show an alternative design of the indicator release device shown in FIG. 2A and can be understood from the above description of FIG. 2A-2C.

However, the indicator release device 200 has a differential pressure valve 226 with two controllable actuation threshold levels for actuating the valve 226 to close the outlet 220. The valve is configured to close the outlet 220 at a flow rate above a first set production flow rate threshold. flow and below the second established threshold value of the flow rate of the produced flow. Therefore, valve 226 is configured to open over a range of production flow rates between two threshold levels.

Under normal high production flow rates, as shown in FIG. 4A, the flow rate is above the first preset threshold flow rate, and therefore the valve 226 is actuated to close the outlet 220. However, adjusting the throttle assembly to reduce the flow rate of the production stream below the specified threshold value operates the valve, opening the outlet hole and allowing the release of the indicator cloud, as shown in Fig. 4B.

Further adjustment of the throttle assembly to reduce the production flow rate below a second preset production flow rate threshold actuates the valve and closes the outlet. This means that in the event of a well shutdown, the valve closes the outlet and limits the volume of fluid with which the tracer material comes into contact, thereby extending the life of the tracer.

Fig. 5A-5D illustrate the operating steps of two indicator release devices, showing the release of the indicator into the production stream. In wells with more than one tracer release device, the valve assemblies for each tracer release device may be configured to simultaneously release the tracer cloud. In FIG. 5A-5D illustrate the operating steps of valve assemblies for synchronized tracer release from two downhole tracer release devices.

Fig. 5A-5D show a tracer release system 250 having two tracer release devices 266a and 266b, each having a valve assembly 276a, 276b, respectively, configured to open an outlet in the tracer release device above a predetermined production flow rate threshold. flow and closure below a preset threshold. Valves 276a and 276b are closed during normal low output and open during temporary high output.

The valve 276a and 276b of the indicator release device 266a and 266b is configured to open above a preset production flow rate threshold and close below the threshold. During normal low performance, flow is below a preset flow threshold and therefore valve assemblies 276a and 276b remain closed, as shown in FIG. 5A. Fluid flows from the production string through inlets 268a and 268b into flow path 472. The tracer material is exposed to the fluid and tracer molecules are released into the fluid.

To release the indicator, the production string choke assembly is adjusted to increase the production flow to a second flow rate that is well above the preset threshold for valve assemblies 276a and 276b. As a result, the valve assemblies 276a and 276b open simultaneously, allowing the indicator clouds to be released simultaneously from the indicator release device 266a, 266b, as shown in FIG. 5V.

To pause the device to release the indicator, the throttle assembly is adjusted to reduce the produced flow to a third flow rate. The third flow rate is higher than the first flow rate and lower than the second flow rate. At the third flow rate, valve assembly 276b is closed, as shown in FIG. 5C. However, since the two different tracer release devices are located at different locations in the well, they are subject to changes in local pressure, and therefore the pressure difference required to close the valve assemblies is not the same. As a result, valve assembly 276b is closed while valve assembly 276a remains open.

The throttle assembly is adjusted to reduce the produced flow back to the first flow rate. Upon first flow, valve assembly 276a returns to the closed state, as shown in FIG. 3D.

Fig. 6A-6D depict an indicator release system 300 that has an alternative valve arrangement to that shown in FIG. 5A-5D, configured to close the outlet openings above a preset threshold value of the flow rate of the produced stream and open below the threshold value. The valves close during normal high flows and open during temporary low flows.

The valve assemblies 326a and 326b of the indicator release device 316a and 316b are configured to open at a flow rate above a preset threshold flow rate of the produced stream and close at a flow rate above the threshold level.

During normal high performance, flow is above a preset threshold and therefore valve assemblies 326a and 326b remain closed, as shown in FIG. 6A.

To release the indicator, the throttling assembly connected to the production string is adjusted to reduce the production flow to a second flow rate that is significantly lower than the preset threshold for valve assemblies 326a and 326b. As a result, the valve assemblies 326a, 326b open simultaneously, allowing the accumulated concentrations of indicator molecules in the indicator release device 316a, 316b to be released simultaneously, as shown in FIG. 6B.

To pause the indicator release device, the throttle assembly is subsequently adjusted to increase the production flow to a third flow rate to close the valve assembly 326b, as shown in FIG. 6C. Due to changes in local pressure, additional adjustment of the throttle back to the first flow rate is required to achieve the pressure difference required to close valve 326a and outlet 320a.

Fig. 7A depicts an indicator release device 350 comprising two valve assemblies 376a and 376b. In this example, the valve assemblies are kinematic valves.

The indicator release device 350 has an inlet 368 and an outlet 370 in fluid communication with the production string 12. The indicator release device has a flow channel 372 that contains indicator material 374. The indicator material may be located in the flow channel to allow fluid pass around the indicator in channel 372. The indicator material 374 is configured to release indicator molecules or particles when exposed to a target fluid, such as oil, gas or water.

The first valve 376a has a movable element for selectively opening and closing the outlet 370 to control the flow of fluid from the flow path 372 into the production string. The second valve 376b is configured to selectively open and close the inlet port 368.

In the example shown in FIG. 7A, the valve assembly is mounted on the outer wall of the flow channel 372. However, it is understood that the valve assembly may be mounted on the inner wall of the indicator release device.

Fig. 7A-7C illustrate operating steps of two valve assemblies in the indicator release device. This has particular application when the fluid has high mobility, such as gas, to prevent cross-flow, or in heterogeneous formations with high pressure differences between zones in the well. The indicator release device shown in FIG. 7A is designed to pause the long-lived indicator release device to allow the indicator cloud to accumulate.

Valve assemblies 376a and 376b are configured to open at a flow rate above a preset threshold flow rate of the produced stream and close at a flow rate below the threshold value. During normal low performance, as shown in FIG. 7A, the flow rate is below a preset production flow rate threshold and valve assemblies 376a and 376b close outlet 370 and inlet 368, respectively. The indicator chamber is sealed and the fluids surrounding the indicator material in the indicator chamber fluid volume become saturated. indicator particles.

The volume of fluid contacting the tracer material in flow channel 372 allows a cloud of tracer to accumulate, as shown in FIG. 7B. The choke assembly is adjusted to temporarily increase flow in the production string above a preset production flow rate threshold, which activates valve assemblies 376a and 376b to open outlet 370 and inlet 368, respectively, allowing tracer cloud to be flushed from the tracer release device.

In FIG. 8A-8C, the indicator release device 400 is configured for use in a normal high production well. The valve assemblies 426a and 426b are configured to open, respectively, the outlet 420 and the inlet 418 at a flow rate below a predetermined threshold flow rate of the production stream, and to close, respectively, the outlet 420 and the inlet 418 at a flow rate above the threshold value.

During normal high performance, flow exceeds the actuating threshold of valves 426a and 426b, and therefore valves 426a and 426b are closed. The indicator chamber is sealed and the fluids surrounding the indicator material within the indicator chamber fluid volume become saturated with indicator particles. The volume of fluid contacting the indicator material in the flow channel 422 allows an indicator cloud to accumulate.

To release the indicator cloud, the throttling assembly is adjusted to temporarily reduce the flow in the production string below a preset production flow rate threshold, which activates the valve assemblies 426a and 426b to open, respectively, the outlet 420 and the inlet 418, so that the indicator cloud can be flushed from the indicator release device.

Fig. 9A depicts an alternative tracer release device design designed for a low flow well where it may be difficult to create a pressure difference between the flow path and the production string.

The flow channel 472 of the indicator release device 450 includes a flow limiting device 478. The flow restriction device is located or attached to the inner wall of the indicator release device so that it extends inward into the flow channel to reduce the flow area of the flow channel. In this example, the flow restriction device is a nozzle. However, it should be understood that other types of limiting devices may be used.

Nozzle 478 is located in flow path 472 between inlet 468 and outlet 470. Nozzle 478 allows a pressure gradient to be created between flow path 472 and the production string. In low-productivity wells, the choke assembly may not be able to increase flow beyond a preset production flow rate threshold. By installing a flow restrictor in the indicator release device, the pressure difference increases, allowing the valve assembly to be activated.

Fig. 10A-10C depict an enlarged cross-section of an alternative indicator release device design for exposing the indicator material to fluid from the production casing and annulus 11. The indicator release device 500 is mounted on the production string 12. The indicator release device has a first inlet 518 in fluid communication with the production string, and a second inlet 529 in fluid communication with the annulus 11. The indicator release device has an outlet 520. The arrows in FIG. 10A-10C indicate the direction of movement of the fluid.

The indicator release device 500 has a channel 522 that contains indicator material 524. The indicator material may be located in the flow channel to allow fluid to contact the indicator material and flow around the indicator material in the channel 522. The indicator material 524 is configured to release molecules or tracer particles when exposed to a target downhole fluid, such as oil, gas or water.

The indicator release device has a differential pressure valve 526 configured to selectively open and close the outlet 520 to control the flow of fluid from the flow path 522 into the production string.

Valve assembly 526 is a differential pressure controlled valve configured to open and close as the pressure difference changes. In this case, the change in pressure difference is controlled by regulating the flow rate of the produced stream. The valve assembly is configured to open at a flow rate above a preset production stream flow threshold and to close at a flow rate below a preset threshold.

During normal performance, as shown in FIG. 10A, the production flow rate is below a preset flow threshold value and therefore the pressure difference controlled valve remains open. Fluid flows from the annulus 11 through the inlet 529 and from the production string 12 through the inlets 518 into the flow path 522. The tracer material is exposed to the fluid and the tracer molecules are released into the fluid. The indicator-enriched fluid passes through the outlet into the production string and is carried by the production fluid to the surface.

The fluid in the flow channel 522 cannot escape and the concentration of indicator molecules increases.

To open the outlet 520, the throttling assembly is adjusted to increase the flow rate of the produced stream above a preset valve threshold. As shown in FIG. 10C, the valve assembly opens, allowing fluid and a high concentration of indicator to pass through outlet 520 into production string 12.

Fig. 11 is an enlarged section through an alternative design of an indicator release device for exposing the indicator material to fluid from the annulus and releasing an indicator cloud into the annulus. The released tracer cloud may enter the production string through an inlet downstream of the tracer release device. An indicator release device 550 is mounted on the production string 12. The indicator release device has an inlet 568 in fluid communication with the annulus 11 and an outlet 570 in fluid communication with the annulus 11. Arrows in FIG. 11 indicate the direction of movement of the fluid.

The indicator release device 550 has a channel 572 that contains indicator material 574. The indicator material may be located in the flow channel to allow fluid to contact and flow around the indicator material in the channel 572. The indicator material 574 is configured to release molecules or indicator particles when exposed to the target well fluid, for example, oil, gas or water.

Valve assembly 576 is configured to open and close the outlet in response to changes in pressure difference in the fluid flow. In the examples shown in FIGS. 11, the valve element is installed on the outer wall of the flow channel. However, it should be understood that the valve assembly may be mounted on the inner wall of the flow channel.

The tracer cloud is released into the annulus, where it can enter the production string at an inflow point further downstream and travel to the surface.

The valve assemblies described above are configured to open or close when the valve is subjected to a pressure difference that reaches a predetermined level. For example, when the pressure difference created by a change in the produced flow causes the movable spool element to move to the closed position.

In the examples discussed above and shown in FIGS. 1A-11, the indicator material is any luminescent indicator, for example, a dye with a narrow absorption band or quantum dots. Examples of a suitable luminescent dye are sulfo-rhodamine B, the absorbing dye is 2-[2-[2-chloro-3-[2-(1,3-dihydro-1,3-trimethyl-2H-indol-2-ylidene)ethylidene ]-1-cyclohexen-1-yl]ethenyl]-1,3,3-trimethyl-3H-indolium chloride, quantum dots can be CdSe quantum dots of several nanometers in size. The dye protection particles can be made of porous silica gel or any other material, and the particles can also have a core-shell structure.

However, it should be understood that other types of indicators may be used, including chemical, fluorescent, phosphorescent, magnetic, DNA and radioactive compounds, which can be used with appropriate detection equipment.

Fig. 12A-16B depict illustrative valve assemblies of various types that may be used in the indicator release assemblies described above with reference to FIGS. 1A-11. The kinematic valve assembly shown in FIG. 12A-14B, or the differential pressure valve assemblies shown in FIG. 15A-16B may be used to throttle or prevent flow into and/or out of the indicator release device.

Fig. 12A depicts an indicator release device 600 with a kinematic valve assembly 626. The kinematic valve is located in the inner diameter of the production string. The kinematic valve has a spool drive element 610, which in FIG. 12A is shown pressed into the closed position by spring 612. Valve spool actuator 610 is linearly movable between a closed valve position and an open position shown, respectively, in FIG. 12A and 12B.

In the first valve device shown in FIG. 12A, spring 612 is a compression spring pressed into the fully closed position at low production flow. In response to the high flow rate of the produced stream, the flow acting on the spool element 610 is sufficient to compress the spring 612, which moves the spool element 610 to the fully open position. Under low production flow conditions, the force exerted on the spool member 610 by the produced flow is insufficient to overcome the force of the spring 612. The spring expands and moves the spool member to the fully closed position, as shown in FIG. 12V.

Fig. 13A depicts an indicator release device 650 with a speed valve assembly 676. Spring 662 is an extension spring pressed to the open position. In response to high production flow rates, such as during normal production, the flow acting on spool element 660 is sufficient to overcome the force of spring 662. The spring expands, moving spool element 660 to the closed position. Under conditions of low production flow, the force exerted on the spool element 662 by the production flow is insufficient to overcome the spring force. The spring compresses and moves the spool element to the open position, as shown in FIG. 13V.

Although in Fig. 12A, 12B, 13A and 13B show a spool element movable between a fully open and fully closed position, it should be understood that the spool element may be located in positions intermediate between a fully open position and a fully closed position. The spool element can be set to partially open and partially close depending on the production flow rate to throttle or restrict flow through the valve.

Fig. 14A and 14B depict an enlarged view of the kinematic valve assembly 726 in the indicator release device 700. The remaining components of the device have been removed in these drawings for the sake of clarity. The valve assembly has a valve body 710 with a port 712 extending through a wall of the valve body and aligned with an indicator outlet 720. The spool element 714 is supported by the valve body and has seals 713 and 715 at each end thereof. The spool element can move axially relative to the valve body. Spool member 714 has a port 717. The spool member is movable from a closed position in which the spool member port 717 is not aligned with port 712 and outlet 720, as shown in FIG. 14A to an open position in which spool port 717 is aligned with port 712 and outlet 720, as shown in FIG. 14V.

The spool element bias mechanism, in this case spring 719, is located between a lug 721 on the valve body and a lug 723 on the spool element.

In this example, the spool element bias mechanism is a spring 721, however, it should be understood that other bias mechanisms, such as a pressure chamber containing a gas such as nitrogen, can be used.

The spool element 714 acts as a piston, which can be moved axially by the production flow, acting on the spool element 714 through the spool element protrusion 725. When the fluid flow acting on the protrusion 725 reaches a predetermined amount, a pressure force compresses the spring 714 to move the spool element axially so that the spool element port 717 is aligned with the port 712 and the outlet 720.

The spool element will remain in the open position as shown in FIG. 14B until the force from the produced stream is sufficient to keep the spring 714 compressed.

Once the production flow rate decreases below a predetermined value, the spring force can overcome the pressure force acting on the spool element protrusion 725. The spool element moves to a closed position in which the spool element port 717 is not aligned with the port 712 and outlet 720.

The force acting on the spool element can be adjusted to decrease or increase the flow rate in the production string by controlling a throttle connected to the production string. In this example, the spring is a compression spring. However, it will be understood that an extension spring can be used.

Fig. 15A and 15B depict an enlarged view of the differential pressure controlled valve assembly 826 in the indicator release device 800. Valve assembly 826 is located within the indicator release device so that it is not constrained by the internal diameter of the production string. Other device components in these drawings have been removed for clarity.

Valve assembly 826 has a valve body 810 with an outlet port 812 extending through a wall of the valve body and aligned with an indicator outlet 820. The spool element 814 is movable axially relative to the valve body. Valve body 810 has an inlet port 817 in fluid communication with valve seat 819. In the closed valve position, the spool element is located in the valve seat 809, and the spool element closes the outlet port 812 and the outlet 820, as shown in FIG. 15A. In the open position of the valve, the spool element moves axially from the valve seat, and the outlet port 812 and outlet 820 are in fluid communication with the internal volume within the indicator release device, as shown in FIG. 15V.

The spool element bias mechanism, in this case spring 819, is located between a lug 821 on the valve body and a lug 823 on the spool element.

In this example, the spool element bias mechanism is a spring 821, however, it should be understood that other bias mechanisms may be used, such as a pressure chamber containing a gas such as nitrogen.

The spool element 814 acts as a piston that can move axially due to a pressure difference between the indicator release device and the production string. Pressure from the indicator release device is applied to the spool member 814 through the inlet port 817. Pressure from the production string is applied to the spool member 814 through the outlet port 812 and the outlet port 820. When the pressure applied to the inlet port 817 reaches a predetermined value, the pressure force compresses the spring 814 to move the spool element axially away from the valve seat 809 so that the spool element opens the outlet port 812 and the outlet 820.

The spool element will remain in the open position as shown in FIG. 15B until the pressure difference between the indicator release device and the production string is sufficient to keep spring 814 compressed.

Once the pressure difference between the indicator release device and the production string decreases below a predetermined value, the spring force can overcome the pressure force acting on the spool element. The spool element moves to a closed position, in which the spool element is located in the valve seat 809.

Although in the above examples described with reference to FIGS. 12A-15B, the valves are described as normally closed, it is understood that the valves can be configured to be normally open and move to a closed position in response to a change in flow rate and/or a change in pressure difference.

The pressure acting on the spool element can be adjusted by decreasing or increasing the pressure in the production string by controlling a throttle connected to the production string. In this example, the spring is a compression spring. However, it will be understood that an extension spring can be used.

Fig. 16A depicts a valve control mechanism 850 for controlling actuation of the valve. In this example, the valve is a spool valve.

The control mechanism 850 has a spool member 864 with a keyway 880, as best shown in FIG. 16V. The keyway 880 includes a plurality of axial grooves or tracks 882 formed around the outer surface of the spool element. A fixed locating pin 884 mounted on the valve body 860 is located between the spool element and the valve body and is movable within the keyway. The spool member has a port 867 that is configured to align with the outlet of the device to release the indicator when it is in the open valve position. The spool element port 867 is configured to close in the closed position of the valve.

Axial movement of the spool element 864 in response to a change in fluid velocity, as described with reference to FIG. 12A, 12B, 13A and 13B, or in response to a change in pressure difference, as described with reference to FIG. 14A and 14B causes the locating pin 884 to move into the keyway 880.

Depending on the design of the keyway 880, the spool element 864 is prevented from moving to the open position until a selected number of pressure or fluid velocity cycles are applied to the spool element. Alternatively, the spool element 864 is prevented from moving to the closed position until a selected number of pressure or fluid velocity cycles are applied to the spool element.

When the locating pin 884 passes through the keyway 880, the spool element 864 moves to actuate the valve between a closed or open position. Guides 882 in the keyway are of varying lengths and are used to control valve actuation.

In the example shown in FIG. 16B and 16C, the keyway 880 has alternating long guides 890 and short guides 892 located around the periphery of the spool element. When the locating pin is located inside the long guide 890, the valve is in the open position and the spool port is aligned with the indicator outlet port. Movement of the spool element in response to flow rate or pressure difference moves the spool element into a short path. When the pin is in the short track 892, the spool element moves to a position in which the spool element port is not aligned with the outlet of the indicator release device. Further movement of the spool element in response to flow rate or pressure difference moves the spool element, but if the locating pin is still in the short track, the valve remains in the closed position.

Another embodiment of the valve control mechanism 850 is that the spool member may have ports 865a, 865b of different sizes, as best illustrated in FIG. 16A. Each port size may correspond to a different axial track 882 in the keyway 880. For example, when the locating pin 884 is in the first track, the spool member ports 865a, 865b may be blocked and the valve will be closed. When the locating pin 884 is in the second track, the spool element is moved to align the small spool element port or series of small spool element ports 865a with the indicator release port, thereby gradually releasing the indicator from the device through the small spool element port. However, when the locating pin 884 is located on the third track, the spool element moves to align the larger spool element port or set of large ports 865b with the outlet of the indicator release device, thereby quickly releasing the indicator from the device through the large spool element port.

Another feature of the valve control mechanism may be configured such that the spool member port may be positioned at positions intermediate between fully open and fully closed positions corresponding to different axial paths in the keyway. This allows controlled opening, closing, partial opening or partial closing of the valve.

While the above examples describe a control mechanism used to control actuation of a valve to open and close an outlet on an indicator release device, it is understood that the control mechanism may be used to alternatively or additionally control actuation of a valve to open and close an inlet port devices for releasing the indicator.

Fig. 17A is a schematic view of a probe 900 used to detect a tracer in a production stream. The probe 900 is installed in the production string 12. As shown in FIG. 17A, the stream consists of three stream components: oil (Fo), gas (Fg) and water (Fw).

The probe 900 has a number of sensors 912 located on the probe body 910, located at different depths, to detect the tracer at different phase layers in the segregated flow. Communication line 914 connects sensors 912 to analysis equipment 915 via measurement connector 920. Communication line 914 may be a fiber optic cable for driving and detecting indicators. The flange 918 or similar connection/access port may be a sand detection port located in the pipe wall.

Fig. 17B illustrates the position of the protective cover 925 located over the fiber optic connector 927 of the probe 900 during installation on the column 12 and removal of the cover in FIG. 17C during operation. In FIG. 17C shows that when the cover 925 is removed, the fiber bundle 928 connected to the analytical equipment 915 is attached to the fiber connector 927. The probe 900 can be inserted into the production string 12 using standard off-the-shelf equipment such as a Roxar hydraulic extraction tool, or using existing access points to the production string 12, such as a ball valve, gate valve, or special instrumentation flange, preferably during operation. There are known insertion and extraction methods based on hydraulic and mechanical principles, such as those offered by Roxar and Mirmorax.

Fig. 18A is a simplified cross-sectional side view of probe 900. The probe has a hollow body 911 and a sealing thread 913 for mounting the probe. The probe has several 912 sensors located on a hollow body. The sensors have viewing windows 930, which can be made of chemically and mechanically resistant glass. Behind the windows 930 are bundles of light transmitting fibers or individual fibers 932a connected to a driver to excite an indicator in the production stream. Also located behind the windows 930 are bundles of light receiving fibers or single fibers 932b coupled to signal receiving equipment.

Transmission fiber bundles 932a are connected to an excitation source and are used to transmit light into a fluid. Receive fibers 932b are configured to transmit received signals to analytical equipment.

Fig. 18B depicts a cross-section of a possible arrangement of optical fibers behind the viewing window 930, with light transmitter fibers 932a surrounding light receiving fibers that are connected to the signal receiving equipment.

Fig. 18C is a simplified illustration showing an enlarged cross-section of sensor 912. The probe has a transparent window, either parallel to the surface or in the form of a lens, for focusing light emitted by an external phase (fluid) located facing the possible flow (not shown).

Illustrated is a fiber optic cable 932a for transmitting ambient fluid light (emitted wavelength) from the probe to an external detection unit outside the pipe. If the transparent window is a lens, then the end of the fiber must be at or close to the focal point of the lens to collect as much of the emitted light as possible. The probe main body 911 is illustrated in FIG. 18C with 933 channels designed to support fiber optic cables and cavities to hold lenses. Fiber optic cables 932 run through the housing for other sensor locations. A fastening threaded connection is shown around the lens/window to hold the window in place, preferably with a 936 O-ring or similar fitting on each side of the window for insulation.

In the examples discussed above with reference to FIGS. 1A-11, the indicator material and the released indicator molecules are either narrow band luminescent dye or quantum dots. Examples of a suitable luminescent dye are sulfo-rhodamine B, the absorbing dye is 2-[2-[2-chloro-3-[2-(1,3-dihydro-1,3-trimethyl-2H-indol-2-ylidene)ethylidene ]-1-cyclohexen-1-yl]ethenyl]-1,3,3-trimethyl-3H-indolium chloride, quantum dots can be CdSe quantum dots of several nanometers in size. The dye protection particles can be made of porous silica gel or any other material, and the particles can also have a core-shell structure.

The spectral window in which indicators can be detected by probe 900 ranges from 500 nm to 2300 nm. The spectral window is wider for oily fluids with low asphaltene and resin content, such as light oily fluids and condensates, and smaller for heavy oily fluids, from 1000 to 2300 nm. Even in this wavelength range, a typical oil-containing fluid transmits only 10 to 30% of light through a 2 mm thick film and only 1 to 9% through a 4 mm thick film. However, the use of backscattering luminescence allows one to overcome this difficulty. In this case, the sensors are suitable for detecting luminescent radiation.

A method for detecting released indicator from an indicator release device involves emitting light from a light source into a production stream through transmission fibers 932a in each sensor 912. The light generates an indicator-specific glow in indicators present in the stream. Backscattered light is collected and received through receiving fibers 932b in each sensor 912.

The received signal is processed to calculate received light intensities representative of the indicators and record light intensities in the appropriate wavelength range. The advantage of irradiating light into sensors arranged in an array across the flow or along a sufficient portion of the cross-section is that all phases present can be covered. The light intensity is sufficient to detect the luminescence peaks of the indicators.

The characteristics of each indicator can be calculated and controlled, including concentration and arrival time, based on light intensity values. Such a characteristic feature may be a signal peak, as indicated above.

The method may include calculating the difference in arrival time between indicator responses from each device location to issue an indicator for all monitored phases. Spatial differences between known tracer release device locations and estimated arrival times allow inflow profiles into the wellbore to be estimated and monitored.

Fig. 19 is a cross-sectional view of a test connector 920. The connected test connector is located above the transmit fibers 932a and receive fibers 932b. Illustrated is the optical input through a connector that provides a seal between the fibers and the main body of the probe. After installing the 900 probe, external devices (light source and sensor) are connected using standard connections. Optical feed-through connections can be found for both single fibers and fiber bundles. For example, supplied by SQS Vlaknova Optika AS. Other specified features are a set screw that holds the probe in place, a flange permanently attached to the pipe, and an O-ring or other seal between the probe and the flange.

In the above examples shown in FIGS. 17-19, detection, monitoring and concentration of the indicator are performed online in real time. However, it should be understood that, alternatively and/or additionally, samples may be collected offline for subsequent analysis.

Detection and/or analysis of the tracer in the production fluid may be a separate method from the release of the tracer from the tracer release device and/or from the sampling. Samples may be collected and the indicator detected at a time or location that is independent of the location of the well and therefore the sampling.

In the above examples, the valve is a spool valve. However, it should be understood that other types of valves may be used.

Fig. 20A depicts a simplified cross-section of a portion of a production well 1000. The well has a central production string 1012 surrounded by an annular space 1011. A landing nipple 1020 is placed in the production string during completion of the wellbore. In FIG. 20A shows a setup for retrofitting device 1050 to release a tracer into a well without having to remove the production string from the wellbore.

As shown in FIG. 20A, the indicator release device 1050 is transported through the production string from the surface using a wireline 1015. It should be understood that other transportation methods can be used, including wireline and coiled tubing. The indicator release device 1050 is sized to engage and connect to the landing nipple 1020 to receive the indicator release device 1050, as shown in FIG. 20V.

The indicator release device 1050 can be installed and/or replaced without the need to bring the production string to the surface. For example, the indicator release device may be removed and/or replaced due to component failure or requirements to change or replace the indicator material or operating parameters of the indicator release device. Additionally or alternatively, the indicator release device 1050 component can be removed, replaced, or adjusted without having to remove the indicator release device 1050 to a surface. For example, a valve on an indicator release device may be removed, replaced, or adjusted due to valve failure or requirements to change valve type or valve operating parameters.

It should be understood that, depending on the operation and configuration of the indicator release device 1050, the landing nipple may have ports in its side wall. The ports may be in communication with the production string and/or the annulus, and when the indicator release device is mounted on the nipple, the indicator release device 1050 may be in fluid communication with the production string and/or the annulus through ports in the nipple.

Fig. 21A-21C are enlarged cross-sectional views of the indicator release device 1100. The indicator release device is mounted on the production string 12. The indicator release device 1116 has an outward outlet portion 1116a with an inlet 1118a in fluid communication with the production string and an outlet 1120a in fluid communication with the annulus 11. The outward outlet portion 1116a has an annular a chamber 1121a surrounding the production string with a fluid volume 1122a between the inlet 1118a and the outlet 1120a. The indicator release device 1100 has an inward outlet portion 1116b with an inlet 1118b in fluid communication with the annulus 11 and an outlet 1120b in fluid communication with the production string 12. The arrows in FIG. 21A-21C indicate the direction of movement of the fluid. The outlet internal section 1116b has an annular indicator chamber 1121b surrounding a production string with a fluid volume 1122b that contains indicator material 1124. The indicator material may be located in the indicator chamber to allow fluid to contact and pass around the indicator material in the volume 1122b fluid medium. The indicator material 1124 is configured to release indicator molecules or particles when exposed to a target downhole fluid, ie, oil, gas or water.

The valve assembly 1126 is secured by a movable closure member to selectively open and close the outlet 1120b to control the flow of fluid from the display chamber 1121b into the production string.

In this example, valve assembly 1126 is a differential pressure valve configured to open and close in response to changes in the pressure difference between the production string and the indicator release device. In this case, the change in pressure difference is controlled by regulating the flow rate of the produced stream. The valve assembly is configured to open when the flow rate is above a preset threshold value of the production flow rate and close when the flow rate is below the set threshold value.

During normal performance, as shown in FIG. 21A, the production flow rate is below a preset flow threshold value and therefore the valve assembly remains closed. Fluid flows from the production string through the inlet 1118a into the fluid volume 1122a of the annular chamber 1121a and through the outlet 1120a of the outflow section 1116a into the annulus 11. The fluid enters the fluid volume 1122b of the inward section 1116b from the annulus 11 through the inlet hole 1118b.

In fluid volume 1122b, the indicator material is exposed to the target fluid, whereby tracer particles are released into the fluid. The indicator material 1124 in the fluid volume remains exposed to the fluid volume in the fluid volume 1122 during the period of time that the valve 1126 is closed, creating a high concentration of tracer particles in the internal fluid volume of the indicator release device.

When a tracer release operation is required, the throttling assembly is temporarily adjusted to increase the flow rate of the production stream to a second flow rate that is higher than a preset threshold for valve 1126, valve 1126 opens outlet 1120b, releasing the fluid and accumulated tracer cloud of high concentration into production string 12. The flow of fluid through the deflected path of the inlet 1118a, the outlet 1120a of the outflow section, and through the inlet 1118b gradually washes a high concentration of indicator molecules from the fluid volume of the indicator chamber into the production string 12 in the form of an indicator cloud. The indicator cloud produces a high amplitude peak signal at the detection point, followed by an indicator signal decay curve that represents the gradual displacement and washout of the indicator from the indicator release device.

Fig. 22A-22C are enlarged cross-sectional views of the indicator release device 1200. An indicator release device is mounted on the production string 12. The indicator release device 1216 has an outflow section 1216a with inlet ports 1218a and outlet holes 1220a in fluid communication with the annulus 11. The outflow section 1216a has an annular indicator chamber 1221a surrounding the production string. with a fluid volume 1222a that contains indicator material 1224. The indicator material is located in the indicator chamber to allow the fluid to contact and flow around the indicator material in the fluid volume 1222a. The indicator material 1224 is configured to release indicator molecules when exposed to a target downhole fluid, ie, oil, gas or water.

The indicator release device 1200 has an inward outlet section 1216b with inlets 1218b in fluid communication with the annulus 11 and outlets 1220b in fluid communication with the production string 12. Arrows in FIG. 22A-22C indicate the direction of movement of the fluid. The inward discharge section 1216b has an annular chamber 1221b surrounding the production string, with a fluid volume 1222b between the inlet 1218b and the outlet 1220b.

The valve assembly 1226 is secured with a movable closure member to selectively open and close the outlets 1220b to control the flow of fluid from the annular chamber 1221b into the production string.

In this example, valve assembly 1226 is a pressure differential valve configured to open and close in response to changes in the pressure difference between the production string and the indicator release device. In this case, the change in pressure difference is controlled by regulating the flow rate of the produced stream. The valve assembly is configured to open at a flow rate above a preset production stream flow threshold and close at a flow rate below a preset threshold.

During normal performance, as shown in FIG. 22A, the production flow rate is below a preset flow threshold and therefore the valve assembly remains closed. Fluid flows from the annulus through the inlet 1218a into the fluid volume 1222a of the annulus indicator chamber 1221a and through the outlet 1220a of the outflow section 1216a into the annulus 11.

In fluid volume 1222a, the indicator material is exposed to the target fluid, and the indicator molecules are released into the fluid.

The fluid enters the fluid volume 1222b of the inward discharge section 1216b from the annulus 11 through the inlet 1218b. Fluid containing indicator molecules cannot enter the production string while valve 1226 is closed.

When a tracer release operation is required, the throttling assembly is temporarily adjusted to increase the production flow rate to a second flow rate that is higher than a preset threshold for valve 1226, valve 1226 opens outlet 1220b, releasing fluid and tracer molecules into the production string. 12. The indicator-rich fluid is gradually washed out from the fluid volume 1222b into the production string.

The released indicator produces a high amplitude peak signal at the detection point, followed by a decay curve of the indicator signal that indicates gradual displacement and washout of the indicator from the indicator release device.

In the above example, the indicator material is located in the annular chamber 1221a of the outflow section 1216a. However, it should be understood that the indicator material may alternatively or additionally be located in the annular chamber 1221a in the inward venting section 1216. In examples in which the indicator material is located in the outward venting section 1216a and the inward venting sections, the indicator material in the inward venting section 1216a section may be the same as or different from the indicator material in the outward section.

In the above examples described with reference to FIGS. 21A-22C, the tracer release device is configured to pause during normal low production and release a high concentration of tracer by temporarily increasing the flow rate of the produced stream. However, it should be understood that the tracer release device may alternatively be configured to pause during normal high production in high-productivity wells and release the tracer by temporarily reducing the flow rate of the produced stream.

It should also be understood that the indicator release device may be configured to release the indicator during normal production flow and temporarily suspend it by adjusting the flow rate of the production stream.

Moreover, it will be understood that although in the above examples described with reference to FIGS. 21A-22C, there is a valve located at the outlet 1220b of the indicator release device, from the above examples it will be clear that valves may be located at any and/or all of the inlets and/or outlets of the indicator release device. For example, valve assemblies may control the flow of fluid through outlets 1220a and/or 1220b. Alternatively or additionally, valve assemblies may control fluid flow through inlet ports 1218a and/or 1218b. Additionally or alternatively, one or more valve assemblies may be actuated in response to changes in annulus flow.

Data collected at the detection point, as described in the examples above, can be analyzed to identify the arrival of concentration peaks of each tracer to determine the percentage of influx that occurs between tracer locations. The locations of the indicators in the well geometry can be known.

When tracer is released from two or more tracer release devices to the surface, their arrival at the surface is monitored and analyzed to determine the distribution of the influx. The volume between reaching each indicator peak can be proportional to the influx that occurs upstream of each indicator.

The transient processes of the indicator are caused by the velocity field in the well. The arrival of tracers up can be used to estimate the velocity field in the wellbore. Using the velocity field, the inflow profile can be calculated. The concentration of tracers on the surface as a function of time is related to the influx into the well by the velocity field. The concentration of the indicator is determined by the velocity field. The velocity field can be influenced by the geometry of the well and the path of fluid flow.

The model can be used based on the geometry of the production well, which assumes a specific inflow distribution scenario, simulates the arrival times of the tracer peaks, and compares the modeled results with the actual arrival times of the peaks. After several iterations, the model can arrive at a solution that provides an inflow distribution that best matches the actual data. The model may include a simulated transport path corresponding to the actual well transport path downstream of the inflow zones.

The model must include an inflow model that matches the actual influx locations, a tracer system model that even has a model leakage or release rate that matches the actual tracer sources, and a model well transport path that matches the actual producing well.

The concentration of the indicator can be calculated as a function of time. Measured tracer concentrations can be compared with modeled tracer concentrations to provide information about well flow profiles.

Samples can be collected and/or measured downstream at a known sampling time. The influx volume can be calculated based on measured tracer concentrations, their sampling sequence, and well geometry. Inflow volumes can be calculated from transient flow models.

The selection, detection, analysis and/or interpretation of tracer data in a production fluid may be considered separate techniques performed at different times or locations. Detection, analysis and/or interpretation of an indicator in a production fluid may be separate methods for releasing an indicator cloud from the indicator release and/or sampling device.

In real-time detection, the detection, analysis and/or interpretation of tracer data in the production fluid may be considered separate from each other and performed at different times or locations. Detection, analysis and/or interpretation of an indicator in a production fluid may be separate methods for releasing an indicator cloud from the indicator release and/or sampling device.

Model concentrations for each tracer material can be calculated along the simulated downstream flow path of the well as a function of time during the simulated transient occurring in the model.

Additionally or alternatively, data collected at the detection point, as described in the above examples, can be analyzed to determine the rate of decline of the tracer concentration from each tracer location to determine the percentage of formation inflow from each inflow zone.

As indicator is washed out of the indicator release device, zones with high influent flow rates wash out the indicator faster than zones with low influent flow rates, thereby maintaining a high concentration of indicator molecules and creating a profile with steep decay rates. Conversely, the concentration of tracer molecules in the fluid that washes out of the low-productivity zone becomes more dilute as it enters the main stream and moves to the surface. Consequently, the indicator concentration profile has a less steep rate of decline compared to the high-productivity zone. The data can be analyzed to compare the rate of decline of tracer concentrations between each monitored area and quantify the corresponding relative influent flow rates.

Although the above examples describe control and actuation of at least one valve due to pressure differences or changes in flow rate, additionally or alternatively, the at least one valve may be controlled and actuated electrically. Said at least one electric valve can be controlled remotely via wired and/or wireless communication.

The invention provides a method for monitoring the influx of fluid into a hydrocarbon production well, comprising installing at least one device for releasing a tracer into said well at the location of the influx. Said at least one indicator release device comprises:

a volume of fluid and an indicator material located in said volume of fluid. The method includes pausing the tracer release device during production to increase the concentration of tracer molecules in a specified volume of fluid, releasing the tracer molecules from the tracer release device into the produced stream, and detecting the presence of the tracer downstream of the inflow location.

The invention provides a method for monitoring the influx of fluid into a hydrocarbon production well. The method includes installing at least one indicator release device connected to a production string in said well at an inflow location. The indicator release device comprises a volume of fluid, an indicator material located in said volume of fluid, an outlet for said volume of fluid, and a controllable valve configured to selectively control the flow of fluid through said at least one outlet. The tracer release device has a first state in which the control valve is closed to substantially or completely prevent the passage of fluid and tracer material from the specified volume of fluid into the produced fluid through the outlet, and a second state in which the control valve is open to allow allowing fluid and indicator materials to pass from said volume of fluid into the production string through the outlet. The method includes producing hydrocarbons from a well using a device for releasing the indicator in its first state at the first flow rate of the produced flow in the production casing. The method also includes changing the flow rate of the production stream in the production string to a second flow rate of the production stream to operate a controllable valve to cause fluid and tracer material from said volume of fluid to flow into the production string, creating an increased concentration of tracer material in the production string, and detecting the presence of tracer material downstream of the inflow site.

The indicator release system may be capable of selectively shutting off each indicator release device located in or adjacent to the influent zone to accumulate and increase the amount of indicator molecules in the fluid in the indicator release device. The tracer release system may be capable of selectively releasing an increased concentration of tracer molecules in the form of an tracer cloud from the tracer release device into the production stream to create a detectable tracer release at the point of detection. This may provide the ability to calculate and control measurement profiles of flow parameters and inflow into the wellbore.

The advantage of a tracer release system is that it is capable of selectively generating high concentrations of tracer molecules and releasing tracer molecules from the release system without the need to shut in the well.

Another advantage of the tracer release system is that it is capable of releasing an elevated or high concentration of tracer in the form of a tracer cloud that can be detected in the production stream at the surface. It also controls the effect of the produced fluid on the tracer material in the tracer release device, thereby extending the life of the tracer in the well.

Throughout the specification, unless the context clearly indicates otherwise, the terms “comprise” or “include” or variations such as “comprises” or “comprising”, “includes” or “comprising” are to be understood to imply the inclusion of the whole element or group of elements, but not to the exclusion of any other entire element or group of elements. In addition, relative terms such as “downstream”, “upstream”, etc. are used herein to indicate directions and locations as they apply to the accompanying drawings, and should not be construed as limiting the invention and its functionality to particular devices or orientations. Likewise, the term "outlet" should be interpreted to mean an opening that, depending on the direction of flow of the fluid, may also serve as an "inlet" and vice versa.

The foregoing description of the invention is presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments are selected and described to better explain the principles of the invention and its practical application, thereby enabling others skilled in the art to best use the invention in various embodiments and with various modifications as are suitable for the particular intended use. Accordingly, additional modifications or improvements may be included without departing from the scope of the invention as defined by the appended claims.

Various modifications to the embodiments described above may be made within the scope of the invention, and the invention extends to combinations of features other than those expressly claimed herein.

Claims (52)

1. A method for monitoring fluid inflow to a producing hydrocarbon well, including: placing at least one tracer release device in a hydrocarbon production well at an inflow point, wherein said at least one tracer release device comprises a volume of fluid and tracer material located in said volume of fluid, suspending said at least one indicator release device during production to increase the concentration of indicator molecules in said volume of fluid, releasing indicator molecules from said at least one indicator release device into the production stream, and detecting the presence of an indicator downstream of the inflow location. 2. The method according to claim 1, in which samples of the produced stream are taken to detect the presence of an indicator, and sampling is carried out at one or more sampling points. 3. The method according to claim 1, in which the presence of an indicator in the produced stream is detected in real time. 4. A method as claimed in any one of the preceding claims, comprising detecting the presence of an indicator downstream of said at least one indicator release device or on a surface. 5. A method as claimed in any one of the preceding claims, wherein optical monitoring is carried out to detect indicators in the produced stream. 6. The method of any one of the preceding claims, comprising analyzing the arrival of peak concentrations of each indicator to determine the percentage of influx that occurs between the locations of the indicators. 7. The method of any one of the preceding claims, wherein the rate of decline of the tracer concentration from each tracer location is analyzed to determine the percentage of formation inflow from each inflow zone. 8. The method as claimed in any one of the preceding claims, wherein said at least one indicator release device comprises a controllable valve, wherein the method varies the flow rate of the production stream in the production string to actuate the controllable valve to suspend the at least one indicator release device. releasing an indicator and/or releasing a high concentration of indicator molecules from said at least one indicator releasing device. 9. The method of any one of the preceding claims, wherein the flow rate of the production stream is temporarily varied to suspend said at least one tracer release device and/or release a high concentration of tracer molecules from said at least one tracer release device. 10. A method as claimed in any one of the preceding claims, wherein the indicator is detected using methods selected from the group consisting of optical detection, optical fibers, spectrophotometric methods, PCR methods combined with sequential analysis, chromatographic methods and/or radioactive analysis. 11. The method of any one of the preceding claims, wherein two or more tracer release devices are used connected to a production string in a hydrocarbon production well, each tracer release device being located at a different location in the inflow. 12. A system for monitoring the influx of fluid into a producing oil well, comprising at least one probe, at least one indicator release device, configured to be connected to a production string, wherein said at least one indicator release device contains at least one outlet, at least one indicator chamber in fluid communication with said at least one outlet, indicator material located in the indicator chamber, and at least one valve configured to selectively control the flow of fluid through said at least one outlet, wherein said at least one valve is configured to suspend the indicator release device during production to increase the concentration of indicator molecules in the volume of fluid in the indicator chamber. 13. The system of claim 12, wherein the valve is configured to suspend the indicator release device for a period of time sufficient to create a high concentration of indicator molecules that can be detected as a high amplitude indicator response signal at the downstream detection location when the particles or indicator molecules are released from the indicator release device. 14. The system of claim 12 or 13, wherein said at least one indicator release device comprises at least one inlet in fluid communication with said at least one indicator chamber. 15. The system according to any one of paragraphs. 12-14, wherein said at least one valve is configured to open and close in positions intermediate between a fully open position and a fully closed position to selectively control the flow of fluid through said at least one outlet. 16. The system according to any one of paragraphs. 12-15, wherein the indicator material is configured to release indicator molecules from the indicator material into a fluid in the indicator chamber upon contact with a target well fluid. 17. The system according to any one of paragraphs. 12-16, in which the indicator material contains a luminescent dye. 18. The system according to any one of paragraphs. 12-17, wherein said at least one valve is an electrically actuated valve, a differential pressure valve, or a kinematic valve. 19. The system according to any one of paragraphs. 12-18, containing at least one flow limiting device. 20. The system according to any one of paragraphs. 12-19, wherein said at least one tracer release device is modifiable for installation in an existing string, or a component of said at least one tracer release device is configured to be adjustable by cable, wireline, coiled tubing or drill pipe . 21. A method of estimating the inflow profile for at least one of the well fluids in a production well with two or more zones of inflow to the produced stream, comprising placing two or more tracer release devices connected to the production string at known levels of the well, each tracer release device comprising: at least one outlet, at least one indicator chamber in fluid communication with said at least one outlet, separate indicator material located in said at least one indicator chamber, at least one valve configured to selectively control the flow of fluid through said at least one outlet, suspending the indicator release device during production to increase the concentration of indicator molecules in the fluid volume, opening said at least one valve in each indicator release device to release indicator molecules from the indicator chamber into the production stream through said at least one outlet, and measuring an indicator concentration and estimating a flow profile for at least one of the well fluids based on the type of indicator and the measured indicator concentrations. 22. The method of claim 21, wherein the characteristics of the indicator release, sampling time and/or the cumulative volume of influent volumes produced from different influent zones are analyzed. 23. The method of claim 21, wherein said at least one valve is closed for a specified period of time to suspend the indicator release device. 24. The method of claim 21, wherein said at least one valve on each of the two or more devices is opened to release the indicator at the same time. 25. Method of sampling for analysis when assessing the inflow profile of a producing hydrocarbon well containing: at least one tracer release device connected to a production string in a hydrocarbon production well at an inflow point, wherein said at least one tracer release device comprises a volume of fluid, tracer material disposed in said volume of fluid, an outlet opening into said volume fluid, and a controllable valve configured to selectively control the flow of fluid through said at least one outlet, said valve configured to suspend the indicator release device to increase the concentration of indicator molecules in the volume of fluid in the indicator chamber, wherein the method includes creating a transient in the produced stream to release at least one indicator from said at least one indicator release device, and sampling at a location downstream of tracer sources after creating a transient in the produced stream. 26. A system for monitoring the influx of fluid into a hydrocarbon production well, comprising: at least one probe and at least one indicator release device configured to be connected to the production string, wherein said at least one indicator release device comprises at least one outlet, at least one indicator chamber in fluid communication with said at least one outlet, indicator material located in the indicator chamber, and at least one valve configured to selectively control the flow of fluid through said at least one outlet. 27. The system of claim 26, wherein said at least one probe is a sampling probe, a sensor probe for detecting an indicator, and/or a sensor probe for detecting an indicator in real time.

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