RU60613U1 - SUBMERSIBLE BORE PUMP UNIT FOR OIL PRODUCTION, SAFETY AND RETURN VALVES OF A SUBMERSIBLE BORE PUMP UNIT, AND A DEVICE FOR SEALING A RING GAP IN A WELL - Google Patents

Abstract

Technical solutions relate to devices for filtering a water-oil mixture of oil wells and can be used in the oil and gas industry, mainly in oil production from sand-producing wells, to protect submersible pumping equipment from the effects of mechanical impurities contained in the pumped liquid, as well as to protect pumping equipment from emergency operating conditions when the filter devices are clogged and for their periodic washing. A submersible borehole pumping unit for oil production includes a submersible borehole pump, means for filtering the pumped liquid and a safety valve configured to connect to the annulus of the cavity of the pump unit located behind the means for filtering along the pumped liquid with increasing pressure in annulus above a given value. In this case, the pump unit is equipped with a check valve located downstream of the pumped liquid and designed to limit the flow of fluid flowing from the tubing string into the pump cavity when it stops. The technical result achieved is to increase the durability and reliability of the pumping unit, in particular, operated in difficult conditions, characterized by a high content of solids in the pumped

liquid, by providing the possibility of fine filtration of the pumped liquid, which is realized due to periodic cleaning of the filtering elements and reliable protection of the pump unit from abnormal operating conditions in case of clogging of the filtering elements with particles of solids. The safety valve of a submersible borehole pumping unit for oil production includes a shut-off element for closing an opening designed to connect the body cavity to the annulus. The locking element is pressed by a spring with a predetermined force to the housing element in which the aforementioned hole is made. In this case, the spring is placed in a cavity isolated from at least the main flow of the pumped liquid. The technical result achieved is to provide effective protection of the pump unit from abnormal operating conditions in the event of filter elements being clogged by particles of mechanical impurities by providing the possibility of setting the pressure of the safety valve to operate with the required accuracy throughout the life of the valve. The non-return valve of a submersible borehole pumping unit for oil production includes a seat and a shut-off element, which is made with an opening designed to ensure the flow of formation fluid from the tubing string into the pump cavity when it stops and to limit the flow of flowing fluid. Achievable technical result consists in enabling periodic cleaning of the filtering elements of the pumping unit and setting the flow rate of fluid flowing from the tubing when washing the filter, with the required accuracy without complicating the design and reducing the reliability of the check valve. A device for sealing an annular gap in a well includes a pipe to provide

movement of the fluid flow to the pump intake, as well as ring sealing elements. In this case, the device is equipped with a sleeve mounted on the pipe with the possibility of free axial movement along the specified pipe, and the sealing elements are fixed on the outer surface of the sleeve. The technical result achieved is to facilitate the descent of the device into the well.

20 s.p. f-ly, 6 ill.

Description

Technical solutions relate to devices for filtering a water-oil mixture of oil wells and can be used in the oil and gas industry, mainly in oil production from sand-producing wells, to protect submersible pumping equipment from the effects of mechanical impurities contained in the pumped liquid, as well as to protect pumping equipment from emergency operating modes when filtering devices are clogged and for their periodic washing.

Known submersible borehole pumping unit for oil production, described in patent RU 2230181 C2, 02.20.2004, which includes a submersible borehole pump, means for filtering the pumped liquid from particles of mechanical impurities and its magnetic processing, arranged before the pump is received along the pumped liquid. The pump unit contains means for ensuring the movement of the flow of the pumped liquid to the intake of the pump through the filtering means. Means for providing flow movement include a hollow cylindrical casing configured to accommodate an immersion inside it

the electric motor of the pumping unit in such a way that the flow of the pumped liquid through the gap between the casing and the electric motor is provided, means for securing the upper end of the casing above the pump inlet hole before lowering the pumping unit into the well and a hollow cylindrical shank adapted to be fixed from the lower end of the casing providing movement of the main flow of formation fluid through the lower end of the liner, on which the receiving unit of the pumping unit is made a regatta including said filter and a magnetic system.

Known submersible borehole pumping unit for oil production, described in patent US Re.35454 E, 02/18/1997 including a submersible borehole pump, means for separating the pumped liquid from particles of mechanical impurities, arranged before receiving the pump along the pumped liquid and means for providing the movement of the fluid flow to the intake of the pump through the filtering means. Means for ensuring the flow movement include a nozzle, the upper end of which is made possible to be fixed on the lower module of the pump unit before the pump unit is lowered into the well, and at the lower end of the nozzle, a receiving unit of the pump unit is made, including a separator for separating particles of mechanical impurities. Perforations are made in the middle part of the nozzle, and a cylindrical plug is mounted between the perforations and the receiving unit on the outer surface of the nozzle, which is made with the possibility of a substantially sealed installation

in the string of production (casing) pipes when placing the pump unit in the well.

A common drawback of the analogues described above is the lack of means to protect the pump from supply disruption and to protect the submersible motor from overheating when the filter (separator) is clogged by particles of mechanical impurities, as well as the lack of means for periodic cleaning of the filter (separator).

Known submersible borehole pumping unit for oil production (see certificate RU 3143 U1, 11.16.1996 or patent RU 2213849 C2, 02.27.2001 or patent RU 2161696 C2, 01.10.2001), which includes a submersible borehole pump, means for filtering the pumped liquids from solids particles, located before the pump is received in the direction of the pumped liquid, a safety valve (ball (see RU 2161696) or in the form of elastic petals formed by U-shaped slots in the valve walls - see RU 3143 U1), made with the possibility connection with annulus the cavity of the pumping unit, located behind the means for filtering in the direction of the pumped liquid, with increasing pressure in the annulus above a predetermined value (see RU 2213849 C2). The specified technical solution is taken as a prototype for the first utility model of the claimed group.

The main disadvantages of the prototype is the lack of the above tools for periodic cleaning of the filter, as well as the lack of the ability to accurately set and control the opening force of the locking element

and, accordingly, the pressure of the safety valve.

Known safety valve of a submersible borehole pumping unit for oil production, described in the aforementioned patent RU 2161696 C2, 01/10/2001, including a housing designed to be mounted on the pumping unit, so that the cavity of the housing is hydraulically connected to the cavity of the pumping unit located for means for filtering the pumped liquid in the direction of its movement, the hole connecting the body cavity with the annulus when the pump unit is placed in the well, and the shut-off element is closed the aforementioned hole.

The main disadvantages of the described analogues is the lack of the ability to accurately set and control the opening force of the locking element.

A known safety valve of a submersible borehole pumping unit for oil production, described in US Pat. No. 5,494,109 A, 02/27/1996, including a housing designed to be mounted on the pumping unit, so that the cavity of the housing is hydraulically connected to the cavity of the pumping unit located behind the means to filter the pumped liquid in the direction of its movement. An opening is made in the housing for connecting the cavity of the housing to the annulus. The valve also includes a locking member for closing said opening, wherein the locking member is pressed by a spring

with a given force to the housing element in which said hole is made, with the possibility of opening this hole with increasing pressure in the annulus above a predetermined value.

The locking member is a hollow cylindrical piston with an axial bore closed with a ball valve from the end side, with which the locking member is pressed against said housing element. Radial channels are made in the side wall of the locking member for connecting the axial hole of the locking member to the annular cavity of the housing associated with said opening for connecting the cavity of the housing to the annulus. The locking body is placed in the corresponding hole of the housing with the possibility of axial movement, and the spring is a helical coil spring and placed in the cavity formed by the axial hole of the locking body.

The specified technical solution is taken as a prototype for the second utility model of the claimed group.

The main disadvantages of the prototype are the design complexity and lack of reliability, since the spring is exposed to a hostile environment during operation of the valve, which can lead to a change in the properties of the spring as a result of its corrosion and, accordingly, a change in the valve opening force.

Known check valve submersible borehole pumping unit for oil production, described in the copyright certificate SU 898119 A1, 01/15/1982, designed to be placed behind the pump in the direction of travel

pumped liquid. The non-return valve includes a first shutoff member configured to be placed on the valve seat during fluid flow from the tubing string, and a second shutoff member pressed against the second seat with a predetermined force and designed to provide fluid flow from the tubing string during forced flushing of the pump using a flushing unit located on the surface.

The main disadvantages of this analogue is the need to use a special flushing unit to open the second shut-off element, which creates additional pressure that develops with the pressure of the liquid column in the tubing string.

Known check valve of a submersible borehole pumping unit for oil production, described in patent US 6533033 B2, 03/18/2003, including a seat designed to be placed behind the pump in the direction of the pumped liquid, as well as a shut-off element made with the possibility of placing on the valve seat during the flow of fluid from the tubing string and the flow of at least a portion of the reservoir fluid from the tubing string into the cavity of the pump assembly casing through a channel whose inlet is laid in front of the shut-off body along the flow of fluid from the tubing string. The specified technical solution is taken as a prototype for the third utility model of the claimed group.

The main disadvantages of the prototype is the complexity of the design,

insufficient reliability and durability of the locking element subjected to elastic deformations during operation, high hydraulic resistance created by the check valve of the design described in the patent when the pumped fluid moves from the pump to the tubing, which will reduce the overall efficiency of the installation.

A device is known for sealing an annular gap in a well (see patent RU 37146 U1, 04/10/2004), which includes a pipe made with the possibility of connecting with threaded couplings to the corresponding elements of the pipe, designed to ensure the flow of the pumped liquid to the intake of the submersible pump the pump unit through means for filtering the flow, and at least two annular sealing elements of elastic material, in particular rubber, fixed to the outer surface of the pipe with ring spacers. The device prevents the backflow of fluid from the part of the annulus into which the receiving holes with the filter exit into the lower part of the annulus. The specified technical solution is taken as a prototype for the fourth utility model of the claimed group.

The main disadvantages of the prototype is the difficulty of lowering the device into the well with a significant amount of deposits on the walls of the casing, a well having curved sections, etc., where there is a high probability of jamming of the device and damage to the sealing elements.

Thus, the task to which the claimed group of utility models is directed is to create a pumping unit with a device for filtering formation fluid, providing the possibility of oil production from sand-producing wells, protecting the pumping unit from abnormal operating conditions when the filtering devices are dirty, and the possibility of periodic flushing.

The technical result achieved by implementing the first technical solution from the claimed group of utility models is to increase the durability and reliability of the pump unit, in particular, operated in difficult conditions, characterized by a high content of mechanical impurities in the pumped liquid, by allowing fine filtration of the pumped liquid sold due to periodic cleaning of filter elements and reliable protection of the pump unit from abnormal operating conditions case of clogging of the filter elements by particles of mechanical impurities.

The technical result achieved during the implementation of the second technical solution from the claimed group of utility models is to provide effective protection of the pump unit from abnormal operating conditions in case of clogging of the filter elements by particles of mechanical impurities by providing the ability to set the pressure of the safety valve to operate with the required accuracy over the entire life cycle Kapana.

The technical result achieved by the implementation of the third technical

The solution from the claimed group of utility models consists in providing the possibility of periodic cleaning of the filtering elements of the pumping unit and setting the flow rate of the fluid flowing from the tubing when washing the filter, with the required accuracy without complicating the design and reducing the reliability of the check valve.

The technical result achieved by the implementation of the fourth technical solution from the claimed group of utility models is to facilitate the descent of the device into the well.

A submersible borehole pumping unit for oil production, which ensures the achievement of the above technical result, includes a submersible borehole pump, means for filtering the pumped liquid from at least particles of mechanical impurities located before the pump is received along the pumped liquid, a safety valve made with the possibility of connection with the annular space of the cavity of the pumping unit, located behind the means for filtering along the pumped liquid, pr increasing the pressure in the annulus above a predetermined value. Moreover, unlike the prototype, the pump unit is equipped with a check valve located behind the pump in the direction of the pumped liquid and designed to limit the flow of fluid flowing from the tubing string into the pump cavity when it stops.

In addition, in the particular case of the implementation of the first utility model of the claimed group, the pump unit contains means for providing movement

the flow of the pumped liquid to the pump intake through the filtering means, the means for ensuring the flow movement include a nozzle, the upper end of which is configured to be fixed on the lower module of the pumping unit before lowering the pumping unit into the well, and the receiving unit of the pumping unit is made at the second end of the pipe comprising at least one filter and a safety valve, perforations are made in the middle part of the nozzle, and a device is fixed between the perforations and the receiving unit for sealing an annular gap configured to substantially leak tight in the production string when placed downhole pump assembly and forming part of the nozzle.

In addition, in the particular case of the implementation of the first utility model from the claimed group, a safety valve is located on the lower end of the pipe

In addition, in the particular case of the first utility model from the claimed group, the pipe consists of pipes interconnected by couplings.

In addition, in the particular case of the implementation of the first utility model from the claimed group, the upper pipe of the nozzle is made with the possibility of connection with the flange of the lower module of the pumping unit using a coupling.

In addition, in the particular case of the implementation of the first utility model of the claimed group, the pump unit contains means for ensuring the movement of the flow of the pumped liquid to the pump through means

Filtration means for ensuring the movement of the flow include a hollow cylindrical casing configured to accommodate the submersible motor of the pump unit inside it so that the flow of the pumped liquid through the gap between the casing and the motor is provided, means for essentially tightly securing the upper the end of the casing above the inlet of the pump before lowering the pump unit into the well and a hollow cylindrical shank, made with the possibility Strongly fastening from the lower open end of the housing to ensure formation fluid flow through the lower end of the shank, on which is formed a receiving node pump unit comprising at least one filter, and a safety valve.

In addition, in the particular case of the implementation of the first utility model of the claimed group, a safety valve is located on the lower end of the shank.

In addition, in the particular case of the implementation of the first utility model of the claimed group, the means for filtering the pumped liquid include at least one slotted filter including two annular bandages fixed on both sides of the receiving holes of the pipe designed to allow movement the flow of the pumped liquid to the intake of the pump through the means for filtering the flow, and the ends of the wire winding of the filter are fixed in bandages.

In addition, in the particular case of the implementation of the first utility model of the declared

groups, means for filtering the pumped liquid include at least one filter consisting of two concentrically arranged cylindrical wire screens fixed at the level of the receiving holes of the pipe, designed to ensure the flow of the pumped liquid to the pump through the means for filtering the flow and gravel particles are placed between the mesh screens.

The safety valve of a submersible borehole pumping unit for oil production, ensuring the achievement of the above technical result, includes a casing designed to be mounted on the pumping unit, so that the cavity of the casing is hydraulically connected to the cavity of the pumping unit located behind the means for filtering the pumped liquid by the course of her movement. An opening is made in the housing for connecting the cavity of the housing to the annulus. The valve also includes a locking member for closing said opening, wherein the locking member is pressed with a predetermined force to the housing element in which said opening is made with a spring, with the possibility of opening this opening with increasing pressure in the annulus above a predetermined value. In this case, unlike the prototype, the spring is placed in a cavity isolated from at least the main flow of the pumped liquid.

In addition, in the particular case of the implementation of the second utility model from the claimed group, the locking element is a hollow cylindrical

a piston with an axial hole closed from the end side, with which the locking member is pressed against the said body element, and at least one radially oriented channel is made in the side wall of the locking member for connecting the axial hole of the locking member to the body cavity in which the said hole is made for connecting the cavity of the housing with the annulus, while the locking body is placed in the corresponding hole of the housing with the possibility of axial movement, and the spring is a helical cylinder eskuyu spring and placed in the annular cavity between the outer wall of the valve plug and the inner wall of said housing opening.

In addition, in the particular case of the implementation of the second utility model of the claimed group, a mesh is fixed on the housing for separating coarse particles of mechanical impurities when the pumped fluid moves through an opening designed to connect the housing cavity with the annulus.

In addition, in the particular case of the second utility model from the claimed group, the safety valve is equipped with means for regulating the compression force of the spring.

In addition, in the particular case of the implementation of the second utility model of the claimed group, the safety valve is equipped with an adjustment element placed in the cavity of the valve by means of a threaded connection with the possibility of axial movement, with the spring resting on one end on the adjustment element.

In addition, in the particular case of the implementation of the second utility model from the claimed group, the casing is made with the possibility of fixing on the lower end of the pipe, designed to ensure the movement of the flow of the pumped fluid to the intake of the pump through the means for filtering the flow.

The non-return valve of a submersible borehole pumping unit for oil production, ensuring the achievement of the above technical result, includes a seat designed to be placed behind the pump in the direction of the pumped liquid, as well as a shut-off element made with the possibility of placement on the valve seat when fluid flow from tubing strings and providing at least a portion of the formation fluid from the tubing string. Moreover, in contrast to the prototype, the shut-off element is made with at least one hole of a given diameter, designed to ensure the flow of formation fluid from the tubing string into the pump cavity when it stops and to limit the flow of flowing fluid.

In addition, in the particular case of the implementation of the third utility model of the claimed group, the non-return valve seat is placed in a hollow cylindrical body, at the ends of which there is a thread for connecting the body to the corresponding tubing and to the upper section or pump head of the submersible pump unit

In addition, in the particular case of the implementation of the third utility model of the declared

of the group, in the opening of the shut-off element there is a saddle of the second check valve and a shut-off element of the second check valve, made with the possibility of placement on the said saddle when the pumped liquid moves from the pump cavity into the tubing string and overlaps the shut-off hole.

In addition, in the particular case of the implementation of the third utility model from the claimed group, the check valve is equipped with a sludge trap, which is a slurry pipe fixed to the check valve seat along the pumped liquid with the possibility of placing tubing inside the column, so that the annular the gap between the outer wall of the slurry pipe and the inner wall of the corresponding pipe of the tubing string is closed on the side of the end of the sludge facing the valve seat sow pipe with the formation of an annular chamber, which is in communication with the internal cavity of the slurry pipe through through holes made in the side wall of the slurry pipe, while the slurry pipe is closed from the opposite end of the saddle.

A device for sealing an annular gap in a well, ensuring the achievement of the above technical result, includes a pipe made with the possibility of connecting with its ends to the corresponding elements of the downhole devices designed to ensure the flow of the pumped fluid to the pump intake of the submersible pump unit through flow filtration means , as well as,

at least two annular sealing elements. Moreover, unlike the prototype, the device is equipped with a sleeve mounted on the pipe with the possibility of free axial movement along the specified pipe, while the sealing elements are fixed on the outer surface of the sleeve.

In addition, in the particular case of the implementation of the fourth utility model of the claimed group, the pipe forms part of the pipe, designed to ensure the flow of the pumped fluid to the pump through the means for filtering the flow, at the top, relative to the location of the pump unit in the well, the end of the sleeve is fixed a washer with the possibility of abutment in the lower end surface of the coupling, designed to connect the pipe to the corresponding element of the pipe of the submersible pump unit, and installed in the lower part of the pipe claimed snap ring for restricting axial movement of the sleeve.

In addition, in the particular case of the implementation of the fourth utility model from the claimed group, two annular centralizers with a sphere-shaped outer surface are installed on the sleeve, between which sealing elements and annular spacers are placed alternating with each other, the upper centralizer is mounted with the possibility of abutment in the corresponding surface of the washer, and a thread is made on the lower end of the sleeve on its outer surface and a nut is installed with the possibility of pressing the lower centralizer to the elements located between the centralizers , For adjusting the degree of initial deformation of the sealing elements.

In addition, in the particular case of the implementation of the fourth utility model from the claimed group, the height of the spacers located between the elastic elements, measured in the axial direction, is in the range from 0.25 to 0.75 of their diameter.

In addition, in the particular case of the implementation of the fourth utility model of the claimed group, the outer diameter of the sealing elements is larger than the outer diameter of the spacers and smaller than the largest diameter of the centralizers, while the sealing elements are made of an elastic material capable of swelling in the formation fluid environment.

Providing the submersible pump unit with a safety and non-return valve of the claimed design allows the normal functioning of the pump unit under difficult conditions, characterized by a high content of solids in the pumped liquid, since on the one hand it protects the pump from a supply failure and the submersible motor from overheating when particles are clogged by filter elements mechanical impurities, and on the other hand allows periodic washing of filters without using special nogo equipment. All this allows the use of filter elements with a minimum cell size and, accordingly, to separate small particles from the flow, which ensures the maximum degree of purification of the pumped liquid and significantly increases the reliability and durability of the pump unit.

The implementation of the safety valve with a locking element pressed against the valve seat with a standard coil spring

compression-tension with known characteristics provides the ability to accurately set and, if necessary, control the opening force of the shut-off element and, accordingly, the response pressure of the safety valve. This provides effective protection of the pump from supply disruption and protection of the submersible motor from overheating in case of clogging of the filter elements by particles of mechanical impurities. Protection of the valve spring from the effects of the hostile environment of the formation fluid allows the elastic characteristics of the spring to remain constant throughout the life of the valve.

The holes for the overflow of part of the reservoir fluid from the tubing string directly to the check valve shut-off element avoids the appreciable complication of the check valve design. Limiting the flow of flowing fluid allows you to save part of the back pressure of the liquid column in the tubing string to facilitate starting the pump. Moreover, the claimed design of the check valve allows you to simplify the task of accurately setting the flow rate of fluid flowing from the tubing when flushing the filter, which is achieved by selecting the appropriate diameter of the hole.

Fixing the sealing elements on the sleeve mounted on the pipe of the device for sealing the annular gap with the possibility of free axial movement greatly facilitates the descent of the device into the well. The diameter of the sealing elements is almost equal to the inner diameter of the production string, so when passing through the device

sections of the well, on which the walls of the casing are contaminated with various deposits (for example, paraffin), which narrows the passage diameter of the string, or when passing a curved section of the well, etc. there is a high probability of jamming of the device, which will significantly complicate the procedure for lowering the pump unit and can lead to damage to the sealing elements. However, due to the possibility of axial movement of the pump unit relative to the sleeve on which the sealing elements are fixed, in case of jamming of the device, the tubing string with the pump unit will continue to move downward, and when the upper end of the device pipe rigidly connected to the pump unit rests against the upper end of the sleeve, further movement it will become impossible and the bushing will be impacted, which due to the significant mass of the pumping unit and tubing string will be very significant and will ensure sales Saving the device through the problem area of the well. If necessary, the impact can be carried out several times until the device is completely pushed through.

The possibility of implementing each of the technical solutions forming a group of utility models, characterized by the above set of features, is confirmed by the description of a submersible borehole pumping unit for oil production, made in accordance with the claimed group of utility models.

The description is accompanied by graphic materials, which depict the following.

Figure 1 - shows a submersible borehole pumping unit for oil production (first scheme for supplying fluid to the pump intake).

Figure 2 - shows a submersible borehole pumping unit for oil production (second fluid supply circuit to receive the pump).

Figure 3 - shows a device for sealing an annular gap in the well.

Figure 4 - shows the safety valve.

Figure 5 - shows a first embodiment of a check valve.

Figure 6 - shows a second embodiment of a check valve.

The submersible borehole pumping unit 1 for oil production includes a submersible borehole pump 2 with an input module 3, a submersible motor 4 with hydroprotection and a filter system 5, located before the pump is received in the direction of the pumped liquid. The pump unit 1 also includes a safety valve 6 for connecting the cavity of the pump unit located behind the filters 5 with the annulus when the filters are clogged. In addition, the pump unit is equipped with a check valve 7 with a hole 8, designed to clean the filters when the pump 2 is stopped due to the overflow of part of the pumped liquid from the tubing string.

The fluid supply through the filters to the pump intake can be arranged in two ways.

In accordance with the first scheme (see Figure 1), the pump unit is equipped with a pipe 9, which consists of several tubular elements connected

interconnected by threaded couplings 12. The pipe consists of an adapter 47, an inner pipe 14 of the device 11 for sealing the annular gap, made with the possibility of essentially tight installation in the production (casing) string when placing the pump unit in the well, and filters 5 mounted one above the other under device 11.

Before the pump unit is lowered into the well, the adapter 47 is mounted on the lower flange of the electric motor (hydroprotection compensator, immersion telemetry unit, etc.) using a flange coupling 13. At the lower end of the pipe, a receiving unit of the pump unit is made, which includes the mentioned filters 5 and a safety a valve 6 located on the lower end of the pipe 9. In the adapter 47, holes 10 are made through which the reservoir fluid passing through the filters 5 enters the cavity above the device 11 and enters the pump 2.

The device 11 includes a pipe 14, configured to be connected to the corresponding elements of the pipe 9 by means of couplings 12, and a sleeve 18 mounted on the pipe 14 with the possibility of free axial movement along the specified pipe. A washer 19 is welded at the upper end of the sleeve 18 with a possibility of abutment in the lower end surface of the coupling 12, and a snap ring 26 is installed in the lower part of the pipe to limit the axial movement of the sleeve 18. Two ring centralizers 30 and 40 with a sphere-shaped outer surface are installed on the sleeve, between which placed sealing elements (cuffs) 41 and metal ring spacers 42, alternating between themselves.

The height of the spacers 42 located between the elastic elements 41, measured in the axial direction, is approximately 0.5 of their diameter, and the outer diameter of the sealing elements is larger than the outer diameter of the spacers. Thus, after placing the device 11 in the production casing, annular cavities are formed between the elastic elements, which will gradually be filled with the pumped liquid and the settling particles of mechanical impurities, which will minimize the leakage of the pumped liquid through the device 11.

The upper centralizer is installed with the possibility of abutment in the corresponding surface of the washer 19, and a thread is made on the lower end of the sleeve on its outer surface, and a nut 43 is mounted, fixed with a lock nut 44, intended to compress the lower centralizer to the elements located between the centralizers to control the degree of initial deformation of the sealing elements 41, which are made of an elastic material capable of swelling in the environment of the reservoir fluid. The outer diameter of the sealing elements 41 is less than the largest diameter of the centralizers 30 and 40, which eliminates the possibility of damage to the sealing elements during the descent of the pump unit. In addition, the lower centralizer 40 during the passage of complex sections of the well act on the walls of the casing, forming the cross section necessary for the normal passage of the sealing elements 41.

while the sealing elements are made of elastic material, prone to swelling when immersed in the reservoir fluid, which along

with the above-described siltation of the annular cavities between the elements 41 provides the necessary degree of sealing of the annular gap.

The device 11 prevents the backflow of fluid from the part of the annulus into which the nozzle openings 10 exit to the lower part of the annulus from which the reservoir fluid flows into the filters 5. Due to the fact that the liquid level above the device 11 is minimal, the pressure on the plug is lower excluded due to the presence of a safety valve 6, and a slight flow of fluid through the gap between the sealing elements 41 and the wall of the production string 15 does not affect the operation of the pump unit, does not require I use other means to ensure the tightness of the device after the descent of the pump unit into the well.

In case of jamming of the device 11, the pump unit will continue to move downward due to the displacement of the pipe 14 relative to the sleeve 18 and will have an impact on the sleeve 18 when the lower end of the coupling 12 abuts the washer 19, forcing the device 11 to be forced through the problem section of the well as described above.

In accordance with the second scheme (see Figure 2), the fluid supply to the pump inlet is provided to the pump unit with a hollow cylindrical casing 16. Before lowering the pump unit into the well, the upper end of the casing is fixed above the receiving openings of the input module 3 of pump 2. The design of the casing and means for it fastening may include sealing the hole for the passage of the extension cable, but since small fluid flow

does not affect the operation of the pump unit; sealing of this hole is optional. A submersible motor 4 with hydroprotection is placed inside the casing 16 so that between the casing and the electric motor a gap is formed sufficient to ensure the normal flow of the pumped liquid. The fluid flow washes the wall of the motor housing, providing its cooling, and then enters the input module 3. For optimal use of the annular volume of wells with a small inner diameter of the production casing, the casing can be fixed with an offset relative to the longitudinal axis of the pump unit in the direction of the motor current input unit (see Patent RU 43320 U1, 2005.01.10).

From the lower open end of the casing 16, a hollow cylindrical shank 17, which is a tubing connected to each other, is fixed by means of a sleeve. Thus, after the pump assembly has been lowered into the well, the flow of formation fluid from the well perforation interval due to the depression created by the pump assembly will move towards the lower end of the liner, on which the receiving assembly of the pump assembly is made, while in the area between the perforation interval and the lower end natural gas separation will occur in the casing, and the well will act as a natural gas separator. In addition, the use of the second fluid supply circuit allows the pump unit to be lowered below the perforation zone in the casing, while due to the increased depth of the pump lowering pressure

pump intake is increased, which allows to stabilize the centrifugal pump.

The receiving unit, as well as with the first fluid supply circuit to the pump intake, includes two or more filters 5 located one above the other and a safety valve 6 located on the lower end of the shank 17.

Each of the filters 5 is a slit filter, which includes two annular bandages fixed on both sides of the receiving holes of the pipe 9 or liner 17 depending on the fluid supply circuit to the pump intake, and the ends of the filter wire are fixed in the bandages. A gravel-filled filter can also be used, which includes two concentrically arranged cylindrical wire screens fixed at the level of the inlet openings of the nozzle or liner depending on the fluid supply circuit to the pump intake, and gravel-filled particles are placed between the mesh screens.

The safety valve 6 includes a housing 20, mounted in the lower part of the pump unit at the end of the pipe 9 (liner 17) and a cover 21, forming a valve cavity, which is hydraulically connected to the cavity of the pipe (liner), located behind the means for filtering the pumped liquid along the way her movements. Inside the housing 20 is placed a locking member 22 and a hole 24 is made connecting the cavity of the housing with the annulus.

The locking body 22 is pressed against the inner wall of the housing by means of a coil spring 25 with a predetermined force determined by the characteristics of the spring, which ensures opening of the hole 24 when the pressure in the annulus increases above a predetermined value due to clogging of the filters 5 and a decrease in their throughput.

The locking element 22 is a hollow cylindrical piston placed in the corresponding hole of the housing 20 with the possibility of axial movement. The central axial hole 27 of the locking member is closed on the end side, by which the locking member is pressed against the said housing element, and four radial channels 28 are made in the side wall, connecting the central hole 27 with the cavity 29 of the housing in which the opening 24 is made. The spring 25 is placed in the annular cavity 45 between the outer wall of the locking member 22 and the inner wall of the opening 20 of the housing. In this case, the spring rests on the washer 46, which provides the required degree of isolation of the cavity 45 and the protection of the spring under the influence of an aggressive environment.

When the pressure in the annulus increases above a predetermined value, the spring 25 is compressed under the action of the force from the lower end of the shut-off member 22, which rises from the saddle and the formation fluid through the openings 24, 28 and 27 enters the pipe 9 (shank 17) bypassing the filters 5.

A mesh 23 is fixed to the housing 20 to separate coarse particles

solids when moving the pumped liquid through the hole 24.

The safety valve can be equipped with an adjusting element (not shown in the drawings) placed in the cavity of the valve by means of a threaded connection with the possibility of axial movement, in this case, the spring 25 must rest on its adjusting element with its end opposite to the locking element, which allows to regulate the compression force of the spring and, accordingly, the pressure at which the valve opens, determined by the height of the calculated dynamic fluid level in the well and the depth of descent of the pump unit and (operation unit below the perforated interval). The compression force of the spring can also be adjusted by changing the position of the cover 21 relative to the housing 20 on the thread 31.

The non-return valve 7 includes a seat 32 and a poppet type shut-off element 33 located in the flow part of the pumping unit behind the pump in the direction of the pumped liquid in a separate housing 39, the ends of which are threaded to connect the housing to the corresponding tubing and upper section (head) of the pump (not shown in the drawings).

The locking element 33 is arranged to accommodate on the valve seat 32 and block the passage of the valve channel when fluid flows from the tubing string after the pump stops. The contact surface of the seat and the locking element is sealed with

washers 34. A pipe 35 is made in the upper part of the shut-off element, which is axially displaceable in the corresponding hole of the stopper 36 fixed in the check valve body 39.

After starting the pump, the shut-off member 33 moves upward under the action of the flow of the pumped liquid, opening the channel for the passage of fluid, while the valve 7 creates minimal hydraulic resistance of the pumped liquid. After the pump stops, the liquid from the tubing string rushes down under the action of gravity, as a result of which the shut-off element sits on the seat 32.

An axial channel 8 of a given diameter is made in the locking element of the trap, connecting the cavities above and below the valve. Channel 8 is designed to ensure the flow of part of the reservoir fluid from the tubing string into the pump cavity when it is stopped. From the pump cavity, the liquid enters the pipe 9 (liner 17) and through the filters 5 enters the annulus. The overflow of liquid provides a natural flushing of the filters when the pump stops without the use of special flushing equipment and any special actions on the part of the operator. The estimated flow rate of the fluid flowing from the tubing during the washing of the filter is ensured by selecting the appropriate diameter of the hole 8. The limitation of the flow of fluid flowing allows you to save part of the back pressure of the fluid column in the tubing string, which facilitates the start-up of the pump.

In the hole 8 of the shut-off element, a seat 37 and a shut-off element 38 of the second check valve can be placed (see FIG. 6). The locking element 38 sits on the seat 37 when the pumped fluid moves from the pump cavity into the tubing string and closes the hole 8, which protects the hole from the effects of the pumped fluid flow.

The non-return valve may be equipped with a sludge trapping device, which is a sludge pipe (not shown in the drawings) closed on the upper end side thereof, which is fixed in the housing 39 above the seat 32 so that the outlet of the valve 7 is hydraulically connected to the cavity of the sludge pipe. The upper part of the slurry pipe is placed inside the corresponding pipe of the tubing string. The annular gap between the outer wall of the slurry pipe and the inner wall of the specified pipe string tubing, closed on the side of the lower end of the slurry pipe, forms an annular chamber for particulate matter settling when the pump stops. This chamber is in communication with the internal cavity of the slurry pipe by means of through holes made in the side wall of the slurry pipe, through which the flow of pumped liquid passes while the pump is running, simultaneously washing away the sediment from the formed slurry pipe of the chamber.

Claims (24)

1. Submersible borehole pumping unit for oil production, including a submersible borehole pump, means for filtering the pumped liquid, at least from particles of mechanical impurities, located in front of the pump intake along the pumped liquid, a safety valve made with the possibility of connection with the annular the space of the cavity of the pumping unit, located behind the means for filtering along the pumped fluid, with increasing pressure in the annulus above a predetermined value cheniya, characterized in that the check valve is provided located behind the pump during the movement of the pumped fluid and intended to limit the fluid flow, flowing from the column of tubing into the pump chamber when it is stopped. 2. The pump unit, according to claim 1, characterized in that it contains means for ensuring the flow of the pumped liquid to the pump intake through the filtering means, the means for ensuring the flow of flow include a pipe, the upper end of which is made with the possibility of fixing on the lower module of the pumping unit before the pumping unit is lowered into the well, and at the second end of the nozzle there is a receiving unit of the pumping unit, which includes at least one filter and a safety valve in the middle part of the pat ubka perforations, and the perforations between the node and the receiving device secured to seal the annular gap configured to substantially leak tight in the production string when placed downhole pump assembly and forming part of the nozzle. 3. The pump unit according to claim 2, characterized in that the safety valve is located on the lower end of the pipe. 4. The pump unit according to claim 2, characterized in that the nozzle consists of pipes interconnected by couplings. 5. The pump unit according to claim 4, characterized in that the upper pipe of the pipe is made with the possibility of connection with the flange of the lower module of the pumping unit using a coupling. 6. The pump unit according to claim 1, characterized in that it contains means for ensuring the flow of the pumped liquid to the pump intake through the filtering means, the means for ensuring the flow of flow include a hollow cylindrical casing configured to accommodate a pump submersible motor inside it unit in such a way that the flow of the pumped liquid through the gap between the casing and the electric motor is provided, means for essentially tight sealing the upper end of the casing above the pump inlet hole before the pump unit is lowered into the well and a hollow cylindrical shank configured to be secured from the lower open end of the casing to allow the flow of formation fluid through the lower end of the shank on which the receiving unit of the pump unit is made, including at least one filter and a safety valve. 7. The pump unit according to claim 6, characterized in that the safety valve is located on the lower end of the shank. 8. The pump unit according to claim 1, characterized in that the means for filtering the pumped liquid include at least one slit filter, including two annular bandages, fixed on both sides of the receiving holes of the pipe, designed to provide movement the flow of the pumped liquid to the intake of the pump through the means for filtering the flow, and the ends of the wire winding of the filter are fixed in bandages. 9. The pump unit according to claim 1, characterized in that the means for filtering the pumped liquid include at least one filter consisting of two concentrically arranged cylindrical wire screens fixed at the level of the receiving holes of the pipe designed to allow movement the flow of the pumped liquid to the pump through the means for filtering the flow, and gravel particles are placed between the mesh screens. 10. The safety valve of a submersible borehole pumping unit for oil production, including a housing designed to be mounted on the pumping unit, so that the cavity of the housing is hydraulically connected to the cavity of the pumping unit located behind the means for filtering the pumped liquid in the direction of its movement, in the housing has a hole designed to connect the cavity of the housing with the annulus, the valve also includes a locking member to close the specified hole, while the spring body is pressed with a predetermined force against the housing element in which the aforementioned hole is made, with the possibility of opening this hole with increasing pressure in the annulus above a predetermined value, characterized in that the spring is placed in a cavity isolated from at least the main fluid flow. 11. The safety valve according to claim 10, characterized in that the locking member is a hollow cylindrical piston with an axial hole closed at the end side, by which the locking member is pressed against said housing element, and at least one is made in the side wall of the locking member one radially oriented channel for connecting the axial hole of the locking member with the cavity of the housing, in which the aforementioned hole is made for connecting the cavity of the housing with the annulus, while the locking member is placed respectively the existing opening of the housing with the possibility of axial movement, and the spring is a helical coil spring and is placed in the annular cavity between the outer wall of the locking member and the inner wall of the specified opening of the housing. 12. The safety valve according to claim 10, characterized in that a mesh is fixed to the housing for separating coarse particles of mechanical impurities when the pumped fluid moves through an opening designed to connect the housing cavity to the annulus. 13. The safety valve of claim 10, characterized in that it is equipped with means for regulating the compression force of the spring. 14. The safety valve according to item 13, characterized in that it is equipped with an adjusting element placed in the cavity of the valve by means of a threaded connection with the possibility of axial movement, while the spring rests at one end on the adjusting element. 15. The safety valve according to claim 10, characterized in that the casing is made with the possibility of fixing on the lower end of the pipe, designed to ensure the flow of the pumped liquid to the pump through the means for filtering the flow. 16. The check valve of a submersible borehole pumping unit for oil production, including a seat designed to be placed behind the pump in the direction of the pumped liquid, as well as a shut-off element made with the possibility of placement on the valve seat when there is a fluid overflow from the tubing string and ensuring the flow of at least part of the reservoir fluid from the tubing string, characterized in that the shut-off member is made with at least one hole of a predetermined diameter a meter designed to ensure the flow of formation fluid from the tubing string into the pump cavity when it stops and to limit the flow of flowing fluid. 17. The non-return valve according to claim 16, characterized in that the non-return valve seat is housed in a hollow cylindrical body, at the ends of which a thread is made to connect the body to the corresponding tubing and to the upper section or pump head of the submersible pump unit. 18. The non-return valve according to claim 16, characterized in that a seat of the second non-return valve and a shut-off element of a second non-return valve are arranged in the opening of the shut-off member, arranged to be located on said saddle when the pumped fluid moves from the pump cavity into the tubing string and overlapping the hole of the locking element. 19. The check valve according to clause 16, characterized in that it is equipped with a sludge trapping device, which is a slurry pipe fixed to the seat of the check valve along the pumped liquid with the possibility of placing tubing inside the column, so that the annular gap between the outer the wall of the slurry pipe and the inner wall of the corresponding pipe of the tubing string is closed from the side of the end of the slurry pipe facing the valve seat to form an annular chamber, which a sludge with an internal cavity of the slurry pipe by means of through holes made in the side wall of the slurry pipe, while the slurry pipe is closed from the end opposite the saddle. 20. A device for sealing an annular gap in a well, including a pipe made with the possibility of connecting with its ends to the corresponding elements of the downhole devices designed to ensure the flow of the pumped liquid to the pump intake of the submersible pump unit through the means for filtering the flow, and also at least two annular sealing elements, characterized in that it is provided with a sleeve mounted on the pipe with the possibility of free axial movement along the specified pipe, while the sealing elements are fixed on the outer surface of the sleeve. 21. The device according to claim 20, characterized in that the pipe forms part of a nozzle designed to ensure the flow of the pumped fluid to the pump through the means for filtering the flow, at the top, in relation to the location of the pumping unit in the well, the washer is fixed with the possibility of abutment in the lower end surface of the coupling, designed to connect the pipe to the corresponding element of the pipe of the submersible pump unit, and a snap ring is installed in the lower part of the pipe to limit axial on the movement of the sleeve. 22. The device according to item 21, characterized in that two annular centralizers with a sphere-shaped outer surface are installed on the sleeve, between which sealing elements and annular spacers are placed alternating between each other, the upper centralizer is mounted with the possibility of abutment in the corresponding surface of the washer, and on the lower at the end of the sleeve, a thread is made on its outer surface and a nut is installed with the possibility of pressing the lower centralizer to the elements located between the centralizers to control the degree of initial formation of sealing elements. 23. The device according to p. 22, characterized in that the height of the spacers located between the elastic elements, measured in the axial direction is in the range from 0.25 to 0.75 of their diameter. 24. The device according to p. 22, characterized in that the outer diameter of the sealing elements is larger than the outer diameter of the spacers and less than the largest diameter of the centralizers, while the sealing elements are made of an elastic material capable of swelling in the environment of the reservoir fluid.