Sand blocking and discharging device for electric submersible pump

Abstract

The invention relates to the technical field of oil exploitation, in particular to a sand blocking and discharging device for an electric submersible pump, which comprises an outer pipe, a one-way valve, a core pipe, a first tubing coupling, an electric pump joint, a second tubing coupling and a valve protection cover, a one-way valve and a valve protection cover are arranged at the upper end of the core pipe, the upper end of the outer pipe is in threaded connection with the second tubing coupling, the lower end of the outer pipe is in threaded connection with the first tubing coupling and the electric pump connector, a rectangular through hole penetrating through the pipe wall is formed in the lower end of the core pipe, and a sliding block capable of sealing the through hole is arranged inside and limited by an upper clamping ring and a lower clamping ring. According to the sand blocking and discharging device for the electric submersible pump, sand-containing liquid falling back after the electric submersible pump is shut down is stored in the sand containing cavity, the liquid is precipitated, and therefore abrasion of the electric submersible pump is reduced, the one-way valve and the valve protection cover prevent sand and impurities from entering the electric submersible pump, and abrasion of residual liquid to the electric submersible pump after the electric submersible pump is shut down is reduced.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and in particular to a sand-blocking and sand-discharging device for submersible electric pumps. Background Technology

[0002] In the oil extraction field, submersible electric pumps (SAPs) are an important type of oil production equipment, widely used in rodless downhole mechanical oil production operations. The main function of SSPs is to mechanically pump fluids, such as crude oil and water, from the well to the surface. With the increasing scale of unconventional oil reservoir development, SSPs have become one of the main artificial lift devices in the initial stages of production.

[0003] Under current technological conditions, when using submersible electric pumps (SAPs) for mechanical oil recovery, fracturing sand in artificial reservoirs can easily be transported out by the high-speed flow of well fluid and enter the wellbore. Once the SSP stops operating, the fracturing sand in the wellbore will fall back due to gravity and remain inside the SSP's impeller. When the SSP restarts, this retained fracturing sand can cause the impeller to jam, leading to overload shutdown. This situation occurs frequently, not only affecting the unit's uptime but also jeopardizing continuous oil well production. Summary of the Invention

[0004] (a) Technical problems to be solved This invention provides a sand-blocking and sand-discharging device for submersible electric pumps, which overcomes the problem in the prior art where fracturing sand falls back into the wellbore and gets stuck in the submersible electric pump impeller during oil production, causing sand jamming and overload shutdown upon restart.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides a sand-blocking and sand-discharging device for a submersible electric pump, comprising: an outer pipe, a one-way valve, a core pipe, a first oil pipe coupling, an electric pump connector, a second oil pipe coupling, and a valve protective cover; The outer tube is sleeved over the core tube, and the annular gap formed by the outer tube and the core tube is a sand-containing cavity; The upper end of the core tube is provided with a one-way valve, and the one-way valve is provided with a valve protective cover. The lower end of the core tube wall is provided with several long strip-shaped slits. The upper end of the outer tube is threaded to a second oil pipe coupling, the lower end of the outer tube is threaded to a first oil pipe coupling, and the lower end of the first oil pipe coupling is threaded to an electric pump connector. The lower end of the core tube is provided with a rectangular through hole that completely penetrates both sides of the tube wall. Inside the core tube is a slider that can completely seal the rectangular through hole. The slider is limited by an upper retaining ring and a lower retaining ring located on the inner wall of the core tube.

[0006] Preferably, the one-way valve includes: a valve cavity, a valve body, a valve stem support, a valve stem, a lower valve stem guide ring, an upper valve stem guide ring, a valve cover, a spring, a spring cover, a valve disc, and a valve seat; Both the valve cavity and the valve body have a streamlined structure, with the valve body being round at the bottom and pointed at the top, allowing the fluid to flow stably within the valve cavity.

[0007] Preferably, the inner wall of the valve body is provided with an inwardly extending valve stem support, the valve stem support is provided with a lower valve stem guide ring at its center, the lower valve stem guide ring is provided with a valve stem, and the upper end of the valve stem is provided with a valve cover, which can completely seal the upper end of the valve body.

[0008] Preferably, the valve stem has a cylindrical structure, and the lower end of the valve stem has a step on the outer edge. The valve stem passes through the center of the valve disc and is tightly fixed to the locking cap and the valve disc through the step. A sealing ring is provided between the step and the valve disc, and a spring is sleeved on the outer wall of the locking cap.

[0009] Preferably, a valve seat is threadedly connected to the upper end of the inner wall of the valve body, and an upper valve stem guide ring is provided at the center of the valve seat. The upper end of the valve stem is embedded in the upper valve stem guide ring, and a spring cover is provided at the lower end of the valve seat. The inner diameter of the spring cover is the same as the outer diameter of the valve disc. When the valve disc is opened upward by liquid pressure, it can seal the spring cover so that the spring is not affected by the liquid.

[0010] Preferably, the elongated slit is used to filter the liquid in the sand chamber, so that the liquid can smoothly enter the core tube while impurities remain in the sand chamber.

[0011] Preferably, the lower end of the electric pump connector is used to connect to the submersible electric pump, the upper end of the second oil pipe coupling is used to connect to the oil pipe, and the upper and lower retaining rings provided on the inner wall of the core tube are annular steps extending inward from the inner wall of the core tube.

[0012] Preferably, the slider in the core tube has a hollow structure at the top and a circular force-bearing surface at the center. When liquid enters the core tube through the electric pump connector, the slider can move upward under the impact of the liquid to the upper retaining ring to open the rectangular through hole at the lower end of the core tube. When the submersible electric pump stops, the slider falls back to the lower retaining ring to seal the rectangular through hole at the lower end of the core tube.

[0013] Preferably, the valve protective cover is a hollow cylindrical structure with several rectangular through holes on its outer wall. The lower end of the valve protective cover is threaded to a one-way valve, and the upper end of the valve protective cover is provided with a cover top with rounded corners. The cover top is used to divert the liquid falling back in the oil pipe to reduce the impact on the top of the one-way valve and reduce liquid residue.

[0014] (III) Beneficial Effects This invention provides a sand-blocking and sand-discharging device for a submersible electric pump. It can store sand-containing liquid that falls back from the oil pipe after the submersible electric pump stops by forming an annular sand-containing cavity between the outer tube and the core tube. The sand-containing liquid settles in the sand-containing cavity, and the cleaner liquid enters the core tube through a long strip-shaped slit on the outer wall of the core tube to reduce the wear of the submersible electric pump caused by the residual liquid after shutdown. This device uses a one-way valve and valve guard to prevent sand and other impurities from entering the submersible pump, which helps to extend the service life of the submersible pump and reduce the failure rate. The opening and closing state of the rectangular through hole is controlled by a slider. When the submersible pump is turned on, the slider opens upward to discharge sand. When the submersible pump is turned off, the slider falls back to prevent sand and other impurities in the sand chamber from entering the submersible pump through the core tube. The components of the device are connected by threads, which makes the installation and disassembly of the device simple and convenient for on-site maintenance and repair. Attached Figure Description

[0015] Figure 1 This diagram shows a sand-blocking and sand-discharging device for a submersible electric pump according to the present invention. Figure 2 This diagram shows a one-way valve structure of a sand-blocking and sand-discharging device for a submersible electric pump according to the present invention. Figure 3 This diagram shows a schematic of the slider structure of a sand-blocking and sand-discharging device for a submersible electric pump according to the present invention. Figure 4 Show Figure 1 Enlarged schematic diagram of part of structure A in the middle; Figure 5 Show Figure 1 A magnified schematic diagram of a portion of the B-structure.

[0016] Wherein: 1: outer tube; 11: sand chamber; 2: one-way valve; 21: valve chamber; 22: valve body; 23: valve stem support column; 24: valve stem; 25: lower valve stem guide ring; 26: upper valve stem guide ring; 27: valve cover; 28: spring; 29: spring cover; 210: valve disc; 211: valve seat; 3: core tube; 31: long strip slit; 32: upper retaining ring; 33: lower retaining ring; 34: slider; 4: first oil pipe coupling; 5: electric pump connector; 6: second oil pipe coupling; 7: valve protective cover. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "inner," "outer," "top," and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings. They are intended only to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the components referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] like Figure 1-5 As shown, the present invention provides a sand-blocking and sand-discharging device for a submersible electric pump, comprising: an outer pipe 1, a one-way valve 2, a core pipe 3, a first oil pipe coupling 4, an electric pump connector 5, a second oil pipe coupling 6, and a valve protective cover 7. The outer tube 1 is a hollow cylindrical structure. The inner diameter of the outer tube 1 is larger than the outer diameter of the core tube 3 so that the core tube 3 can be accommodated therein. The outer tube 1 is sleeved on the outside of the core tube 3. The annular gap formed between the outer tube 1 and the core tube 3 is a sand-containing cavity 11. The sand-containing cavity 11 is used to store the sand-containing liquid that falls back from the oil pipe after the submersible electric pump stops.

[0020] The one-way valve 2 includes: valve chamber 21, valve body 22, valve stem support 23, valve stem 24, lower valve stem guide ring 25, upper valve stem guide ring 26, valve cover 27, spring 28, spring cover 29, valve disc 210, and valve seat 211. Both the valve cavity 21 and the valve body 22 have streamlined structures, with the valve body 22 being round at the bottom and pointed at the top. This allows fluid to flow smoothly within the valve cavity 21, reducing resistance and turbulence. The inner wall of the valve body 22 has an inwardly extending valve stem support 23. A lower valve stem guide ring 25 is located at the center of the valve stem support 23, and a valve stem 24 is housed within the lower valve stem guide ring 25. The valve stem 24 has a cylindrical structure, with a stepped outer edge on its lower outer wall. The valve stem 24 passes through the center of the valve disc 210 and is tightly fixed to the locking cap 212 and the valve disc 210 via the step. A sealing ring is provided between the step and the valve disc 210. A spring 28 is fitted on the outer wall of the locking cap 212. A valve cover 27 is provided at the upper end of the valve stem 24. The valve cover 27 can completely seal the upper end of the valve body 22. The valve stem 24 and the valve cover 27 are integrally formed. A valve seat 211 is threadedly connected to the upper end of the inner wall of the valve body 22. An upper valve stem guide ring 26 is provided at the center of the valve seat 211. The upper end of the valve stem 24 is embedded in the upper valve stem guide ring 26. A spring cover 29 is provided at the lower end of the valve seat 211. The inner diameter of the spring cover 29 is the same as the outer diameter of the valve disc 24. When the valve disc 24 is opened upward by liquid pressure, it can seal the spring cover 29 so that the spring 28 is not affected by the liquid. When the liquid enters the core tube 3 from the electric pump connector 5, the pressure of the liquid acts on the valve disc 210. The valve disc 210 rises against the elastic force of the spring 28, and the liquid can enter the oil pipe through the valve chamber 21. As the liquid continues to flow in, the valve disc 210 continues to open, and the liquid can pass through quickly. When the pump stops working, the spring 28 pushes the valve disc 210 to reseal the lower end of the valve body 22. At the same time, the valve cover 27 falls back to seal the upper end of the valve body 22 under the action of elastic force, preventing the sand-containing liquid in the oil pipe from flowing back into the core tube 3.

[0021] The core tube 3 is hollow inside and is used to transport the liquid extracted from the bottom of the well. It is equipped with a one-way valve 2 at its upper end to allow the liquid to flow in while preventing the liquid from flowing back. The one-way valve 2 is equipped with a valve protection cover 7, which is a hollow cylindrical structure. It protects the one-way valve 2 from the impact of high-pressure liquid and the wear of impurities. The outer wall of the valve protection cover 7 is provided with several rectangular through holes. These through holes allow the liquid to flow out of the one-way valve 2 and into the oil pipe. The lower end of the valve protection cover 7 is connected to the one-way valve 2 by threads. The upper end of the valve protection cover 7 is designed with a rounded top. This design helps to divert the liquid falling back from the oil pipe, reduce the impact force on the top of the one-way valve 2, and reduce the liquid residue on the top of the one-way valve 2. The lower end of the core tube 3 has several elongated slits 31 on its tube wall. These elongated slits 31 are used to filter the liquid in the sand chamber 11, allowing smaller particles and liquid to pass through, while larger impurities are left to settle in the sand chamber 11. The upper end of the outer tube 1 is connected to the second oil pipe coupling 6 by a thread. The upper end of the second oil pipe coupling 6 is used to connect the oil pipe. The lower end of the outer tube 1 is connected to the first oil pipe coupling 4 by a thread. The lower end of the first oil pipe coupling 4 is further connected to the electric pump connector 5 by a thread. The lower end of the electric pump connector 5 is used to connect the submersible electric pump. The lower end of the core tube 3 has a rectangular through-hole that completely penetrates both sides of the tube wall. Inside the core tube 3 is a slider 34, which can move along the length of the core tube 3 and completely seal the rectangular through-hole. The top of the slider 34 is designed with a hollow structure to reduce its weight and allow liquid to pass through. A circular force-bearing surface is located at the center of this hollow structure to provide a stable force point, enabling the slider 34 to move stably under liquid pressure. When liquid is pressurized through the electric pump connector 5 and enters the core tube 3, the slider 34 is impacted by the liquid and can move upwards. When the upper retaining ring 32 is in position, the rectangular through hole at the lower end of the core tube 3 is opened to discharge the sand and gravel impurities deposited in the sand-containing cavity 11 between the core tube 3 and the outer tube 1. When the submersible pump stops, due to gravity, the slider 34 will automatically fall back onto the lower retaining ring 33. At this time, the slider seals the rectangular through hole at the lower end of the core tube 3, preventing the sand-containing liquid falling from the oil pipe from entering the core tube 3 through the sand-containing cavity 11. The slider 34 is limited by the upper retaining ring 32 and the lower retaining ring 33 provided on the inner wall of the core tube 3. The upper retaining ring 32 and the lower retaining ring 33 provided on the inner wall of the core tube 3 are annular steps extending inward from the inner wall of the core tube 3.

[0022] The following is a detailed description of the actual working scenario of the sand-blocking and sand-removing device used in submersible electric pumps.

[0023] In practical work, the sand-blocking and sand-discharging device used for submersible electric pumps is vertically installed in the oil well. When the submersible electric pump is working, the liquid is pumped from the bottom of the well by the submersible electric pump, and after being pressurized through the electric pump connector 5, it enters the core tube 3. The liquid pressure in the core tube 3 pushes the slider 34 to move upward until it reaches the position of the upper retaining ring 32. This causes the rectangular through hole at the lower end of the core tube 3 to open. The opened rectangular through hole allows the sand and gravel deposited in the sand-containing cavity 11 to be discharged upward along with the liquid in the core tube 3. When the liquid pressure acts on the valve disc 210 of the one-way valve 2, the valve disc 210 overcomes the elastic force of the spring 28 and rises. The liquid can then enter the oil pipe through the valve cavity 21, realizing the function of starting the device to discharge sand. When the submersible pump stops working, the liquid is no longer pressurized and pumped up. Therefore, the slider 34 automatically falls back to the position of the lower retaining ring 33 due to gravity, sealing the rectangular through hole at the lower end of the core tube 3. This prevents the liquid in the sand-containing chamber 11 from directly entering the core tube 3. At the same time, under the action of the spring, the valve disc 210 closes the lower end of the valve body 22, and the valve cover 27 falls back to close the upper end of the valve body 22, completely sealing the upper end of the core tube 3. This prevents the liquid in the oil pipe from falling into the core tube 3 and affecting the operation of the submersible pump, thus achieving the function of sand blocking when the device stops.

[0024] It is understood that the various embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0025] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0026] The sand-blocking and sand-discharging device for submersible electric pumps provided by the present invention enables the storage of sand-containing liquid that falls back from the oil pipe after the submersible electric pump stops through the annular sand-containing cavity 11 formed between the outer pipe 1 and the core pipe 3. The sand-containing liquid settles in the sand-containing cavity 11, and the cleaner liquid enters the core pipe 3 through the elongated slit 31 provided on the outer wall of the core pipe 3, thereby reducing the wear of the submersible electric pump caused by the residual liquid after shutdown. The device prevents sand and other impurities from entering the submersible pump by using a one-way valve 2 and a valve cover 7, which helps to extend the service life of the submersible pump and reduce the failure rate. The opening and closing state of the rectangular through hole is controlled by the slider 34. When the submersible pump is turned on, the slider 34 opens upward to discharge sand. When the submersible pump is turned off, the slider 34 falls back to prevent sand and other impurities in the sand chamber 11 from entering the submersible pump through the core tube 3. The components of the device are connected by threads, which makes the installation and disassembly of the device simple and convenient for on-site maintenance and repair.

[0027] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A sand-blocking and sand-discharging device for a submersible electric pump, characterized in that, include: Outer pipe (1), one-way valve (2), core pipe (3), first oil pipe coupling (4), electric pump connector (5), second oil pipe coupling (6) and valve protective cover (7); The outer tube (1) is sleeved on the outside of the core tube (3), and the annular gap formed by the outer tube (1) and the core tube (3) is a sand-containing cavity (11). The upper end of the core tube (3) is provided with a one-way valve (2), and the one-way valve (2) is provided with a valve protection cover (7). The lower end of the core tube (3) is provided with several long strip-shaped slits (31). The upper end of the outer tube (1) is threaded to the second oil pipe coupling (6), the lower end of the outer tube (1) is threaded to the first oil pipe coupling (4), and the lower end of the first oil pipe coupling (4) is threaded to the electric pump connector (5). The lower end of the core tube (3) is provided with a rectangular through hole that completely penetrates both sides of the tube wall. The core tube (3) is provided with a slider (34) that can completely seal the rectangular through hole. The slider (34) is limited by an upper retaining ring (32) and a lower retaining ring (33) provided on the inner wall of the core tube (3).

2. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 1, characterized in that, The one-way valve (2) includes: valve chamber (21), valve body (22), valve stem support (23), valve stem (24), lower valve stem guide ring (25), upper valve stem guide ring (26), valve cover (27), spring (28), spring cover (29), valve disc (210), and valve seat (211). Both the valve cavity (21) and the valve body (22) are streamlined structures. The valve body (22) is round at the bottom and pointed at the top, allowing the fluid to flow stably in the valve cavity (21).

3. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 2, characterized in that, The valve body (22) has an inwardly extending valve stem support (23) on its inner wall. The valve stem support (23) has a lower valve stem guide ring (25) at its center. The lower valve stem guide ring (25) has a valve stem (24) in it. The valve stem (24) has a valve cover (27) at its upper end. The valve cover (27) can completely seal the upper end of the valve body (22).

4. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 2, characterized in that, The valve stem (24) is a cylindrical structure. The lower end of the valve stem (24) has a step on the outer edge. The valve stem (24) passes through the center of the valve disc (210) and is tightly fixed to the locking cap (212) and the valve disc (210) through the step. A sealing ring is provided between the step and the valve disc (210). A spring (28) is sleeved on the outer wall of the locking cap (212).

5. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 2, characterized in that, The valve body (22) has a valve seat (211) threadedly connected to the upper end of its inner wall. The valve seat (211) has an upper valve stem guide ring (26) at its center. The upper end of the valve stem (24) is embedded in the upper valve stem guide ring (26). The lower end of the valve seat (211) has a spring cover (29). The inner diameter of the spring cover (29) is the same as the outer diameter of the valve disc (24). When the valve disc (24) opens upward under liquid pressure, it can seal the spring cover (29) so that the spring (28) is not affected by the liquid.

6. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 1, characterized in that, The elongated slit (31) is used to filter the liquid in the sand chamber (11), so that the liquid can smoothly enter the core tube (3) while impurities remain in the sand chamber (11).

7. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 1, characterized in that, The lower end of the electric pump connector (5) is used to connect to the submersible electric pump, and the upper end of the second oil pipe coupling (6) is used to connect to the oil pipe. The upper retaining ring (32) and the lower retaining ring (33) provided on the inner wall of the core tube (3) are annular steps extending inward from the inner wall of the core tube (3).

8. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 7, characterized in that, The slider (34) provided in the core tube (3) has a hollow structure at the top and a circular force-bearing surface at the center. When liquid enters the core tube (3) through the electric pump connector (5), the slider (34) can move upward to the upper retaining ring (32) under the impact of the liquid and open the rectangular through hole provided at the lower end of the core tube (3). When the submersible electric pump stops, the slider (34) falls back to the lower retaining ring (33) and seals the rectangular through hole provided at the lower end of the core tube (3).

9. The sand-blocking and sand-discharging device for a submersible electric pump according to claim 7, characterized in that, The valve cover (7) is a hollow cylindrical structure with several rectangular through holes on its outer wall. The lower end of the valve cover (7) is threaded to the check valve (2). The upper end of the valve cover (7) is provided with a cover top with rounded corners. The cover top is used to divert the liquid falling back in the oil pipe to reduce the impact on the top of the check valve (2) and reduce liquid residue.

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