RU2601685C1 - Method of operating flooded wells and system therefor - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry and can be used in operation of water-flooded oil wells at late stage of operating oil deposit. Method comprises selecting a well based on water content and presence of underlying formation. Selected well is stopped. Tubing string is lowered into well. Packer is installed between water-flooded and underlying formations. Two screw pumps are successively lowered. Lower screw pump is lowered below water-flooded formation. Upper screw pump is lowered to upper part of tubing string. By means of lower screw pump well fluid is pumped into underlying formation from water-flooded formation. Oil in water-flooded formation is displaced into upper part due to provision of required speed of pumping borehole fluid. Oil film rising onto surface is pumped withy upper screw pump. Screw pump is operated at rated frequency of 1,500 rpm. Operation of each screw pump is controlled by separate control station with frequency converter.

EFFECT: technical result is higher efficiency of operation of oil wells with high water cut.

22 cl, 1 dwg

Description

The invention relates to the oil industry and can be used in the operation of highly watered oil wells at a late stage of operation of an oil field.

A device for oil production (patent RU No. 2290497, IPC ЕВВ 43/14, publ. 12/27/2006), including two pumps installed at different depths, is used as the lower pump, an electric centrifugal pump facing down and having a liner with a packer installed below above the roof of the formation into which water is injected, or below. Perforation of the well casing is carried out under a packer in the formation. Entrance to the upper pump and entrance to the lower pump, i.e. holes in the pipe string connecting the pumps are placed near the pumps.

A known method of operating a high-water oil well (patent RU No. 2394153, IPC ЕВВ 43/00, publ. 07/10/2010), including separate, thanks to the packer installed between the layers, pumping oil from the reservoir to the surface with preliminary gravity separation of products in the well for oil and water and injection of separated water into the receiving formation, and above the packer installed above the producing formation, a pump is placed on the pipe string, communicated with an inlet with a sub-packer space, and an outlet through radial f openings in the pipe string — with a packer space, with pipes of smaller diameter placed under the radial holes from the conditions of gravitational separation of products into oil and water, while the separated oil is lifted along the annulus and pipe string with the possibility of controlling its flow at the mouth, and water, controlling its amount, they are pumped through the annulus into the receiving reservoir due to the pressure of the liquid column in the well and the excess pressure created by the pump, and the interval of the receiving reservoir reported that a separate pipe to the wellhead measurement equipment, on the basis of evidence which control the quality of the receiving water pumped into the formation.

A known installation of an electric centrifugal pump for oil production and water injection into a formation (patent RU No. 2499133, IPC ЕВВ 43/14, published on November 20, 2013), closest in technical essence to the claimed device and adopted as a prototype, containing an electric centrifugal pump with an additional section, located below the submersible electric motor on the same shaft with it and having a channel in the housing for the outlet of the lower formation fluid into the above-packer space of the well, hydroprotection, a receiving pipe for the selection of the lower formation fluid with a packer installed between the upper and lower layers, and between the inlet pipe for the selection of liquid in the lower layer and the additional section of the pump, an inlet pipe is installed, which ends with a bore plunger and has a partition above which there is a channel for incoming stratified produced water into the receiving part of the additional section of the pump, and below the partition a channel is located in communication with the channel at the outlet of the additional section by means of a flat pipe, and the receiving branch pipe of the installation has a cylinder at the top that forms Jerome pipe friction pair and ending funnel-separator, wherein the upper edge of the funnel separator located above the channel exfoliated Incoming water into the inlet pipe.

A known method of oil production (patent RU No. 2290497, IPC ЕВВ 43/14, publ. 12/27/2006, patent holder of OAO Tatneft named after VD Shashin), the closest in technical essence to the claimed method and adopted as a prototype, including separate pumping oil from the reservoir through the borehole to the surface and water to the underlying horizon with two pumps installed at different depths, and an electric centrifugal pump, facing down and having a liner with a packer installed above the roof of the formation, is used as the bottom pump; into which water is injected, or lower, the upper pump is installed at the maximum height, the ratio of the productivity of the lower and upper pumps is selected depending on the ratio of the amount of water and oil entering the well, and the total productivity of the pumps is selected from the condition of gravity separation of the formation fluid in the well into oil and water and pumping lower oil-free water.

However, the known analogues are not effective enough when working in highly watered wells, because they do not allow individual regulation of pressure-flow characteristics (at various frequencies of rotation of the pump shaft) of water injection into the underlying reservoir and oil production.

The application of the claimed method allows the separate operation of the lower pump, giving it the necessary high productivity and pressure due to the high water cut of the well, and the upper pump with lower characteristics than the lower one, due to the small oil flow rate. That is, the shafts of these two pumps will rotate at different frequencies.

Significant differences of the claimed invention from the prototype are:

- the use of screw pumps, which allows the system to be operated at low nominal frequencies - 1500 rpm (unlike electric centrifugal pumps that operate at a nominal frequency of 2975 rpm);

- the use of two control stations with a frequency converter and individual power supply of each of the two pumps;

- the use of a tread and compensator, where the tread is designed to protect the oil-filled electric motor from penetration of formation fluid into its internal cavity, and the compensator is used to compensate for oil leakage and its thermal changes during operation of the electric motor and its stops;

- the use of a check valve prevents the backflow of fluid into the flooded reservoir when the equipment is stopped;

- the use of a perforation pipe prevents large solid particles from entering the lower screw pump when the equipment is stopped, and during its operation, it prevents erosion of the lower layer.

The problem to which the invention is directed, is to create a method for the operation of highly watered oil wells and a system for its implementation.

The technical result to which the invention is directed is to increase the efficiency of oil wells with increased water cut.

The technical result is achieved by the method of operation of high-water wells, containing stages in which:

- make the selection of the well and its stop;

- lowered into the well tubing (tubing);

- set the packer between the flooded and underlying layers;

- two pumps are lowered sequentially: the lower one is lowered below the flooded reservoir, the upper one - to the upper part of the tubing;

- using the lower pump, the borehole fluid is injected into the underlying formation from the flooded reservoir, displacing oil in the flooded reservoir into its upper part;

- pumping the oil film rising to the surface with the upper pump;

moreover, screw pumps operate at a nominal frequency of 1500 rpm,

and the operation of each pump is controlled using a separate control station with a frequency converter.

When lowering underground equipment into the well, the system elements are connected in stages from bottom to top: perforation pipe, lower tubing, check valve, lower depth sensor, packer, lower pump with receiving grid, tread, lower electric motor, compensator, middle tubing, upper electric motor, hydraulic protection with EHV head, upper pump with receiving grid, upper depth sensor or telemetry system, upper tubing.

Well selection is carried out according to the criteria: well water cut - 93-99% and the presence of the underlying formation.

To determine the water cut of the well, samples are taken, which are then subjected to laboratory analysis.

The dynamic fluid level in the flooded formation is controlled with an echo sounder, when it is reduced to a level close to the level of the upper pump lowering, oil pumping is stopped until the level at which the well can be operated is restored.

Pressure control at the pump intake is carried out using pressure sensors (the signal from each of which goes to the corresponding control station) located in the telemetry of the submersible electric motor (PEM), which controls the settings (upper and lower permissible pressure limits at the pump intake).

The pressure in the inner cavity of the tubing is controlled by a pressure gauge installed on the mouth (pipe fittings) or by a pressure sensor. A pressure sensor can be installed in conjunction with a pressure gauge. With this method, a pressure conversion is necessary taking into account the liquid column in the tubing.

Another way to control the discharge pressure, both for the upper and lower pumps, involves installing depth sensors (type UGPK) on the tubing or telemetry systems such as TMSPR - on the pump discharge.

Monitored pressure parameters set the settings for the system.

Using the obtained pressure parameters, pressure characteristics are monitored.

All monitored parameters are displayed on the controller of the control station.

Management of system elements and control of technological parameters are carried out using control stations.

The downward velocity of the borehole fluid is 0.44 l / s or 38 m ³ / day.

Conduct sampling of recoverable products with a frequency of 1 time in 3-5 days.

The technical result is also achieved by the system for implementing the method, consisting of:

- underground equipment, including:

the upper screw pump, connected to the upper depth sensor and the upper tubing at the outlet, and at the reception, with hydraulic protection, the upper electric motor and the middle tubing,

and a lower screw pump, connected to a tread, a lower electric motor, a compensator and an average tubing at the reception, and to a lower depth sensor, a non-return valve and a lower tubing at the outflow,

with a packer installed on the bottom tubing,

- and ground equipment connected to underground equipment, including at least two control stations with a frequency converter and wellhead fittings.

At the beginning of the bottom tubing, a check valve is installed, at the outlet (at the end) there is a perforation pipe.

Above the lower electric motor are installed: a compensator, above - the average tubing.

Hydroprotection is installed under the upper screw pump, and a tread is installed over the lower screw pump.

Hydroprotection contains a flange head.

An upper depth sensor is installed above the upper screw pump, and a lower depth sensor is installed below the lower screw pump.

A pressure gauge is installed at the mouth of the pipe fittings, connected with the control station.

Along with the pressure gauge, a pressure sensor connected to the control station is installed.

Screw pumps contain input modules, which are the receiving grid.

The tubing is connected to ground equipment by piping.

Each pump electric motor is capable of individual power supply from one of the control stations.

Control stations contain controllers with displays for displaying monitored parameters.

Screw pumps are designed to operate at a nominal frequency of 1500 rpm.

The lower screw pump is configured to pump well fluid at a rate of 0.44 l / s or 38 m ³ / day.

The claimed method is as follows.

Before starting work, the well is checked for compliance with the following criteria:

- water cut of the well - 93-99%, to determine which samples are taken and water cut is measured in laboratory conditions;

- the presence of the underlying reservoir, in which you can download products.

If these criteria are satisfied, the system is lowered into the well.

According to hydraulic phenomena, a film of oil accumulates in the flooded reservoir, which, under gravity, rises to the upper layers of the flooded reservoir and which is then pumped to the surface by the upper pump.

Then set the sampling frequency of the extracted products. Sampling is carried out after the start of pumping of the oil film. The frequency is set individually for each well depending on the initial sample, for example, once every 3-5 days.

Additionally, control the dynamic level of the fluid using an echo sounder. When it is reduced to a critical level of descent of the upper pump, energy is automatically turned off, oil pumping is stopped until the level is restored. Level recovery time depends on oil production.

Simultaneously with the pumping of the film to the surface, the borehole fluid is injected using the lower pump into the underlying layer from the flooded. In one embodiment, the downward velocity of the injected well fluid is 0.44 l / s or 38 m ³ / day.

During the movement of a borehole fluid with low viscosity (produced water) and at a low speed, a laminar flow regime (fluid moves in layers) is observed in the flooded formation. In this mode, there is no velocity pulsation leading to the mixing of fluid particles. Therefore, the likelihood of mixing in the flooded layer of produced water and a film of oil is negligible.

Pressure control at the pump intake is carried out using pressure sensors located in the telemetry of submersible electric motors, with data output to the control station individually for each pump. The pressure at the outlet of the upper pump is controlled by a pressure gauge and a pressure sensor that measures the pressure in the internal cavity of the tubing, or by an upper depth sensor (type UGPK). The pressure at the outlet of the lower pump is controlled by the lower depth sensor (type UGPK).

When using pressure gauges and pressure sensors (or electrocontact gauges - ECM), in addition to visual pressure monitoring on the pressure gauges, it is displayed on the displays of the control station controllers, and the indicated pressure is monitored by the control stations - the system is turned off by the sensor signal according to the settings (upper and lower permissible pressure limits )

Pressure monitoring at the pump intake is carried out in order to control the settings (upper and lower permissible pressure limits at the pump intake) using pressure sensors (whose signal is sent to the control station) located in the telemetry of submersible electric motors.

The pressure in the inner cavity of the upper tubing is controlled by a manometer installed on the mouth of the pipe fittings, or by a pressure sensor. A pressure sensor can be installed in conjunction with a pressure gauge. At the same time, pressure is recalculated taking into account the liquid column in the tubing.

With another variant of the control of the discharge pressure, both for the upper and lower pumps, they install depth sensors (type UGPK) on the tubing or telemetry systems such as TMSPR installed on the pump outlets.

Using the obtained pressure parameters, pressure characteristics are monitored. Permissible and unacceptable pressure parameters are set depending on the conditions and requirements of the injection.

The inventive system is illustrated in the drawing.

The system consists of interconnected underground and ground parts, which together include the following elements:

pump-compressor pipes (tubing), consisting of three parts: 1 - upper tubing, 1 '- middle tubing, 1 "- lower tubing;

2 - upper depth sensor;

2 '- lower depth sensor;

depth sensors are used like UGPK, instead of which a telemetry system like TMSPR can be used;

3 - pressure gauge mounted on the mouth of the pipe fittings for visual pressure control, with which a pressure sensor can be installed to supply a signal to the control system with the inverter;

4 - top screw pump for oil production;

4 '- lower screw pump for pumping fluid;

5 - hydraulic protection PM92DM with an EVN flange head, combining the functions of the compensator and tread;

6 - upper oil-filled electric motor (MED);

6 '- lower oil-filled electric motor (MED);

moreover, the size of electric motors - ХХ-117 / 4М is selected depending on the required power;

7 - compensator MKV 52 (or 51), designed to compensate for oil leaks and its thermal changes during operation of the electric motor and its stops;

8 - protector MPV 52, designed to protect the oil-filled electric motor from the penetration of formation fluid into its internal cavity;

9 - non-return valve to prevent backflow of fluid into the flooded reservoir when the equipment is stopped;

10 - a perforation pipe is designed to prevent large solid particles from entering the lower pump 4 'when the equipment is stopped, and when it is working, it prevents erosion of the lower layer;

11 and 11 '- control stations with a frequency converter (control system with inverter) for monitoring and protecting technological parameters, controlling device elements;

moreover, the SU 11 is connected to the pump 4 and the electric motor 6, and the SU 11 'to the pump 4' and the electric motor 6 ';

12 - packer (sealing element for separating two media).

The underground part of the inventive system consists of top-down interconnected elements: upper tubing 1, upper depth sensor 2, upper screw pump 4 with a receiving grid, hydraulic protection 5, upper electric motor 6, middle tubing 1 ', compensator 7, lower electric motor 6' , tread 8, lower screw pump 4 'with intake screen, packer 12, lower depth sensor 2', lower tubing 1 ", check valve 9, perforation pipe 10.

The use of screw pumps 4 and 4 'allows the operation of underground equipment at low nominal frequencies of 1500 rpm.

The upper pump 4 is used to pump the rising film of oil to the surface.

The lower pump 4 'is used to pump fluid from the flooded reservoir into the underlying reservoir.

The perforation pipe 10 is designed to prevent large solid particles from entering the lower screw pump when the equipment is stopped, and when it is working, it prevents erosion of the lower layer.

Hydroprotection 5 is used to protect the upper electric motor 6 from getting into it downhole formation fluid or oil and combines the functions of the tread 8 and the compensator 7.

Hydroprotection 5 is placed under the upper screw pump 4, and the tread 8 is above the lower screw pump 4 '.

A tread 8 is installed under the lower electric motor 6 'to protect it from penetration of the formation fluid into its internal cavity.

The compensator 7 is installed above the lower electric motor 6 'to compensate for oil leaks and its thermal changes during operation of the lower electric motor 6' and its stops.

The upper and lower screw pumps 4 and 4 'have input modules where fluid or oil flows. As input module in screw pumps 4 and 4 ', a receiving grid is used.

Screw pumps 4 and 4 'are selected depending on the productivity of the well and the pressure of the well fluid.

A perforation pipe 10 is installed after the check valve 9 to prevent large solid particles from entering the intake of the lower screw pump 4 'and to prevent erosion of the lower formation.

The tubing 1 is connected to ground equipment using piping (pipe fittings), on the mouth of which a pressure gauge and a pressure sensor 3 are installed.

The ground equipment includes two control stations 11 and 11 'for regulating the operation of each of the pumps 4 and 4'.

Each of the control systems 11 and 11 'with the inverter serves to control the speed of one of the electric motors 6 and 6', which allows you to adjust the performance of the corresponding screw pump 4 and 4 '.

The system operates as follows.

The elements of the system are connected in stages from the bottom up to the well: perforation pipe 10, lower tubing 1 ", non-return valve 9, lower depth sensor (UGPK type) 2 ', packer 12, lower pump with intake mesh 4', tread 8, lower ED 6 ', compensator 7, middle tubing 1', upper ED 6, hydroprotection 5 with an EVN head; upper pump with a receiving grid 4, upper depth sensor (UGPK type) 2 (or a telemetry system like TMSR);

- after installing the equipment in the well, the lower electric motor 6 'is started using the signal from the control system 11', and the upper electric motor 6 is launched using the signal from the control system 11;

- from electric motors 6 and 6 ', pumps 4 and 4' begin to work;

- using the lower screw pump 4 'pump the fluid from the flooded layer into the underlying (top-down) through the perforation pipe 10;

- the oil displaced to the surface is pumped out by the upper screw pump 4.

When pumping fluid from an overlying waterlogged formation with a lower pump 4 ', an oil film located in a waterlogged reservoir, under gravity, rises to the upper layers of the waterlogged reservoir, which is then pumped out by the upper pump 4 to the surface.

In this case, pressure monitoring is carried out at the reception of pumps 4 and 4 'using pressure sensors located in the telemetry of electric motors 6 and 6'.

Pressure control in the inner cavity of the tubing 1 is carried out using a manometer with a pressure sensor 3 mounted on the mouth of the pipe fittings.

Pressure control in the inner cavity of the middle tubing 1 'is not conducted, because it is used only to connect the upper electric motor 6 and the compensator 7. Pressure control in the inner cavity of the lower tubing 1 ″ is carried out using the lower depth sensor 2 ’.

Using the obtained pressure parameters, the pressure characteristics of each pump 4 and 4 'are controlled with the help of SU 11 and SU 11', respectively. Permissible and unacceptable pressure parameters are set depending on the conditions and requirements of the injection.

Hydroprotection 5 and tread 8 prevent the wellbore formation fluid from entering the internal cavity of electric motors 6 and 6 '.

The compensator 7 compensates for oil leakage and thermal changes of the lower motor 6 'during its operation and stops.

The non-return valve 9 prevents the backflow of fluid into the flooded formation in the event of a shutdown of the system.

The perforation pipe 10 is designed to prevent the ingress of large solid particles into the lower pump 4 'when the system is stopped, and during its operation it prevents erosion of the lower layer.

At the same time, the dynamic level of the liquid is additionally controlled using an echo sounder. When it is reduced to a critical level of descent of the upper pump 4, the energy is automatically turned off, oil pumping is stopped until the level is restored. Level recovery time depends on oil production.

Claims (22)

1. A method of operating high-water wells, comprising the steps of:
- make the selection of the well and its stop;
- lowered into the well tubing - tubing;
- set the packer between the flooded and underlying layers;
- two screw pumps are lowered sequentially: the lower one is lowered below the flooded layer, the upper one - to the upper part of the tubing;
- using the lower screw pump, the injection of well fluid into the underlying reservoir from the flooded reservoir;
- displace oil in the flooded reservoir in its upper part by ensuring the necessary speed of injection of well fluid;
- pumping the oil film rising to the surface with the upper screw pump,
moreover, the operation of screw pumps is provided at a nominal frequency of 1500 rpm, and the operation of each screw pump is controlled using a separate control station with a frequency converter. 2. The method according to p. 1, in which the selection of the well is carried out according to the criteria: well water cut - 93-99%, the presence of an underlying formation. 3. The method according to p. 2, in which samples are preliminarily determined to determine the water cut of the well, which are then subjected to laboratory analysis. 4. The method according to p. 1, in which the dynamic level of the fluid in the flooded formation is monitored using an echo sounder, when it is reduced to a level close to the level of the descent of the upper screw pump, oil pumping is stopped until the level at which the well can be operated is restored. 5. The method according to p. 1, in which the pressure is measured and controlled at the reception of screw pumps using pressure sensors located in the telemetry of the submersible motor with data output to the control station, and the pressure measurement and control at the output of the upper screw pump is controlled by a manometer and sensor pressure, which measure the pressure in the internal cavity of the tubing installed on the mouth of the pipe fittings, or the upper depth sensor, and at the outlet of the lower pump - the lower depth sensor. 6. The method according to p. 5, in which using the obtained pressure parameters control the pressure characteristics of the pumps. 7. The method according to claim 5, wherein the monitored pressure parameters are displayed on the display of the controller of the control station. 8. The method according to p. 1, in which the control of the elements of the system and control of technological parameters are carried out using the control station. 9. The method according to p. 1, in which the downward velocity of the injected well fluid is 0.44 l / s or 38 m ³ / day. 10. The method according to p. 1, in which they take samples of recoverable products with a frequency of 1 time every 3-5 days. 11. System for the operation of high-water wells, consisting of:
- underground equipment, including:
upper screw pump for pumping oil, connected to the upper depth sensor and upper tubing on the outflow - tubing, and at the reception - with hydraulic protection, upper electric motor and medium tubing;
a lower screw pump for injecting well fluid at a predetermined speed into the underlying formation from a flooded formation, connected to a tread, a lower electric motor, a compensator and an average tubing at the receiving end, and to a lower depth sensor, a check valve and a lower tubing, on the lower Tubing installed packer;
- ground equipment connected to underground equipment, including at least two control stations with frequency converters for regulating the operation of each screw pump, which are configured to operate at a nominal frequency of 1500 rpm, and wellhead pipe fittings. 12. The system according to claim 11, in which a check valve is attached to the intake of the lower tubing, and a perforation pipe to the discharge. 13. The system of claim 11, wherein the compensator is located above the lower electric motor. 14. The system of claim 11, wherein the hydroprotection comprises a flange head. 15. The system of claim 11, wherein an upper depth sensor is mounted above the upper screw pump, and a lower depth sensor, or telemetry system, is located below the lower screw pump. 16. The system of claim 11, wherein a pressure gauge is installed at the mouth of the pipe fitting. 17. The system according to claim 11 or 16, in which, along with the pressure gauge, a pressure sensor is connected associated with the control stations. 18. The system of claim 11, wherein the screw pumps comprise input modules, the receiving grid of which is provided. 19. The system of claim 11, wherein the tubing is connected to ground equipment by piping. 20. The system of claim 11, wherein each screw pump is configured to individually power from one of the control stations. 21. The system of claim 11, wherein the control stations comprise controllers with displays for displaying monitored parameters. 22. The system of claim 11, wherein the lower screw pump is configured to pump well fluid at a rate of 0.44 l / s or 38 m ³ / day.

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