RU2589016C1 - Method of determining air-tightness of downhole equipment with dual extraction of fluids from well with sucker-rod and electric-centrifugal pump - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in dual operation of production wells. When determining air-tightness of downhole equipment with dual extraction of fluids from well with sucker-rod pump and electric-centrifugal pump, dynamic level is determined in annular space of upper site, dynamometer chart of sucker-rod pump is measured. Further, method includes measuring operation parameters of electric centrifugal pump with telemetric system, collecting a control sample of fluid from flow line for water content, making sure of good condition and tightness of wellhead equipment, stopping sucker-rod pump of upper site. Then both in lower and upper position of ground drive of sucker-rod pump, performing pressurisation of tubing string with help of electric centrifugal pump of lower site while tracking change of pressure in buffer when operating with a closed valve. After stopping electric centrifugal pump, monitoring readings of operation at control station, in presence of alarm signal "turbine rotation", making a conclusion on drainage of liquid from tubing string and leakiness of check valve of electric centrifugal pump. At identical rate of rise and drop of temperature on buffer of well in different positions of ground drive of sucker-rod pump and pressure drop rate within a range of not more than 2 MPa for 15 minutes, making a conclusion on tightness of switch and tubing string in range of electric centrifugal pump to well head. At rate of increase of pressure on buffer of well in upper position of ground drive of sucker-rod pump below and rate of drop higher than in lower position of drive of sucker-rod pump, making a conclusion of leakage of sealing cup in lock support of switch. If in upper position of ground drive of sucker-rod pump electric centrifugal pump does not develop pressure at well buffer, and in lower develops and there is lifting of liquid level in annular space, then conclusion is made on output of sealing cup of sucker-rod pump from lock support switch. If both in both lower and upper position of ground drive of sucker-rod pump rate of pressure drop on buffer is more 2 MPa for 15 minutes, then conclusion is made on leakage of switch and/or tubing string in range of electric centrifugal pump to well head. Sucker-rod pump and electric-centrifugal pump are then put into operation without stopping sucker-rod pump of upper site, stopping operation of electric centrifugal pump of lower site. Immediately after shutdown of electric centrifugal pump of lower site, fluid level in annulus is monitored, and pressure change is measured periodically under packer based on readings of telemetric system on display panel of controller of control station. At stable increasing in level of liquid, conclusion is made on leakage, and at constant level of liquid, conclusion is made on tightness of packer or section of tubing string from electric centrifugal pump to packer.

EFFECT: determination of tightness of downhole equipment.

1 cl, 2 dwg

Description

The invention relates to the oil industry and can be used for simultaneous and separate operation of production wells.

There is a method of simultaneous and separate operation of a two-layer well, including flushing and patterning of the well, tripping operations with block mounting of downhole equipment and production of well fluid. First, the lower block is lowered, consisting of a funnel, downhole and support packers with a direct-flow coupling, in which tubular elements with sockets of a sliding pipe connection are installed, which are sequentially screwed at the wellhead with tubing and tubing, and lowered using a landing string equipped with valve, benchmark and hydraulic mounting tool, the latter collet is hooked to the inner groove in the outer tubular element with fixing the landing depth leveled by the benchmark, and weight a - using a dynamometer. The second intake of the tubing string into the production string at a certain speed lowers the second block of downhole equipment, consisting of a flow control and fluid metering unit (BRPU) with nipples of tubular elements of a sliding pipe connection, a cable input coupling with a cable connector and an electric centrifugal pump (ESP) with frequency-controlled electric drive connected to a power cable and equipped with a telemetric system (TMS), until the articulation of the sliding pipe connection. The tubing string is sealed with a fitting pipe to the wellhead faceplate, the ends of both cables pass through the faceplate cable entry and the latter is fixed to the production string flange. The cables are sealed in the cable entry of the faceplate and connected to the power point and control panel. The tightness of the packer fit is checked by lowering the static liquid level in the above-packer space of the ESP under the control of the pressure gauge. By changing the frequency of rotation of the ESP by means of a frequency-controlled electric drive and valve positions, the well is put into operation under the control of TMS (RF patent No. 2562641, class E21B 43/14, published on 09/10/2015).

Closest to the proposed invention in technical essence is a method for simultaneously and separately operating a well of multilayer fields, comprising lowering into a well with several layers on a pipe string without or with a plugged lower end of at least mechanical, impulse, support, hydraulic, hydromechanical or packers electric action with or without pipe disconnector. In this case, the packer consists of at least a body, a barrel and a set of cuffs. And the pipe string disconnector consists of at least a housing and a barrel, sealed together by sealing elements, and shear screws. In one embodiment, between the two bottom-hole zones of the strata, two packers are placed in any of the combinations and a bypass element in the form of a borehole chamber or pipe or valve with circulation channels is lowered between them. After simultaneous or separate planting of these packers in the well, their tightness is checked by supplying fluid between the packers through the bypass element by creating excessive pressure in the pipe string. When stopping the flow of fluid, if there is a drop in the value of the latter, take the packers between the layers leaking and at the same time lift them from the well. If the overpressure does not fall, the packers are sealed tight and the well is put into operation. In the second embodiment, a packer with two sets of cuffs is installed, between which circulation channels are made on the trunk and a supporting sleeve with bypass channels is placed on it. Leak test fluid is supplied between two sets of cuffs. In a third embodiment, the pipe string disconnector is installed at least above the packer located between the two bottomhole zones of the formations. At the same time, its trunk is made with at least one or two grooves for shear screws and, accordingly, on the housing, two rows of holes with shear screws are provided. When disconnecting the body from the barrel, two rows of shear screws are cut off sequentially with increasing excess load on the pipe string when the packer or packers are broken (RF patent No. 2380526, class E21B 43/14, publ. 01.27.2010 - prototype).

Known methods do not provide the ability to determine the tightness of downhole equipment during simultaneous-separate production (ORD) of fluids from the well by a sucker rod pump (SHG) and ESP.

The proposed invention solves the problem of determining the tightness of downhole equipment during simultaneous and separate production of fluids from a well SHGN and ESP.

The problem is solved in that in the method for determining the tightness of downhole equipment with fluid pressure from the SHGN and ESP wells, the dynamic level in the annulus of the upper object is determined, the SHGN dynamogram is taken, the operation parameters of the ESP with TMS are taken, a control fluid sample is taken from the flow line to the water cut, make sure in serviceability and tightness of the wellhead fittings, stop the SHGN of the upper object, both in the lower and in the upper position of the ground drive of the SHG, pressure testing of the tubing is carried out using the lower ESP about the object with monitoring the pressure changes on the buffer when working on a closed gate valve, stop the ESP and monitor the operation of the installation at the control station (SU), in the presence of an alarm signal “turbine rotation”, make a conclusion about draining the liquid from the tubing and about the leakage of the ESP check valve , at identical rates of increase and decrease in pressure on the well buffer at different positions of the ground SHG drive and the rate of pressure drop within no more than 2 MPa in 15 minutes, a conclusion is made about the tightness of the switch and the oil reservoir in the interval from the ESP to the wellhead, at a rate of increase in pressure on the wellbuffer in the upper position of the ground drive lower, and the rate of fall higher than in the lower position, make a conclusion about the leakage of the cuff fastening in the castle support of the switch, if in the upper position of the ground drive SHGN The ESP does not develop pressure on the well buffer, but in the lower one it develops and the liquid level rises in the annulus, then they conclude that the cuff fastening of the SHG from the castle support of the switch is released, if in the lower and in the upper position of the ground SHG drive the rate of pressure drop on the buffer is more than 2 MPa in 15 minutes, then make a conclusion about the leakage of the switch and / or tubing in the interval from the ESP to the wellhead, start the SHG and ESP in operation, without stopping the SHG of the upper of the object, stop the operation of the ESP of the lower object, immediately after stopping the ESP of the lower object, the liquid level in the annulus is monitored, and the pressure change under the packer is periodically recorded according to the TMS on the display of the SU controller, with a steadily increasing I conclude the liquid level of the leak, and at a constant level of liquid conclude about the integrity of the packer or a portion of the tubing from the packer to the ESP.

SUMMARY OF THE INVENTION

A method for monitoring the tightness of downhole equipment is based on detecting a hydraulic connection between the above-packer and under-packer zones by detecting changes in the liquid level, gas pressure in the annulus, as well as the pressure at the intake of the pump operating the under-packer object when one of the development facilities stops working.

The need to study wells with simultaneous and separate production of fluids should be confirmed by indirect signs of system leakage, i.e. the corresponding dynamics of changes in the operation mode of the facility: water cut of the product, physico-chemical properties of the produced fluid, bottomhole pressure.

With a significant difference between the water content of the produced fluid and the physicochemical properties of water at the facilities, the most important information for substantiating a suspicion of a leak in the system can be a significant change in the water content of the produced fluid over a short period of time, and at the same time, the density and chemical composition of the produced water.

In FIG. 1 shows the design of a well with simultaneous and separate production during joint lifting of fluids, and FIG. 2 - with a separate rise of the produced fluids.

In FIG. 1 and 2, the following designations are adopted: 1 - pipe, 2 - packer, 3 - tubing string, 4 - ESP, receiving part and PED in the casing 5, 6 - commutator, 7 - SHGN, 8 - rod string, 9 - wellhead piping 10 - buffer, 11 - pressure gauge. Above the switch 6, the tubing string is made of a large diameter 12, in which the SHGN is located 7. Above the SHGN 7, the tubing string is made of a smaller diameter 13. The layout is located in the well 14, which revealed the lower reservoir 15 and the upper reservoir 16.

Downhole equipment operates as follows.

SHGN 7 receives the drive through the column of rods 8 and selects fluids from the upper reservoir 16 through the switch 6 and through the valve system SHGN directs them to the tubing string 12 during the joint lifting of the produced fluids (see Fig. 1), and to the tubing string 13 when separately rise above SHGN 6 to the wellhead 14. ESP 4 draws fluids from the lower reservoir 15 through pipe 1 and tubing string 3 and a casing 5 under ESP 4 and feeds them through the internal volume of switch 6 to tubing string 12 above switch 6. In tubing string 3 above SHGN 7 liquids from the bottom 15 and ve hnego 16 layers or mixed together, or separately rise up to the wellhead 14. The pressure gauge 11 on the buffer 10 wellheads 9 measures the pressure in the tubing string 12 of the well 14.

The determination of the tightness of the pumping equipment is as follows.

For a differentiated approach to detecting leaks in individual sections of the layout of downhole equipment, wells with an oil well test are preliminarily tested for tightness of the tubing string, as well as the “tubing - castle switch support” system using an ESP. This allows the exclusion method to identify the tight part of the downhole equipment and the leaky part of the remaining components in the system.

The need to investigate wells with an operating pressure must be confirmed by indirect signs of leakage, i.e. the corresponding dynamics of changes in the operation mode of the facility: water cut of the product, physico-chemical properties of the produced fluid, bottomhole pressure. With a significant difference between the water content of the produced fluid and the physicochemical properties of water in the facilities, to substantiate the suspicion of a leak in the system, the most important information can be a significant change in the water content of the produced fluid over a short period of time, at the same time, the density and chemical composition of the produced water.

Before starting studies to determine the tightness of the system at operating facilities, determine the dynamic level in the annular space of the upper object, remove the SHG dynamogram to determine the operability of the downhole pumping equipment of the upper object, take the parameters of the ESP with TMS to determine the operability of the downhole pumping equipment of the lower object, select the control a sample of fluid from the flow line to the water cut (from each line, if the well with the pressure control system is 2-lift), make sure that correctness and tightness of wellhead valves.

Stop the SHGN of the upper object. Tubing of the tubing string is carried out using an ESP of the lower object by tracking the change in pressure on the buffer during operation with a closed valve. Pressure testing of the tubing string to determine leaks in the switch is performed both in the lower and in the upper position of the ground SHGN drive.

After stopping the ESP for the time of pressure testing, the tubing is convinced of the absence of leaks in the ESP check valve. To do this, follow the testimony of the installation operation on the control system: if, after stopping the ESP, the alarm signal “turbine rotation” comes out on the control system, this indicates a drainage of the liquid from the tubing, that is, leaks on the pump check valve. If there are no leaks in the check valve, further work is continued.

If the rate of increase and decrease in pressure on the well buffer at different positions of the surface drive is identical and the rate of pressure drop is within the normal range (not more than 2 MPa in 15 minutes), this indicates the tightness of the switch and tubing in the interval from the ESP to the wellhead.

If the rate of increase in pressure on the borehole buffer in the upper position of the ground SHGN drive is lower, and the rate of drop is higher than in the lower position of the SHGN, then the lip mount is not hermetically sealed in the switch support.

If in the upper position of the ground drive SHGN ESP does not develop pressure on the well buffer, but in the lower one develops, and the liquid level rises in the annulus, this indicates the cuff of the plug-in sucker rod pump out of the switch support of the switch.

If both in the lower and upper positions of the ground-based SHG drive, the rate of pressure drop does not correspond to the norm, i.e. more than 2 MPa in 15 minutes, this indicates a leak in the switch and / or tubing string in the interval from the ESP to the wellhead.

To determine the tightness of the tubing string in the interval from the ESP to the switch - the connection point of the SHGN to the switch - the inner row of the tubing string - the outer row of the tubing string disconnect the SHGN and close the linear valve of the upper object. Next, the system is crimped at 12 MPa using the ESP of the lower object by monitoring the pressure changes on the well buffer when working on the closed valve of the wellhead harness.

If the rate of pressure drop in the system is within the normal range (no more than 2 MPa in 15 minutes) and the pressure in the flow line of the SHGN is practically unchanged, then this indicates the tightness of the tubing string in the interval from the ESP to the switch - the connection point of the SHGN with the switch is internal tubing string row - the outer row of tubing string.

If the rate of pressure drop in the system is more than 2 MPa in 15 minutes, and the pressure in the flow line of the SHGN has not changed (a slight increase is possible), then this indicates a possible leakage of the connection between the SHGN and the switch and / or tubing in the interval from the ESP to the switch and / or the outer row of the tubing string.

A stable increase in pressure on the flow line of the SHGN, accompanied by a simultaneous desire to equalize the pressure on the ESP buffer and the SHGN, as well as a further cessation of the pressure drop on the buffer of the ESP and an increase in pressure in the flow line of the SHGN, indicate that the inner row of the tubing string is leaking.

Leakage in the inner row of the tubing string leads to a significant watering of well production from an oil facility. But it is not always possible to judge the leakage of the packer by increasing the water cut. In this regard, the identification and elimination of the leakage factor of the inner row of tubing will make it possible to choose a suitable approach to research on determining the tightness of the packer itself in the layout of the 2-lift ORD ESP-SHGN.

To determine the tightness of the packer, without stopping the SHGN of the upper object, stop the operation of the ESP of the lower object. Immediately after the stop of the ESP of the lower object, the fluid level in the annulus is monitored for 3-4 hours by periodically repulsing the dynamic level, and the pressure change under the packer is periodically recorded according to the TMS on the display of the SU controller. With an unclear nature, changes in the dynamic level continue the study the next day. At the end of the study, a sample of liquid for water cut is taken.

In the process of controlling the fluid level in the annulus, it can be observed that the fluid level stably rises or the fluid level does not change.

If during the process of tracking the fluid level in the annulus increases markedly, then this indicates a leak in the packer, the tubing section from the ESP to the packer (in the absence of a casing fluid flow between two reservoirs).

When equalizing the hydrostatic pressure of the liquid column above the packer with the pressure under the packer, a further decrease in the liquid level in the annulus ceases. A sign confirming the presence of leakage of the packer, the tubing section from the ESP to the packer (in the absence of fluid flow between the two productive formations) is the correspondence of the established static pressure at the ESP reception to the dynamic level in the annulus at the end of the study. To calculate the pressure under the packer, at the end of the study, the current static pressure at the ESP reception is recorded according to the TMS test, the pressure created by the liquid column corresponding to the established dynamic level in the annulus is calculated, the obtained values are correlated, taking into account the liquid column pressure in the tubing in the range from the ESP to the packer . If the fluid level does not change, this means that the packer is tight.

Concrete example

The tightness of the downhole equipment is determined in the course of the completion of fluids from the well SHGN and ESP. 2 productive formations were opened by the well at depths of 1928 m and 1917 m. The well is equipped according to the diagram in FIG. 1. SHGN works with a flow rate of 17 m ³ / day., ESP works with a flow rate of 61 m ³ / day. Determine the dynamic level in the annulus of the upper object, equal to 1186 m. Annular pressure 1.4 MPa. The SHGN dynamogram is taken, the operation parameters of the ESP with TMS are taken, a control sample of the liquid is taken from the flow line for water cut, and the wellhead is working and tight. Stop SHGN. The SHGN rocking machine is transferred to the wellhead, alternately either in the lower or the upper position (ground drive). At the same time, the tubing is pressed with the help of the ESP of the lower object with tracking pressure changes on the buffer during operation with a closed valve. They stop the ESP and monitor the indications of the operation of the unit on the control system. There is no turbine rotation alarm. Make a conclusion about the tightness of the ESP check valve.

The rate of increase and drop in pressure on the well buffer at the different positions of the pumping unit SHGN is identical, the rate of pressure drop within no more than 2 MPa in 15 minutes. Make a conclusion about the tightness of the switch and tubing in the interval from the ESP to the wellhead.

The rate of increase in pressure on the well buffer in the upper position of the rocking machine is lower, and the rate of decrease is higher than in the lower position. Make a conclusion about the leakage of the cuff fastening in the castle support of the switch.

In the upper position of the rocking machine ШГН ЭЦН does not develop pressure on the well buffer, but in the lower position it develops and the liquid level rises in the annulus. Make a conclusion about the output of the cuff fastening of the SHGN from the castle support of the switch.

Both in the lower and upper positions of the ShGN rocking machine, the rate of pressure drop on the buffer is more than 2 MPa in 15 minutes. Make a conclusion about the leakage of the switch and / or tubing in the interval from the ESP to the wellhead.

ShGN and ESP are launched into operation. Without stopping the SHGN of the upper object, stop the operation of the ESP of the lower object. Immediately after the stop of the ESP of the lower object, the fluid level in the annulus is monitored for 4 hours, and the pressure change under the packer is periodically recorded according to the TMS on the display of the SU controller. The fluid level is unchanged. Make a conclusion about the tightness of the packer or tubing from the ESP to the packer.

As a result, it is possible to determine the tightness of deep equipment.

Claims (1)

A method for determining the tightness of downhole equipment during simultaneous and separate production of liquids from a well by a rod and electric centrifugal pump, which consists in determining the dynamic level in the annulus of the upper object, taking a dynamogram of the rod deep pump, taking the parameters of the electric centrifugal pump with a telemetric system, and taking a control sample liquids from the flow line to the water cut, make sure that the wellhead valves are working and tight, stop Then, the sucker rod pump of the upper object, both in the lower and in the upper position of the ground drive of the sucker rod pump, pressurize the tubing string using the electric centrifugal pump of the lower object and monitor the pressure changes on the buffer during operation on the closed valve, stop the electric centrifugal pump and monitor the operation of the installation at the control station, in the presence of an alarm signal “turbine rotation” make a conclusion about draining the liquid from the pump compressor pipes and the leakage of the check valve of the electric centrifugal pump, at the same rate of increase and decrease in pressure on the well buffer at different positions of the ground drive of the sucker rod pump and the rate of pressure drop within no more than 2 MPa in 15 minutes, make a conclusion about the tightness of the switch and the pump string compressor pipes in the interval from the electric centrifugal pump to the wellhead, at a rate of increase in pressure on the wellbuffer in the upper position of the ground rod depth drive the lower pump and the rate of fall higher than in the lower position of the drive of the sucker rod pump, make a conclusion about the leakage of the cuff fastening in the castle support of the switch, if in the upper position of the ground drive of the sucker-rod pump does not develop pressure on the well buffer, but develops in the lower and there is a rise in the liquid level in the annulus, then they conclude that the cuff of the sucker rod pump comes out of the switch support of the switch, if in the lower so in the upper position of the ground drive of the sucker rod pump the rate of pressure drop on the buffer is more than 2 MPa in 15 minutes, then make a conclusion about the leakage of the switch and / or tubing string in the interval from the electric centrifugal pump to the wellhead, start the sucker rod pump and electric centrifugal pump in operation, without stopping the sucker rod pump of the upper object, stop the operation of the electric centrifugal pump of the lower object, immediately after stopping the electric centrifugal pump the bottom object, the fluid level in the annulus is monitored, and the pressure change under the packer is periodically recorded according to the telemetry system on the control station controller’s display, when the fluid level is steadily increasing, a conclusion is made about leaks, and at a constant fluid level, a conclusion is made about the tightness of the packer or column section tubing from an electric centrifugal pump to a packer.

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