RU2717474C2 - Piston module of device for hydraulic protection of submersible electric motor (embodiments) - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil production and can be used in devices for hydraulic protection of submersible electric centrifugal pump installations used for production of well fluid, including bitumen-containing oil, at different depths from wells of different diameters. Piston module of device for hydraulic protection of submersible electric motor includes cartridge (1), coaxially installed in it pipe (2), which form annular chamber (3) limited by upper and lower supports (4, 5). Annular chamber (3) accommodates two annular pistons (6, 7) and protective element (8) that does not have mechanical connection with pistons (6, 7). Cavity of annular chamber (3) above pistons (6, 7) is hydraulically connected to cavity inside pipe (2).

EFFECT: invention is aimed at improvement of efficiency and reliability of operation of the device for hydraulic protection of the downhole motor, and also for increase of its service life.

19 cl, 8 dwg

Description

The invention relates to the field of oil production and can be used in devices for hydraulic protection of submersible electric centrifugal pump installations used for producing well fluid, including bitumen-containing oil, at various depths from wells of various diameters.

The main functions of the device for hydraulic protection of the electric motor (hereinafter referred to as hydraulic protection) are protection of the submersible electric motor from penetration of formation fluid, equalization of pressure between the internal cavity of the electric motor and the well, compensation of leakages and thermal expansion of the oil during operation of the electric motor. Hydroprotection consists of a tread or tread and compensator. The tread also serves to transmit torque from the electric motor to the pump and to absorb axial load from the pump shaft.

At present, diaphragm type hydraulic shields are most widely used (“Well pumping units for oil production”, Ivanovsky VN et al., 2002, pp. 131-134). In such hydroprotectors, diaphragms made of elastic elastomer are used as a compensating element of the tread and compensator. However, this design has a number of significant drawbacks, the main of which are low heat resistance and heat transfer, as well as the gas permeability of the diaphragm. All this limits the application of this design.

Partially, these disadvantages are solved in a metal-bellows hydroprotection, which has high heat resistance and is not sensitive to the gas contained in the reservoir fluid. For example, a well pumping installation is known, comprising a centrifugal pump, a submersible motor and hydraulic protection, which consists of a cylindrical body, upper and lower nipples, a shaft, a guide tube surrounding the shaft, and a bellows surrounding the guide tube (according to US 8932034B2, class F04B 35/04, publ. 01/13/15). But, it should be noted that this design as well as diaphragm hydroprotection has low heat transfer and, in addition, has a low compensating ability.

All of the above problems are solved in piston type hydraulic protections. For example, a piston tread of an engine, an engine and a pumping unit using it are known. (according to the patent US 6307290, IPC H02K 5/132, F04D 13/08, publ. 23.10.01). An annular piston (one) located in the annular chamber between the housing and the tube acts as a compensating element in the tread of the electric motor, which has the ability to reciprocate within the specified annular chamber.

The disadvantage of this device is that during the operation of such a device on the inner wall of the cylindrical body that encloses the annular chamber and the outer wall of the tube, scale deposits are formed (reaction products of the walls of the annular chamber and chemically active formation fluid). As a result, such formations can significantly impede the movement of the annular piston within the corresponding portion of the annular chamber, up to the complete jamming of the piston and, accordingly, the failure of the tread. In addition, the piston is connected with the annulus through a cavity located on top of the piston, therefore, in case of loss of tightness, the formation fluid will fall into the electric motor, which will cause a short circuit and failure.

The closest technical solution is a device for hydraulic protection of a submersible electric motor of a borehole, mainly centrifugal pump, made in the form of a tread located between the electric motor and the pump, and contains a housing, a pipe mounted coaxially to the housing and the drive shaft, nipples, an annular piston installed with the possibility of reciprocating motion in an annular chamber formed by a housing and a pipe, and dividing the chamber into two sections. The plots are filled with dielectric and formation fluids. The device also comprises a separator of said fluids freely mounted in the annular chamber from the end face of the annular piston in contact with the formation fluid and facing the second nipple, with the possibility of independent movement from the piston. The separator is made in the form of a single part, consisting of two pieces of tubes placed one in the other and rigidly interconnected by a common bottom from the side of the annular piston. The piston and the separator are installed in the annular chamber with a fit with a gap to the inner surface of the housing and to the outer surface of the pipe. The space in the gap is sealed and filled with a protective medium with hydro-oleophobic properties (according to patent RU 2513546, IPC F04D 13/10, publ. 04.20.14).

The disadvantage of this device is that in this device, communication with the annulus is in two places, which reduces the reliability of the device. And also, the prototype design allows the installation of only one piston compensator, since the sequential installation of several of these compensators will require an additional channel for communication with the annulus for each of them, which will further reduce reliability.

The piston module proposed in accordance with the invention, in various design variants, is intended for use as part of a device for hydraulic protection of an electric motor. It should be noted that the proposed piston module can be used to upgrade previously known hydraulic protection devices, including as part of the aforementioned analogues, by replacing the compensation module (diaphragm, bellows, piston) with the proposed piston module. At the same time, to ensure reliable operation of the hydraulic protection, the pressure differential required for the piston shift of the proposed module does not exceed 0.5 kgf / cm ² . Also, the module can be used in hydroprotections that are under development or planned for development in the future.

The technical result achieved by using the present invention is to increase the efficiency and reliability of the device for hydraulic protection of a borehole electric motor, as well as to increase the durability of its operation.

The specified technical result is achieved in that the piston module of the device for hydraulic protection of the submersible electric motor contains a sleeve, a pipe coaxially installed in it, which form an annular chamber bounded by upper and lower supports, two annular pistons and a protective element without mechanical connection are installed in the annular chamber with pistons, the cavity of the annular chamber above the pistons is hydraulically connected to the cavity inside the pipe, and differs in that it is installed inside the cylindrical housing of the device Properties for hydraulic protection of the electric motor with the formation of a channel between the said housing and the sleeve.

In addition, the channel between the casing and the sleeve has an annular shape.

In addition, the channel between the said housing and the sleeve is made in the form of at least one groove on the sleeve.

In addition, the cavity between the annular pistons is filled with gas.

In addition, the cavity between the annular pistons is filled with a mixture of gas and dielectric oil.

In addition, in the lower part of the annular chamber an annular filter element is installed, which simultaneously performs the function of a damper.

In addition, the filter element has hydrophobic properties.

In the particular case of the execution of the piston module of the device for hydraulic protection of the electric motor installed in the protector of the specified device inside the cylindrical body between the upper and lower nipples, the tread shaft passes inside the pipe and forms together with it an annular cavity that is hydraulically connected with the cavity of the electric motor, and the cavity of the annular chamber under the protective element is hydraulically connected to the channel between the housing and the sleeve.

In addition, the channel between the housing and the sleeve is connected through a channel in the upper nipple to another compensation module.

In the particular case of the execution of the piston module of the device for hydraulic protection of the electric motor, it is installed in the tread of the specified device inside the cylindrical body between the upper and lower nipples, the tread shaft passes inside the pipe and forms an annular cavity with it, which is hydraulically connected with the electric cavity and the channel between the body and the sleeve and the cavity of the annular chamber under the protective element is hydraulically connected to the annulus.

In the particular case of the execution of the piston module of the device for hydraulic protection of the electric motor installed in the compensator of the specified device inside the cylindrical body between the head and the base, the cavity inside the pipe in the upper part is connected with the cavity of the electric motor, and in the lower part is connected with the channel between the body and the sleeve, the cavity of the annular chamber under the protective element is hydraulically connected to the annulus.

In addition, a submersible telemetry unit is connected to the base, which is connected through cables passing inside the pipe.

The technical result is also achieved by the fact that the piston module of the device for hydraulic protection of the submersible motor contains a sleeve limited by upper and lower supports, two pistons and a protective element that does not have mechanical connection with the pistons are installed in the sleeve, and differs in that the piston module is installed in the compensator the specified device between the head and the base inside the cylindrical body with the formation of a channel between the said body and the sleeve, the cavity above the pistons is hydraulically connected to the cavity of the electric motor, the cavity under the protective element is hydraulically connected to the annulus.

In addition, the channel between the casing and the sleeve has an annular shape.

In addition, the channel between the said housing and the sleeve is made in the form of at least one groove on the sleeve.

In addition, the channel between the housing and the sleeve is connected to the cavity of the electric motor.

In addition, the channel between the housing and the sleeve is connected with the annulus.

In addition, the cavity between the pistons is filled with gas.

In addition, the cavity between the pistons is filled with a mixture of gas and dielectric oil.

In addition, a filter element is installed in the lower part of the liner, which simultaneously functions as a damper.

In addition, the filter element has hydrophobic properties. The invention is illustrated by the following drawings:

FIG. 1 - piston module;

FIG. 2 is a layout diagram of a device for installing a submersible electric centrifugal pump with hydraulic protection, implemented as a tread, without using a compensator;

FIG. 3 is a layout diagram of a device for installing a submersible electric centrifugal pump with hydroprotection implemented as a tread using a compensator;

FIG. 4 - protector of hydraulic protection with a piston module with the possibility of sequential installation of another module;

FIG. 5 - tread waterproof with a piston module;

FIG. 6 - hydroprotection compensator with piston module;

FIG. 7 - hydroprotection compensator with a piston module and a submersible telemetry unit installed below;

FIG. 8 - hydroprotection compensator with piston module.

The piston module of the device for hydraulic protection of the electric motor (Fig. 1, hereinafter referred to as the piston module) comprises a sleeve 1 and a pipe 2 coaxially mounted therein. Together they form an annular chamber 3, bounded by an upper support 4 and a lower support 5. In the annular chamber 3, an upper the annular piston 6, the lower annular piston 7 and the protective element 8. Moreover, the protective element 8 does not have a mechanical connection with the lower annular piston 7, and serves to separate the reservoir fluid and dielectric oil, as well as to protect against ingress of m mechanical impurities in the area of movement of the annular pistons 6 and 7. The cavity of the annular chamber 3 above the annular pistons 6 and 7 is connected with the cavity inside the pipe 2 through the channel 9. Grooves (flats) 10 are made on the sleeve 1. A filter element 11 is installed in the lower part of the annular chamber 3 , which serves to filter the fluid entering the piston module, and also serves as a damper for the protective element 8. The filter element 11 may be made of a material having hydrophobic properties, or coated with a hydrophobic coating.

The piston module can be installed in the device for hydraulic protection of the electric motor (hereinafter referred to as hydraulic protection), which is an integral part of the installation of a submersible electric centrifugal pump.

In FIG. 2 is a diagram of the installation, consisting of an electric centrifugal pump 12 with a receiving module 13, suspended on a string of tubing 14, are located below the hydraulic protection, implemented in the form of a tread 15, and a submersible electric motor (PED) 16, which is powered by cable 17. The installation descends into the well inside the casing 18. The piston module is an integral element of the tread 15.

In FIG. 3 is a diagram of the installation, consisting of an electric centrifugal pump 12 with a receiving module 13, suspended on a string of tubing 14, are located below the hydraulic protection, implemented in the form of a tread 15 and a compensator 19. A submersible motor (PED) 16, which is powered cable 17, is located between the tread 15 and the compensator 19. The piston module is an integral element of the compensator 19 and (or) the tread 15.

One of the options for using the piston module in the tread is shown in FIG. 4. The piston module is located inside the cylindrical housing 20 between the upper nipple 21 and the lower nipple 22. Inside the pipe 2 passes and forms with it an annular cavity shaft 23 having radial bearings in the form of a bearing 24 mounted in the upper nipple 21, a bearing 25 mounted in the lower nipple 22, and the bearing 26 in the base 27. And also, an axial support in the form of a heel 28, installed between the lower nipple 22 and the base 27. An end seal 29 is installed on the shaft 23.

Between the sleeve 1 and the housing 20, a channel 30 is made, which can be annular if the outer surface of the sleeve 1 is cylindrical, or in the form of one or more grooves 11 on the sleeve 1.

The annular pistons 6 and 7 form a cavity 31 in the annular chamber 3. The cavity 31 can be partially or completely filled with gas, for example, air, inert gas, hydrocarbon gas, etc., which will increase the sensitivity of the device to changes in oil volume and increase reliability, since with small changes in volume, only the upper annular piston 6 will move.

At the base 27, a channel 32 is provided for communication with the PED cavity and pumping dielectric oil before the hydroprotection is released.

Channels 33, 34 and 35 are made in the upper nipple 21. Channel 33 serves to connect the internal cavity of the hydraulic protection with the annulus or other compensation and protection module (similar or, for example, labyrinth). The annulus means the space inside the casing 18. A valve 36 is installed in the channel 34, which serves to discharge excess oil and to drain the gas dissolved in the oil. Channel 35 is used when filling the hydraulic protection device for air outlet and after filling it is damped by the plug 37.

In the lower nipple 21, a channel 38 is made for communication with the PED cavity and pumping dielectric oil before lowering the hydraulic protection.

The cavity 39 of the annular chamber 3 under the protective element 8 is hydraulically connected by a channel 40 with a channel 30 between the housing and the sleeve.

A second use of the piston module in the tread is shown in FIG. 5. This option differs from the above in that the cavity 39 of the annular chamber 3 under the protective element 8 is hydraulically connected by the channel 41 to the annulus.

In the channel 41, a plug 42 can be installed, which protects the piston module from a sharp increase in pressure during descent, as a result of which oil can be squeezed out of the annular chamber 3. When the motor starts, the plug 42 is squeezed out due to the thermal expansion of the oil or is dissolved by the reservoir fluid, provided that it is made of appropriate material.

Also, a channel 43 is made in the lower nipple 22, which connects the annular cavity formed by the pipe 2 and the shaft 23 with the channel 30.

In the upper nipple 21, a channel 44 is made, in which a valve 35 is located, which serves to discharge excess oil and discharge gas dissolved in the oil into the annulus.

An embodiment of the use of the piston module in the compensator is shown in FIG. 6. The piston module is located inside the cylindrical body 45 between the head 46 and the base 47.

Between the sleeve 1 and the housing 45, a channel 48 is made, which can be annular if the outer surface of the sleeve 1 is cylindrical, or in the form of one or more grooves 11 on the sleeve 1.

The cavity 39 of the annular chamber 3 under the protective element 8 is hydraulically connected by a channel 49 in the base 47 with the annulus.

A plug 50 can be installed in the channel 49, which protects the piston module from a sharp increase in pressure during descent, as a result of which oil can be squeezed out of the annular chamber 3. When the motor starts to work, the plug 50 is squeezed out due to the thermal expansion of the oil or is dissolved by the reservoir fluid, provided that it is made of appropriate material.

Also, in the base 47, a channel 51 is made that connects the cavity inside the pipe 2 to the channel 48. At the head 46, a channel 52 is made that connects the channel 48 to the PED cavity. This arrangement allows the circulation of PED oil through the compensator, providing better cooling.

In FIG. 7 shows a variant with connection to the compensator of the immersion telemetry unit 53. Block 53 is bolted 54 to the base 47. The wires 55 from the PEM to the immersion telemetry unit 53 pass inside the pipe 2.

The second variant of the piston module and its installation in the hydroprotection compensator are shown in FIG. eight.

The piston module comprises a sleeve 1, an upper support 56 and a lower support 57. In the sleeve 1, an upper piston 58, a lower piston 59 and a protective element 60 are installed. Moreover, the protective element 60 is not mechanically connected with the lower piston 59, and serves to separate the formation fluid and dielectric oil, as well as to protect against ingress of mechanical impurities in the region of movement of the annular pistons 58 and 59. A filter element 61 is installed in the lower part of the sleeve 1, which serves to filter the fluid entering the piston module, and also serves as a damper for For the protective element 60. The filter element 61 may be made of a material having hydrophobic properties, or coated with a hydrophobic coating.

The pistons 58 and 59 form a cavity 62. The cavity 62 can be partially or completely filled with gas, for example, air, inert gas, hydrocarbon gas, etc., which will increase the sensitivity of the device to changes in oil volume and increase reliability, as with small changes only the upper piston 58 will move the volume.

The piston module is located inside the cylindrical housing 45 between the head 46 and the base 63.

The cavity 64 under the protective element 60 is hydraulically connected by a channel 65 in the base 63 with the annulus. The cavity 66 above the upper piston 58 is connected with the cavity of the electric motor. Channel 52 connects channel 48 to the cavity of the motor.

The piston module as part of the hydraulic motor protection device, made in the form of a tread, operates as follows.

Before descent, the hydraulic protection device is mounted with an electric motor and filled with dielectric oil. PED oil is pumped through the base 27 and channel 32, through the lower nipple 22 and channel 38, along the shaft 23 inside the pipe 2, through the channel 9 in the upper support 4 enters the annular cavity 3 above the upper annular piston 6. Air is discharged through the channel 35, and after it is completely filled, it is suppressed by plug 37.

After the descent into the well, the pumping unit is launched into operation by turning on the electric motor. The dielectric oil located in its inner cavity heats up and begins to expand gradually (its working volume increases), and, consequently, the dielectric oil pressure increases in the inner cavity of the electric motor and the cavity of the annular chamber hydraulically connected to it 3. The excess volume of oil exits through the valve 36 in the upper nipple 21. In the future, with minor changes in volume, the compensation for changes in the volume of oil resulting from leaks or temperature changes is due to the movement of the upper piston 6 (due to a change in the volume of the cavity of the annular chamber 31 due to the gas located there) or the joint movement of the annular pistons 6, 7 and the hydraulically connected protective element 8.

The principle of operation of the piston module as part of the hydraulic motor protection device, made in the form of a compensator, is similar to the principle of operation of the module as part of the tread.

The piston module made according to the invention allows it to be used for the modernization of existing hydroprotectors by replacing the used compensation modules with it.

Replacing the diaphragm module with the proposed piston module will increase the heat resistance of the device, and, consequently, the operating temperature. Also, eliminate the harmful effects of gas.

Replacing the metal bellows module with the proposed piston module will increase the compensating ability of the device.

The use of a piston module in new designs will make it possible to create a hydraulic protection device for a submersible electric motor with high operational characteristics.

Claims (19)

1. The piston module of the device for hydraulic protection of a submersible electric motor, characterized in that it contains a sleeve, a pipe coaxially installed in it, which form an annular chamber bounded by upper and lower supports, two annular pistons and a protective element without mechanical connection are installed in the annular chamber with pistons, the cavity of the annular chamber above the pistons is hydraulically connected to the cavity inside the pipe. 2. The piston module according to claim 1, characterized in that it is installed inside the cylindrical housing of the device for hydraulic protection of the electric motor with the formation of a channel between the said housing and the sleeve. 3. The piston module according to claim 2, characterized in that the piston module is installed inside the cylindrical tread housing of the device for hydraulic protection of the electric motor. 4. The piston module according to claim 1, characterized in that the channel between the casing and the sleeve has an annular shape. 5. The piston module according to claim 1, characterized in that the channel between the said housing and the sleeve is made in the form of at least one groove on the sleeve. 6. The piston module according to claim 1, characterized in that the cavity between the annular pistons is filled with gas. 7. The piston module according to claim 1, characterized in that the cavity between the annular pistons is filled with a mixture of gas and dielectric oil. 8. The piston module according to claim 1, characterized in that an annular filter element is installed in the lower part of the annular chamber, which simultaneously functions as a damper. 9. The piston module according to claim 6, characterized in that the filter element has hydrophobic properties. 10. The piston module of the device for hydraulic protection of a submersible electric motor, characterized in that it contains a sleeve, a pipe coaxially mounted in it, which form an annular chamber bounded by upper and lower supports, two annular pistons and a protective element without mechanical connection are installed in the annular chamber with pistons, the cavity of the annular chamber above the pistons is hydraulically connected to the cavity of the electric motor, and the cavity under the protective element is hydraulically connected to the annulus. 11. The piston module according to claim 10, characterized in that it is installed in the compensator of the specified device between the head and the base inside the cylindrical body with the formation of a channel between the said body and the sleeve. 12. The piston module according to claim 10, characterized in that the channel between the said housing and the sleeve has an annular shape. 13. The piston module according to claim 10, characterized in that the channel between the said housing and the sleeve is made in the form of at least one groove on the sleeve. 14. The piston module according to claim 10, characterized in that the channel between the housing and the sleeve is connected to the cavity of the electric motor. 15. The piston module according to claim 10, characterized in that the channel between the housing and the sleeve is connected with the annulus. 16. The piston module according to claim 10, characterized in that the cavity between the pistons is filled with gas. 17. The piston module according to claim 10, characterized in that the cavity between the pistons is filled with a mixture of gas and dielectric oil. 18. The piston module according to claim 10, characterized in that a filter element is installed in the lower part of the sleeve, which simultaneously performs the function of a damper. 19. The piston module according to claim 18, characterized in that the filter element has hydrophobic properties.

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