RU2273727C2 - Oil well and oil well bore operational method - Google Patents

Abstract

FIELD: oil wells, particularly to transmit control signal and power signal over well bore during gaslift well operation.

SUBSTANCE: oil well comprises bore and electroconductive pipeline system. Time-variable signal is applied to one section of pipeline system. At least one electronic unit is electrically linked to pipeline system section above impedance coil concentrically arranged from outer part of the pipeline system section in immediate proximity thereto. The impedance coil is chosen so that the impedance coil works as series impedance on power supply frequencies and in frequency band of communication path for electric signal transmitted over above pipeline system section. Above electric signal is received in wireless way by electronic units to regulate operation of at least one electronic unit. Electronic units may be formed as pilot-controlled valves or sensors. Well may include a number of electronic units each adapted to generate and receive communication signals to establish communication with another electronic units in different well sections.

EFFECT: increased quality of well operation.

13 cl, 8 dwg

Description

BACKGROUND OF THE INVENTION

1. The technical field to which the invention relates.

The present invention relates generally to a communication system for an oil or gas well having downhole devices for monitoring and regulating well operation, and in particular, to a communication system having a two-way telemetry backbone communication line with redundant backup followers, sensors and controlled valves.

2. Description of the Related Art

Gas-operated oil wells (gas lift wells) have been used since the 1800s and have proved to be particularly useful in increasing effective oil production where natural reservoir recovery is insufficient (see works by Brown, Connolizo and Robertson ) “A Short Course on Oil Rises in West Texas” and by H.W. Winkler (HWWinkler Review of Undervalued or Missed Gas-Lift Devices and Equipment, SPE, p. 351 (1994)). As a rule, in an oil gas lift well, the natural gas generated in the oil field is compressed and introduced into the annular space between the casing and the lift pipe and sent from the casing to the lift pipe in order to ensure that the lift column of the lift pipe is “lifted” for production oil from the elevator pipe. Although the elevator pipe can be used to introduce gas used for gas lift, and the annular space used for oil production, this has rarely been applied in practice. Initially, gas was simply injected into gas lift wells at the base of the elevator pipe, but for deep wells, excessively high pressures are required to deliver oil. Later, methods were developed for introducing gas into the elevator pipe at various depths in the wells to avoid some of the problems associated with high pressures for oil delivery (see US Patent No. 5267469).

The most common type of gas lift wells use mechanical bellows type gas lift valves attached to the elevator pipe to control the gas flow from the annular space to the elevator string (see US Pat. Nos. 5,772,261 and 5,425,425). In a typical bellows-type gas lift valve, the bellows are pre-installed or charged to some pre-charge pressure, such that the valve allows gas to flow from the annular space and into the lift pipe under pre-charge pressure. The charging pressure of each valve is chosen by the borehole engineer depending on the location of the valve in the borehole, hydrostatic head, the physical condition of the borehole, and many other factors, some of which are suspected or unknown, or change during the life of the borehole.

Some problems are common to bellows type gas lift valves. Firstly, the bellows often loses its pre-charge, leading to a malfunction of the valve in the closed position or changing its set operating value to a different one from the design set value. And sometimes, exposure to excessive pressure can cause the valve to close and become inoperative. Another common malfunction is erosion around the valve seat and wear on the ball rod in the valve. This often leads to partial failure or at least to inefficient production. Since gas ejection through the gas lift valve is often not long in steady state, but rather shows a certain amount of shock and vibration when the valve quickly opens and closes, a gradual deterioration of the valve’s properties usually occurs, leading to a valve leakage. Failure or ineffective operation of bellows-type valves leads to corresponding inefficiencies in the operation of a typical gas-lift well. In fact, it is estimated that the well production is at least 5-15% less than the optimal value due to failures or operational inefficiency of the valves. This cannot be fixed, since the preset pressure of the valve is determined during the design period, and there is not enough operational knowledge of the operating condition of the well to control, prevent, or control instability during production.

Eccentric chambers for gas lift valves are known that are associated with an elevator column and are designed to receive gas lift valves installed and removed by means of hoist ropes. Many gas lift wells include gas lift valves as an integral part of the lift string, which are usually mounted on pipe sections. However, eccentric chambers for gas lift valves, in which replacement is carried out using hoist ropes, such as those manufactured by Camco or Weatherford, have many advantages and are not uncommon (see US Pat. Nos. 5782261 and 5797453). Gas-lift valves placed in an eccentric chamber for gas-lift valves can be inserted and removed using a hoist rope and a lifting tool when inserted either at the apex or at the base. In lateral and horizontal boreholes, a spiral-wound lift pipe is used to introduce and remove gas lift valves. When producing in an oil field, it is common practice to shut off the well every three to five years and use a hoist rope to replace gas lift valves. However, the operator often cannot well assess which valves in the well are malfunctioning or degraded and need to be replaced.

Therefore, it would be a significant advantage to develop a system and method that overcomes the disadvantage of the inefficiency of conventional bellows type gas lift valves. Several methods have been invented for placing controlled valves in a well on an elevator string, but all such known devices typically use an electric cable running along the elevator string to provide power and communication with gas lift valves. This, of course, is extremely undesirable and in practice it is difficult to use a cable laid along the elevator string either at the same time as the elevator string or separately from it, in the annular gap between the elevator string and the casing, due to a number of failure mechanisms present in such a system. The use of cable presents difficulties for well operators when assembling and introducing an elevator string into the wellbore. In addition, the cable undergoes corrosion and intense wear due to the movement of the lift string inside the wellbore. An example of a downhole communication system using cable is shown in PCT / EP 97/01621.

US Pat. No. 4,839,644 describes a method and system for wireless two-way communication in a cased borehole having an elevator string. However, this system describes a communication circuit designed to supply electromagnetic energy in a magnetic wave (H-wave) mode by using the annular space between the casing and the elevator pipe. This requires that the toroidal antenna excite or receive signals in the H-wave mode, the patent proposes the need for an isolated wellhead and does not mention the power source for the module in the well. Inductive coupling requires a substantially non-conductive fluid, such as crude oil, in the annular space between the casing and the elevator pipe, and this oil must have a higher density than the brine so that the leaking brine does not collect at the bottom of the annular space. The invention described in US Pat. No. 4,839,644 has not been widely used as a practical downhole communication scheme because it is expensive, has problems with brine seeping into the casing, and is difficult to use. Another downhole communication system using telemetry using a water-pulse communication channel is described in US Pat. Nos. 4,648,471 and 5,887,657. Although telemetry using a water-pulse communication channel can be successful at low data rates, it has limited applicability where high data rates or where it is undesirable to have sophisticated downhole telemetry equipment via a hydro-pulse communication channel. Other communication methods within the borehole are described in US patent No. 4468665; 4,578,675; 4,739,325; 5,130,706; 5,467,083; 5,493,288; 5,574,374; 5576703 and 5883516. PCT application WO 93/26115 describes a communication system for use in subsea pipelines, which suffers from the need to provide a plurality of power sources in the pipeline.

Consequently, significant progress can be achieved in the operation of gas-lift wells if an alternative is provided to a conventional bellows-type valve, in particular, if the elevator and casing can be used as communication and electrical conductors for controlling and operating a controlled gas-lift valve.

An oil well and the method according to the preamble of claims 1 and 5 of the claims are known from European patent application EP 721053. In the known device and method, the tubular element coated with an electrical insulation coating is used in combination with inductive coils that are located outside the coating to transmit electricity and signals along the tubular element of the well.

European patent application EP 0 964 134 discloses a method in which electrical signals are transmitted through a string of tubular elements of a well, which are also provided with an electrical insulating coating and are electrically isolated from other parts of the tubular string by insulating couplings.

The disadvantage of the known systems is that they include transmitting signals along the tubular elements of the well covered with an electrical insulating layer, which is expensive and prone to wear and damage during installation and use.

SUMMARY OF THE INVENTION

An oil well and the method in accordance with the present invention are distinguished by the distinguishing features of claims 1 and 9 of the claims. In an important application, the oil well is a controllable gas-lift well that includes a cased-hole piping system having an elevator located and extending longitudinally inside the casing. The location of the tubing inside the casing forms an annular space between the tubing and the casing. A communication system, or trunk line, is provided to supply electric power and communication signals to the well. The electric power is preferably low voltage alternating current at ordinary industrial frequencies in the range of 50 to 400 Hz, but in some embodiments, direct current electric power can be used.

In a preferred embodiment of the present invention, an inductance choke (electric choke) of ferromagnetic material lowered into the well is located on the elevator string in the well to act as a series impedance for the current flowing through the elevator pipe. The suspension device for suspending the lift string inside the wellbore includes an insulated portion that electrically isolates the top of the lift string near the surface of the well. The communication is preferably carried out over an electrically insulated section of the elevator column between the insulated portion of the suspension device and the deflated ferromagnetic choke. Electricity and communication signals are transmitted to an electrically isolated section of the elevator string, and the casing acts as an electrical return wire.

Many downhole devices are connected to an elevator string in the well to monitor and control the operation of the well. These downhole devices may include controlled gas lift valves, sensors, electronic modules, and modems. A controlled gas lift valve is connected to the elevator pipe to control gas injection between the inner and outer parts of the elevator pipe, more specifically between the annular space and the inner part of the elevator pipe. A controlled gas lift valve is energized and controlled from the surface to control fluid communication between the annular space and the inside of the lift pipe. Sensors are located in the borehole to monitor the borehole physical state of the borehole. The electronic module is a control unit that receives signals from sensors to communicate signals to the surface and receives communication signals from the surface to control a controlled gas lift valve. Modems are used to exchange signals between other downhole devices and the surface.

In more detail, a computer with a modem located on the surface transmits a communication signal to the elevator pipe, and the signal is received by a modem located in the well. A downhole modem, which is often a component of an electronic module, then transmits a signal to a controlled gas lift valve. Similarly, a downhole modem can receive and then report sensor information to a surface computer. Depending on the communication range that the modems are capable of providing under certain conditions of the well, signals passing through the elevator string can be transmitted between the modems located in the well. Electricity is supplied to the elevator string and received in the well to control the operation of a controlled gas lift valve.

The surface-mounted computer is preferably connected through a surface-mounted modem and an elevator pipe to modems located in the well. A computer located on the surface can receive measurements from a variety of sources, such as downhole or surface sensors, measurements of oil flow rates, and measurements of the injection of compressed gas into the well (flow and pressure). Using such measurements, the computer can calculate the optimal position of the controlled gas lift valve, more specifically, the optimal amount of gas introduced from the annular space inside the casing through the controlled valve into the lift pipe. Additional improvements are possible, such as controlling the amount of injected compressed gas into the well near the surface, controlling back pressure in the wells, controlling porous fritting or a surfactant injection system for foaming oil, and obtaining production and functioning measurements from various other wells in the same field, with the goal of optimizing production in the field.

The ability to actively monitor the current state of the well associated with the ability to control the state on the surface and in the well in a gas lift well has many advantages. Gas lift wells have four main modes of fluid flow, for example foamy (aerated), Taylor, cork and annular flow. The downhole sensors of the present invention make it possible to detect and identify a flow pattern. The aforementioned control mechanisms are a surface-mounted computer, controlled valves, gas inlet, surfactant injection, etc. - provide the opportunity to achieve and maintain optimal flow. In general, well testing and diagnostics can be performed and analyzed continuously and in real time.

In one aspect of the present invention, there is provided an oil well having a wellbore (11) extending into the ground and an electrically conductive piping system (26) located in the wellbore (11) in which one or more devices (50) are electrically connected to the system (26) pipelines in the wellbore for wirelessly receiving a time-varying electrical signal applied to the piping system (26), and at least one device (50) for reading or controlling a physical characteristic in the wellbore us, or in close proximity to the actuated signal, and wherein the electric throttle is in the vicinity of the portion of the piping system for tracing time-varying signal within the piping system; characterized in that the electric inductor (42) is configured to act as a series impedance for the electric current flowing through said portion of the piping system (26), and that at least one device (50) is electrically connected to the piping system ( 26) above the electric inductor (42).

In another aspect of the present invention, there is provided an oil well in which the piping system (26) is an operational lift string (26) which is surrounded by a fluid-filled annular space (31) and a casing (24).

In another aspect of the present invention, there is provided an oil well in which a computer and / or power source (44) is configured to apply a time-varying electrical signal to a piping system for transmitting information.

In another aspect of the present invention, there is provided an oil well in which the device is a sensor for sensing a physical characteristic in a wellbore, such as temperature, pressure or acoustic characteristic.

In another aspect of the present invention, there is provided an oil well in which the device is a valve configured to operate upon receipt of a command using a wireless signal applied to a piping system.

In another aspect of the present invention, there is provided an oil well in which the oil well is a gas lift well, the piping system includes an elevator pipe, and one device is a gas lift valve connected to the elevator pipe and controlled to adjust fluid flow between internal and external part of the elevator pipe.

In another aspect of the present invention, there is provided an oil well comprising a plurality of devices, each of which is configured to send and receive communication signals to communicate with other devices in various areas of the well.

In another aspect of the present invention, there is provided an oil well including a controller and some of the devices that are sensors, and at least one device that is a valve, whereby the action of the valve is determined by the controller based on the input from the sensors.

In an oil well having a wellbore extending into the ground and an electrical conductive piping system located in the wellbore, a method for operating a wellbore by applying a time-varying electrical signal to a piping system that receives one or more wireless devices electrically connected to the system pipelines in the wellbore to influence the operation of at least one device in the ground, and in which the electric inductor is located in osredstvennoy proximity to a portion of the piping system for tracing time-varying signal within the piping system; characterized in that the electric inductor (42) acts as a series impedance for the electric current flowing through said portion of the piping system (26), and that at least one device (50) is electrically connected to the piping system (26) above the electric throttle (42).

In another aspect of the present invention, there is provided a method in which at least one device (50) is a sensor for sensing a physical characteristic in a wellbore, the method including sensing said physical characteristic, such as temperature, pressure or acoustic data, and transmitting perceived physical characteristics of the piping system.

In another aspect of the present invention, there is provided a method in which a time-varying power signal and a time-varying communication signal are applied to a piping system and transmit power and communicate with a plurality of devices.

In another aspect of the present invention, there is provided a method in which the oil well is a gas lift well and the at least one device is a controlled valve, which communicates with the valve and controls the flow of fluid through the valve.

In another aspect of the present invention, there is provided a method comprising controlling the injection of gas lift gas and / or the rate of delivery of crude oil in a gas lift well.

Brief Description of the Drawings

Figure 1 is a schematic front view of a controllable gas lift well according to one embodiment of the present invention, wherein the gas lift well has an elevator and a casing located inside the well.

Fig. 2A is an enlarged vertical part with a partially cut-out elevator string in a cased borehole having an induction choke around the elevator pipe.

Figv is an enlarged horizontal part with a partial cutaway elevator columns figa.

3A and 3B are front sectional views of a controlled valve in a cell configuration in accordance with one embodiment of the present invention.

FIG. 4 is an enlarged schematic front view of the elevator string and casing of FIG. 1, where the elevator string has an electronic module, sensors, and a controlled gas lift valve operatively connected to the exterior of the elevator string.

FIG. 5 is an equivalent circuit diagram for a controlled gas lift well of FIG. 1, where the gas lift well has an AC power source, an electronic module of FIG. 3A, and an electronic module of FIG. 4.

6 is a block diagram of an electronic module system.

DETAILED DESCRIPTION OF THE INVENTION

The term "piping system", as used in this application, can be one single pipe, lift, casing, piston rod, a number of connected pipes, rods, rails, trusses, grids, supports, a branch or side extension of a well, a network of connected pipes or other systems known to those skilled in the art. In a preferred embodiment, the invention is used in the context of an oil well, where the piping system comprises a tubular, metal, conductive pipe or lift columns, but the invention is not limited to this. For the present invention, at least part of the piping system must be electrically conductive so that the electrically conductive portion can constitute the entire piping system (e.g., steel pipes, copper pipes) or the longitudinally extending electrically conductive portion combined with the longitudinally extending non-conducting portion. In other words, the electrically conductive piping system is a system that provides an electrically conductive path from a first location where the power source is electrically connected to a second location at which the device and / or electrical return wire are electrically connected. The piping system is usually a regular round metal elevator pipe, but the cross-sectional geometry of the piping system, or any part thereof, can vary in shape (e.g., round, rectangular, square, oval) and size (e.g., in length, diameter, wall thickness) in any part of the piping system. Therefore, the piping system must have an electrically conductive portion extending from a first location of the piping system to a second location of the piping system.

A “valve” is any device that operates to control fluid flow. Examples of valves include, but are not limited to, bellows type gas lift valves and controllable gas lift valves, each of which can be used to control the flow of gas used for gas lift to the well string. The internal functioning of the valves can vary greatly, and this application should not be limited to the valves described in any particular configuration while the valve is functioning to control flow. Some of the various types of flow control mechanisms include, but are not limited to, ball valve configurations, needle valve configurations, shutoff valve configurations, and cage valve configurations. The valve installation methods discussed in this application can vary widely. Valves can be installed in the well in many different ways, some of which include elevator-mounted configurations of the elevator pipe, eccentric chamber configurations for installing the valves, or permanent mounting configurations, such as mounting the valve in an enlarged elevator manifold.

The term "modem" is used here generally to refer to any communication device designed to transmit and / or receive electrical communication signals through an electrical conductor (eg, metal). Therefore, this term is not limited to the acronym for modulator (device that converts a speech or information signal into a form that can be transmitted) / demodulator (device that restores the original signal after it is modulated by a high-frequency carrier). In addition, the term “modem”, as used here, is not limited to conventional computer modems that convert digital signals to analog signals and vice versa (for example, to send digital information signals over an analogue public switched telephone network). For example, if a sensor sends measurements in an analog format, then such measurements may only need to be modulated with a carrier signal and transmitted, and therefore, analog-to-digital conversion is not required. As another example, only a relay modem or communication device may be required to identify, filter, amplify and / or relay the received signal. However, the modems used in this invention can generally be digital, broadband, as they are widely available from commercial sources and have the broadest applicability.

The term “wireless” as used in the present invention means the absence of conventional, insulated wires, for example, extending from a device located in the well to the surface. The use of an elevator pipe and / or casing as a conductor is considered “wireless”.

The term “sensor,” as used herein, refers to any device that detects, detects, monitors, records, or otherwise reads an absolute value or a change in a physical quantity. The sensors, as described in this application, can be used to measure temperature, pressure (both absolute and different), volumetric flow rate, seismic data, acoustic data, pH (pH), mineralization levels, valve positions, or almost any other physical data.

The term "electronic module" in this application refers to a control device. Electronic modules can have many configurations and can be installed in the well using many different methods. In one installation configuration, the electronic module is actually located inside the valve and provides control of the engine inside the valve. Electronic modules can also be installed externally on any particular valve. Some electronic modules are installed inside eccentric chambers for gas lift valves or enlarged pockets of the elevator pipe, while others can be permanently attached to the elevator string. Electronic modules are often electrically connected to sensors and help in transmitting sensor information to the surface of the well. It is possible that the sensors associated with a particular electronic module can even be placed inside the electronic module. Finally, the electronic module is often closely connected with the modem and can actually contain it, for receiving, sending and transmitting messages from and to the well surface. The signals that are received from the surface by the electronic module are often used to make changes inside the well-controlled devices, such as valves. The signals sent or transmitted to the surface by the electronic module generally contain information about the relative physical conditions of the well provided by the sensors.

The terms "up", "down", "above", "below", as used in this invention, are relative terms to indicate the position and direction of movement and describe the location "along the depth of the well", as is commonly accepted in industry. In deviated or horizontal wells, these terms may or may not correspond to the absolute relative position relative to the surface of the earth.

Consider figure 1, which illustrates an oil well in accordance with the present invention. An oil well is a gas lift well 10 having a wellbore 11 extending from a surface 12 into a production zone 14, which is located at the base of the well. The production platform 20 is located at the surface 12 and includes a suspension device 22 for supporting the casing 24 and the lift string 26. The casing 24 is of the type traditionally used in the oil and gas industry. The casing 24 is usually installed in sections and cemented with cement in the wellbore 11 at the time of completion of the well. The lift string 26, also called a tubing string, is generally a common string containing a plurality of elongated tubular pipe sections connected by threaded joints at each end of the pipe sections, but, alternatively, it can be inserted continuously, for example, as pipes in coils . The production platform 20 also includes a gas inlet throttle 30 for controlling the injection of compressed gas into the annular space 31 between the casing 24 and the tubing 26. Conversely, the exhaust valve 32 allows oil and gas bubbles to be forced out of the interior of the tubing 26 during production oil.

The gas lift well 10 includes a communication system 34 for providing electric power and a two-way downhole communication in the well 10. The communication system 34 includes a deflated ferromagnetic choke 42 that is mounted on the lift string 26 to act as a series impedance for electric current. The size and material of the ferromagnetic inductor 42 can be changed in order to change the magnitude of the series impedance. The suspension device 22 includes an insulated portion 40 that electrically isolates the elevator string 26 from the casing 24 and from the rest of the elevator string located above surface 12. The elevator string section 26 between the insulated portion 40 and the deflated choke 42 can be considered as a power supply channel and communication (see also figure 5). The deflated choke 42 is made of high magnetic permeability material and is mounted concentrically and on the outside of the lift column 26. The choke 42 is usually insulated by packing in a plastic shrink film and can be reinforced with epoxy to resist rough handling.

A computer and a power source 44, which have power and communication lines 46, are located outside the wellbore 11 on the surface 12. Communication lines 46 pass through a pressure supply line 47 located in the suspension device 22 and are electrically connected to the elevator column 26 below the insulated section 40 of the suspension device 22. Electricity and communication signals are supplied to the elevator column 26 from the computer and the power source 44.

2A and 2B, in which the inductor 42 comprises a toroidal core located concentrically with the elevator string 26 and inside the annular space 31 between the elevator string 26 and the casing 24. The inductor 42 functions to create an anti-electromotive force in the elevator string 26, which counteracts the electromotive force (emf) from the power source 44. The counter-electromotive force is created by changes in the flux of magnetic induction in the inductor, and in accordance with the law of electromagnetic Faraday induction this emf is proportional and the magnitude of the flux of magnetic induction and its rate of change over time. When the pipe sections above the insulated portion 40 and below the deflated choke 42 are grounded, the counter-electromotive force induced by the deflated choke 42 counteracts the transmission of electricity and communication signals in a time-varying current through the choke 42. This effectively forms an insulated section of the elevator pipe between the insulated part 40 and the deflated the inductor 42. When the design of the inductor creates a significant degree of isolation, the anti-electromotive force is close to the magnitude of the applied emf. For the extent that the anti-electromotive force is less than the applied emf, the difference between the two forces allows the leakage current to flow through the throttle section of the elevator pipe. This energy is lost, but is required for the operation of the inductor, because the magnetic flux from this leakage current passes through the inductor, which creates a counter-electromotive force in the inductor section. Thus, the purpose of the design is to create an electric inductor that produces a counter electromotive force from the leakage current as efficiently as possible.

On figa and 2B shows the basic design of the throttle and shows the variables used in the analysis of the design. Defining variables and a self-consistent set of physical units are:

L - throttle length, meters;

a - internal radius of the throttle, meters;

b is the outer radius of the throttle, meters;

r is the distance from the axis of the throttle, meters;

I is the rms value of the leakage current through the chimney section of the pipe, amperes;

ω is the angular frequency of the leakage current, radians per second; and

μ is the absolute magnetic permeability of the throttle material at a radius r, Henry per meter.

By definition, ω = 2πf, where f is the frequency in hertz. At a distance r from the leakage current (I), the rms value of the magnetic field in free space (N), in amperes per meter, is determined by the expression:

H = I / 2πr.

The magnetic field (H) is axially symmetric with respect to the axis of the throttle, and it can be visualized in the form of magnetic lines of force forming circles around this axis.

For a point inside the inductor material, the rms value of the magnetic field (B), in tesla (weber per square meter), is determined by the expression:

B = μH = μI / 2πr.

The rms value of the flux of magnetic induction (F), enclosed inside the body of the inductor, in Weber, is determined by the expression:

F = ∫B dS

where S is the cross-sectional area of the throttle in square meters, as shown in FIG. 2A, and integration is performed over area S. Integration from the inner radius of the throttle (a) to the outer radius of the throttle (b) along the length of the throttle (L) provides:

F = μLI ln (b / a) / 2π

where ln is the function of the natural logarithm. The voltage of the anti-electromotive force generated by the magnetic flux (F), in volts, is determined by the expression:

V = ωF = 2πf F = μLIf ln (b / a).

It should be noted that the anti-electromotive force (V) is directly proportional to the length (L) of the inductor for constant values a and b, the inner and outer radii of the ferrite element. Thus, by varying the length (L) of the inductor, any required anti-electromotive force (V) can be generated for a given leakage current (I).

Electricity can be transmitted in a certain frequency range within the functional frequency band, and communication signals can be transmitted in a different frequency range within the same functional frequency band. Since the frequency of the AC power is generally lower than the frequency of the provided communication frequency band, the frequency of the AC power often defines the lower limit of the frequency range above which electrical isolation is required. Since the electrical impedance of the inductor rises linearly with frequency, if the inductor provides the corresponding impedance at the AC power frequency, it will usually also be suitable at the higher frequencies used for communication. However, ferromagnetic materials have a maximum operating frequency above which ferromagnetic properties are not demonstrated. Thus, the upper frequency boundary of the ferromagnetic material selected for the design of the inductor must be suitable to provide isolation at the upper boundary of the frequency band of the communication channel.

The method of electrical isolation of the section of the elevator column, as shown in figure 1, is not the only way to provide electricity and communication signals for the well. Instead of using a suspension device 22 with an insulated portion 40, an upper ferromagnetic inductor (not shown) can be arranged around the elevator column 26. Similarly, instead of a deflated ferromagnetic choke 42, an electrical insulating connector can be used in the well. In the preferred embodiment shown in FIG. 1, electric power and communication signals are supplied to the elevator string 26 with an electrical return wire provided by the casing 24. Instead, the electrical return wire could be provided by grounding through earth. An electrical connection to ground through the earth can be provided by passing the wire through the casing 24 or by connecting the wire to the lift string below the deflated choke 42 (if the bottom of the lift string is grounded).

An alternative electricity and communication channel can be provided using casing 24. In a configuration similar to that used with the riser 26, part of the casing 24 can be electrically isolated to provide a communication backbone for transmitting electricity and communication signals to the well. If ferromagnetic chokes are used to isolate portions of the casing, the chokes can be arranged concentrically around the outside of the casing. Instead of using chokes with casing 24, electrical insulating connectors can be used similar to the insulated portion 40 of the suspension device 22. In embodiments using the casing 24 to supply electric power and communication signals to the well, the electrical return wire can be provided either via an elevator string 26 or grounding through earth.

A packer 48 is placed inside the casing 24 in the well beneath the deflated choke 42. The packer 48 is located above the production zone 14 and provides hydraulic isolation between the production zone 14 and the well space above it. The packer electrically connects the metal lift string 26 to the metal casing 24. Typically, the electrical connection between the lift string 26 and the casing 24 does not allow the transmission or reception of electrical signals up and down the bore 11 of the well using the lift string 26 as one conductor, and casing 24 as another conductor. However, the placement of the insulated portion 40 and the deflated ferromagnetic choke 42 creates an electrically isolated section of the elevator string 26, which provides a system and method for transmitting electricity and communication signals up and down the bore 11 of the gas lift well 10.

Referring again to FIG. 1, it is noted that between the insulated portion 40 and the deflated ferromagnetic choke 42, a plurality of downhole devices 50 are electrically connected to the elevator string 26. Some of the downhole devices 50 include controllable gas lift valves. Other downhole devices 50 may include electronic modules, sensors, communication devices (usually broadband digital modems) or conventional valves. Although the transmission of electricity and communication signals takes place over an electrically isolated section of the elevator string, downhole devices 50 may be mechanically connected above or below a deflated choke 42.

Consider FIGS. 3A and 3B, which illustrate in more detail the installation of one of the downhole devices (similar to downhole devices 50 in FIG. 1). As mentioned above, conventional bellows-type gas lift valves are often used in gas lift wells to inject pressurized gas from the annular space 31 into the interior of the lift string 26. In the present invention, any or all of the conventional valves can be replaced by controlled gas lift valves. 3A and 3B show a control valve 220 according to the present invention. The control valve 220 includes a housing 222 and is slidably inserted into the eccentric chamber 224 for gas lift valves. The eccentric chamber 224 for gas lift valves includes a housing 226 having a gas inlet port 228 and a gas outlet port 230. When the control valve 220 is in the open position, the gas inlet 228 and the gas outlet 230 provide fluid communication between the annular space 31 and the interior of the lift column 26. In the closed position, the controlled valve 220 prevents fluid communication between the annular space 31 and the inside of the elevator column 26. In the numerous intermediate positions between the open and closed positions, the controlled valve 220 measures the amount of gas flowing from the annular anstva 31 in tubing 26 through inlet port 228 and gas outlet port 230 for the gas.

A stepper motor 234 is located inside the housing 222 of the controlled valve 220 for rotating the gear 236. The gear 236 engages the worm gear 238, which, in turn, raises and lowers the cage 240. When the valve 220 is in the closed position, the cage 240 engages the seat 242 to prevent flow into the opening 244, thereby preventing leakage into the valve 220. It is believed that this configuration of the cell valve is a preferred design from the point of view of hydromechanics compared to an alternative embodiment onfiguratsii needle valve. More specifically, the flow of fluid from the inlet port 228 past the cage and seat connection (240, 242) allows precise control of the fluid flow without excessive wear due to the fluid of the mechanical interface. Those skilled in the art will appreciate that needle valve designs or other valve designs can be used.

The control valve 220 includes a shut-off valve head 250 located inside the housing 222 below the cage 240. The inlet 252 and the outlet 254 cooperate with the gas inlet 228 and gas outlet 230 when the valve 220 is in the open position to provide fluid communication between the annular space 31 and the interior of the elevator column 26. The shut-off valve head 250 ensures that fluid flows only when the fluid pressure in the annular space 31 p greater than the operation pressure of the fluid in the interior of the tubing 26.

An electronic module 256 is located inside the body of the controlled valve 220. The electronic module 256 is operatively connected to the valve 220 to communicate between the surface of the well and the valve. The electronic module 256 comprises a spread spectrum communication device for receiving electric power and transmitting messages to the elevator column 26, as described above. In addition to sending signals to the surface to report a physical condition in the well, the electronic module can receive commands from the surface and adjust the performance of valve 220.

The valve 220 is physically located below the deflected throttle 42, but is electrically connected to the elevator string 26 above the throttle 42 using a hinged conductor 64. A ground wire 66 is electrically connected between the valve 220 and the centralizer 60 with coil springs to provide an electrical return wire for the valve 220. Centralizer 60 with coil springs is used to center the elevator string 26 relative to the casing 24. When located in an electrically isolated section of the elevator string 26, each centralizer 60 with piralnymi springs includes PVC insulators 62 out to provide electrical insulation casing 24 from the tubing 26.

Consider figure 4, which illustrates an alternative installation of several downhole devices (similar to downhole devices 50 in figure 1). The elevator string 26 includes an enlarged ring-shaped pocket, or a manifold 100 formed on the outside of the elevator string 26. The enlarged pocket 100 includes a housing that surrounds and protects the gas-operated valve 99 (shown schematically) and an electronic module 106. B In this mounting configuration, the gas lift valve 9.9 and the electronic module 106 are rigidly attached to the lift column 26 and cannot be inserted and removed using the hoist rope. Alternatively, the valve 99 and the electronic module 106 can be located in an eccentric valve installation chamber (not shown) so that the devices can be easily inserted and removed using a wire rope. The ground wire 102 (similar to ground wire 66 in FIG. 3B) is fed through an enlarged pocket 100 to connect the electronic module 106 to the centralizer 60 with coil springs, which is grounded to the casing 24. The electronic module 106 is external to the valve 99 and is rigidly attached to the elevator a column 26 for receiving communication signals and electric power via a hinged conductor 104 of electric power and signals.

The controllable valve 99 includes an electric cage valve head 108 and a shut-off valve head 110, which are shown schematically in FIG. 4. The cell valve head 108 and the shut-off valve head 110 operate in a manner similar to that of the cell 240 and the shut-off valve head 250 of FIG. 3A. The valve heads 108, 110 cooperate to control fluid communication between the annular space 31 and the interior of the elevator column 26.

Together with the electronic module 106, many sensors are used to control the operation of the controlled valve 99 and the gas lift well 10. Pressure sensors, such as those manufactured by Three Measurements Specialties, Inc., can be used to measure the internal pressure of the elevator pipe, the internal pressure of the manifold body, and the pressure drops gas lift valves. In industrial operation, the internal pressure of the reservoir is considered unnecessary. The pressure sensor 112 is rigidly attached to the elevator string 26 to read the internal pressure of the fluid elevator pipe within the elevator column 26. A pressure sensor 118 is installed inside the pocket 100 to detect a differential pressure in the cell valve head 108. Both the pressure sensor 112 and the pressure sensor 118 are independently electrically connected to the electronic module 106 for receiving electric power and for transmitting communication signals. Pressure sensors 112, 118 are mounted in the manifold to withstand severe vibration associated with the gas lift columns.

Temperature sensors, such as manufactured by Four Analog Devices, Inc. (e.g. LM-34) are used to measure the temperature of a fluid inside an elevator pipe, housing manifold, power transformer, or power source. The temperature sensor 114 is attached to the elevator column 26 to read the internal temperature of the fluid inside the elevator column 26. The temperature sensor 114 is electrically connected to an electronic module 106, which receives electric power and transmits communication signals. The temperature transmitters used in the well have a nominal range of -50 to 300 ° F (Fahrenheit) and are air-conditioned via an input circuit of +5 to + 255 ° F. The raw voltage generated at the power source in the electronic module 106 is divided into a resistive voltage divider element so that 25.5 V produces an input signal for an analog-to-digital converter of 5 V.

The mineralization sensor 116 is also electrically connected to the electronic module 106. The mineralization sensor 116 is rigidly and hermetically connected to the housing of the enlarged pocket 100 for sensing the mineralization of the fluid in the annular space 31.

It should be understood that the alternative embodiments illustrated in FIGS. 3B and 4 may include or exclude any number of sensors 112, 114, 116 or 118. Sensors other than those shown may also be used in any of the embodiments. These may include gauge pressure sensors, absolute pressure sensors, differential pressure sensors, volumetric flow rate sensors, elevator acoustic wave sensors, valve position sensors, or many other analog signal sensors. Similarly, it should be noted that although the electronic module 256 shown in FIG. 3B is located inside the valve 220, an electronic module similar to the electronic module 106 can be placed with various sensors and used independently of the controlled valve 220.

We now consider FIG. 5, which shows an equivalent circuit diagram for a gas lift well 10, and compare it with FIG. The computer and power supply 44 include an AC power source 120 and a modem 122 electrically connected between the casing 24 and the riser 26. As discussed above, the electronic module 256 is internally mounted in a valve body that can be inserted and removed from the well with using hoisting ropes. The electronic module 106 is independently and permanently mounted in an enlarged pocket on the elevator column 26.

For the purposes of the equivalent circuitry of FIG. 5, it is important to note that the electronic modules 256, 106 seem identical, both modules 256, 106 are electrically connected between the casing 24 and the riser 26. The electronic modules 256, 106 may or may not contain various components and combinations, such as sensors 112, 114, 116, 118. In addition, electronic modules may or may not be an integral part of the controlled valve. Each electronic module includes a power transformer 124 and a data converter 128. The data converter 128 is electrically connected to the modem 130.

The computer and power supply 44 also include a surface controller (not shown in FIG. 5) that is electrically connected through a surface communication device (e.g., modem 122) and an elevator string 26 and / or casing 24 to a communication device in the well (e.g. , to the modem 130). Each modem 130 can communicate with modem 122 either directly or by relaying through intermediate communication devices (containing, for example, modems, filters, data converters, amplifiers) to transmit a signal, if necessary, to make changes in the operation of the well. For example, a surface-mounted computer can receive measurements from various sources, such as downhole sensors, oil production measurements, and measurements of the injection of compressed gas into the well (flow and pressure). Using such measurements, the computer can calculate the optimal position of the controlled gas valve, more specifically the optimal amount of gas introduced from the annular space 31 through each controlled valve into the riser 26. The computer can control additional parameters, such as control the amount of compressed gas introduced into the well at the surface , backpressure control in wells, control of porous frying or surfactant injection system for foaming oil, etc. Intimate measurements of production and operation from various other wells in the same field, optimize production in the field or production area.

Depending on the communication range that modems 130 are capable of providing under certain well conditions, transmitting sensor and control data up and down the well may require these signals to be transmitted between modems 130 rather than passing directly from the surface to selected downhole devices 50 (see Fig. 1). This relay method can be applied to both conventional and multilateral well development.

The modems 130 located in the well are preferably arranged so that everyone can communicate with the next two modems up the well and the next two modems down the well. This redundancy allows you to quickly maintain communication even in the event of a failure of one of the modems 130 located in the well.

A set of downhole devices 50, having modems 130, can provide a permanent trunk line, which can be part of the well’s infrastructure. Such a main communication line can provide means for measuring the state in each part of the well and transmit data to a computer located on the surface of a computer or a controller located in the well, and for a computer, transmit control signals to open or close the well valves in order to establish backpressure and establish the injection rate gas, regulation of the volumetric flow rate and so on. This control level allows optimizing production from the well depending on criteria that can be dynamically controlled essentially in real time, rather than being fixed by the purpose of static production. For example, it is optimal, under one set of economic conditions, that the maximum withdrawal from the tank may be, but under other economic conditions it may be advantageous to change the production method by minimizing the cost of extraction, using transport gas (gas used for gas lift) for maximum effect.

Consider figure 6, in which the electronic module 106 is shown in more detail. Although the components of any particular electronic module may vary, the components shown in FIG. 6 may be present in electronic modules placed inside the valve body (such as electronic module 256) or electronic modules that are located outside the valve. Amplifiers and signal conditioners 180 are provided for receiving input signals from various sensors, such as elevator pipe temperature, annular space temperature, elevator pipe pressure, annular space pressure, conveying gas flow rate, valve position, mineralization, differential pressure, acoustic readings and other . Some of these sensors are similar to sensors 112, 114, 116 and 118 shown in FIG. Any low-noise operational amplifiers are preferably configured with non-inverting inputs and unbalanced outputs (e.g. Linear Technology LT1369). All amplifiers 180 are programmed with gain elements designed to convert the operating range of the input signal from a single sensor to a significant 8-bit output signal. For example, an input pressure signal of one psi will produce a digital output signal equal to one bit, 100 degrees of temperature will produce a digital output signal equal to 100 bits, and an input signal 12.3 V of raw DC voltage will produce an output signal equal to 123 bits . Amplifiers 180 are able to perform the operation, forming an output signal with a span equal to the supply voltage.

The electronic module 106 is electrically connected to the modem 122 through the casing 24 and the lift string 26. Address switches 182 are provided to address a specific device from the modem 122. As shown in FIG. 6, 4 address bits can selectively switch to form the upper 4 bits of the full 8 bit address. The lower 4 bits comprise and are used to address the individual elements within each electronic module 106. Thus, when using the illustrated configuration, sixteen modules are assigned to one modem 122 in a single communication line. Based on this configuration, up to four modems 122 can be placed on one communication line.

The electronic module 106 also includes a programmable interface controller (CRI) 170, which preferably has a base frequency of 20 MHz and is configured with 8 analog-to-digital inputs 184 and 4 address inputs 186. The CRP 170 includes a serial transistor-transistor level communication system (TTU), universal asynchronous transceiver UAPP 188, as well as interface 190 of the engine controller. CRP 170 is electrically connected to modem 171 (similar to modem 130 of FIG. 5), which is connected to modem 122.

The electronic module 106 also includes a power source 166. A power supply bus of a nominal voltage of 6 V AC is connected to the power supply 166 via an elevator column 26. A power supply 166 converts this electricity to a voltage of plus 5 V DC at terminal 192, minus 5 V DC at terminal 194 and plus 6 V DC terminal 196. An earth terminal 198 is also shown. Transformed electricity is used by various elements in the electronic module 106.

Although the connections between the power supply 166 and the components of the electronic module 106 are not shown, the power supply 166 is electrically connected to the following components to provide certain power. PKI 170 uses plus 5 VDC, while modem 171 uses plus 5 V and minus 5 VDC. The motor 199 (similar to the stepper motor 234 in FIG. 3A) is supplied with a voltage of plus 6 V DC from terminal 196. The power supply 166 includes a step-up converter for converting a nominal voltage of 6 V AC to a voltage of 7.5 V AC. This 7.5 V AC voltage is then rectified in a half-wave bridge circuit, giving a 9.7 V unregulated DC voltage. Three-terminal regulators provide adjustable output signals at terminals 192, 194, and 196, which are strongly filtered and protected by a reversible emf circuit. Modem 171 is the main consumer of electricity in the electronic module 165 and typically uses 350 + milliamperes with plus / minus 5 V DC for transmission.

Modem 171 is a digital broadband modem having an IC / SS high-frequency communications chipset, such as the EG models ICS1001, ICS1002 and ICS1003 manufactured by National Semiconductor. The 171 modem is capable of operating at data rates of 300-3200 baud at carrier frequencies in the range from 14 kHz to 76 kHz. US patent No. 5488593 describes the chipset in more detail and is incorporated herein by reference. There are alternative implementations of suitable modems based on various transmission principles, both broadband and narrowband, which are commercially available and which are suitable for the purpose of providing two-way communications between modems.

The PKI controller 170 controls the operation of the stepper motor 199 through the controller 200 of the stepper motor, type model SA1042, manufactured by Motorola. The controller 200 only needs directional information and simple clock pulses from the CRI 170 to drive the stepper motor 199. The initial setup of the controller 200 determines all the elements for the initial action in known states. A stepper motor 199, preferably a MicroMo worm head (mechanism head), has a cage valve head 201 (similar to cage 240 in FIG. 3A), which is the main active component of a controlled gas lift valve. The 199 stepper motor provides 0.4 inch ounce torque and can be driven at speeds of up to 500 steps per second. The full revolution of the stepper motor 199 consists of 24 separate steps, and the worm head provides 989: 1 mechanical reduction, providing a maximum speed of 1 revolution per minute on the output shaft of the worm head with 24 in-lb torque, which is more than enough to lower and raise the valve 201. Although this illustrative example of a suitable embodiment is based on the use of a stepper motor, it is important to note that there are alternative methods of electronic control under odyaschie for other types of engines, many of which may be suitable for controlling the opening degree of the valve 201.

A CRP 170 communicates through a digital modem 171 with a modem 122 via a casing 24 and an elevator 26. The CRP 170 uses the MODBUS 584/985 PLC communication protocol. The protocol is encoded for transmission through ASCII (American Standard Code for the Exchange of Information).

Act

For a large fraction of artificially raised produced oil, a gas lift is used today to help deliver oil from the reservoir to the surface. In such gas lift wells, compressed gas is introduced into the well outside the lift pipe, typically into the annular space between the casing and the lift pipe, and mechanical gas lift valves allow gas to penetrate the lift pipe section, thereby inducing an increase in the fluid column inside the lift pipe to the surface. As described above, conventional mechanical gas lift valves are unreliable due to leakage and failure. Such leaks and failures are not easily detected on the surface, and they are likely to reduce the production efficiency from the well by about 15 percent due to lower flow rates and higher requirements for field pressure gas supply systems used for gas lift.

The wireless trunk communication line of the present invention provides a system for monitoring and controlling the operation of a gas lift well. By placing downhole devices, such as sensors, electronic modules, controlled gas lift valves and modems, on the lift string of the well, precise control and changes in the well can be made to increase effective production. Each of the individual downhole devices is individually addressed via wireless communication through the elevator pipe and casing. That is, the surface modem and its associated controller communicate with a plurality of modems located in the well. When a surface modem communicates with a particular modem in the well, other modems in the well may act as intermediates, transmitting signals if necessary. The sensors report such measurements as the pressure of the elevator pipe in the well, the pressure in the casing in the well, the temperature of the elevator pipe and the casing in the well, the volumetric flow rates of the gas used for gas lift, the position of the gas valve and acoustic data (see Fig. 4 , sensors 112, 114, 116 and 118). A computer located on the surface (located either in the wellhead or in the center of the existing field) continuously combines and analyzes well data, as well as data from the surface, in order to calculate the profile of the pressure distribution of the elevator pipe in real time. Based on these data, the optimum volumetric gas lift flow rate for each controlled gas lift valve is calculated. Alternatively, the sensors can communicate their measurements through follower modems located in the well to a controller connected to the gas lift valve in order to similarly control the action of the valve to obtain the optimum or desired volumetric flow rates.

In addition to controlling the volumetric flow rates of the well, production can be controlled to produce optimal fluid flow conditions. Unwanted conditions such as “level rise in the well” and “cork flow” can be avoided. As mentioned above, it is possible to achieve and maintain an optimal flow rate corresponding to the desired current flow rate of the well. Due to the ability to quickly detect unwanted flow conditions in the well, production can be controlled to avoid such unwanted conditions. The computer’s quick detection of flow conditions on the surface allows the computer to correct any flow problems by controlling factors such as the position of the controlled gas lift valve, gas injection rate, back pressure in the elevator pipe near the wellhead, and even the introduction of a surfactant.

Even though many of the examples discussed here are applications of the present invention in oil wells, the present invention can also be applied to other types of wells, including, but not limited to, water wells and natural gas wells.

Specialists in the art should understand that the present invention can be applied in many areas where you want to provide a controlled valve inside an inclined well, a borehole or any other area that is difficult to access. In addition, it will be understood by those skilled in the art that the present invention can be applied in many areas where a conductive piping system already exists and there is a need for tracing electricity and a controlled valve communication system in the same or similar way as the piping system . The water spray system or network in a building to extinguish fires is an example of a piping system that may already exist and may have the same or similar path that is required for electricity tracing and a controlled valve communication system. In this case, another piping system or another part of the same piping system can be used as the electrical return wire.

Claims (13)

1. An oil well having a wellbore extending into the ground and an electrically conductive piping system located in the wellbore, in which one or more electronic modules for reading or controlling a physical characteristic in the wellbore or in close proximity to it are electrically connected to the site piping systems for wirelessly receiving a time-varying electrical signal applied to a portion of a piping system and actuating said signal scrap of at least one of the above-mentioned modules, and having an electric inductor located concentrically from the outside of the pipeline system section in the immediate vicinity of it for tracing a time-varying signal inside the specified section, characterized in that at least one electronic the module is electrically connected to the section of the piping system above the electric inductor, which is configured to act as a series impedance at the transmission frequencies and power and communication channel frequency band of the electrical signal flowing through said conduit portion. 2. The oil well according to claim 1, characterized in that the section of the piping system is a production lift, which is surrounded by a fluid-filled annular space and a casing. 3. The oil well according to claim 1, characterized in that it further comprises a computer and a power source, which are configured to apply a time-varying electrical signal to a portion of the piping system for transmitting information. 4. The oil well according to claim 1, characterized in that the electronic module is a sensor for reading the physical characteristics in the wellbore - temperature, pressure or acoustic characteristics. 5. The oil well according to claim 1, characterized in that the electronic module is a valve configured to operate upon receipt of a signal applied to the piping system. 6. The oil well according to claim 1, characterized in that the oil well is a gas lift well, the piping system includes an elevator pipe, and one electronic module is a controllable gas lift valve connected to the elevator pipe with the possibility of adjusting the fluid flow between the internal and external parts of the elevator pipe. 7. The oil well according to claim 1, characterized in that it contains many electronic modules, each of which is configured to send and receive communication signals for communication with other electronic modules in various areas of the well. 8. An oil well according to any one of claims 1, 4 and 5, characterized in that it contains a controller and some of the modules that are sensors, and at least one electronic module that is a valve, connected in such a way that the action of the valve is determined controller based on input from sensors. 9. A method of operating an oil wellbore having an electrically conductive piping system located in a wellbore extending into the ground, comprising applying a time-varying electrical signal to a portion of a piping system and wirelessly receiving said signal by one or more electronic modules that are electrically connected to a portion of the system pipelines to influence the operation of at least one electronic module, and in which the electric inductor is concentric on the outside of the pipeline system section in close proximity to it for tracing a time-varying signal inside the pipeline system, characterized in that at least one electronic module is electrically connected to the pipe system section above the electric inductor, which is selected so that it acts as a series impedance at the frequencies of the power transmission and in the frequency band of the communication channel of the electrical signal flowing through the said section with piping tem. 10. The method according to claim 9, characterized in that they read the physical characteristic — temperature, pressure or acoustic data — by at least one of the electronic modules, which are the corresponding sensor, and transmit the read physical characteristic over the portion of the piping system. 11. The method according to claim 9, characterized in that a time-varying electrical signal and a time-varying communication signal are applied to a portion of the piping system and transmit electricity and communicate with a plurality of electronic modules. 12. The method according to claim 9, characterized in that the oil well is in the form of a gas-lift oil well and at least one electronic module in the form of a controllable valve is carried out and communication with the valve and regulation of the fluid flow through the valve are performed. 13. The method according to p. 12, characterized in that they control the input of gas-lift gas and / or the flow rate of the gas-lift.

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