Downhole ball fishing device of concentric pipe jet pump

Abstract

The invention discloses an underground ball fishing device of a concentric tube jet pump. The device comprises a concentric pipe hydraulic jet pump, a pump cylinder and an outer layer oil pipe are tripped into a well together, a pump core is thrown into the well through a center oil pipe, a valve ball is arranged at the upper end of the concentric pipe hydraulic jet pump, and a necking shaft and a conical valve ball fishing head are sequentially arranged at the upper end of the valve ball; a catching assembly and a lifting assembly of the ball fishing device are sequentially connected from bottom to top, during valve ball fishing operation, the ball fishing device is put into a well to the position above a valve ball in a pump cylinder of the concentric pipe jet pump till a valve ball fishing head enters a catching cylinder at the lower end of the catching assembly, a spring piece at the lower end of the catching cylinder is clamped at a necking shaft of the valve ball, a reverse circulation mode is started, and the valve ball fishing head is lifted. And the ball fishing device moves upwards to separate the valve ball from the valve seat under the hydraulic action. The invention has the beneficial effects that the structural design is reasonable, the valve ball in the underground pump cylinder is captured, and the valve ball is separated from the valve seat or carried to the ground through an oil pipe by utilizing reverse circulation hydraulic power; the operation difficulty is reduced, the operation frequency is reduced, and the non-production operation time is shortened.

Description

Technical Field

[0001] This invention relates to a downhole retrieval device, and more particularly to a downhole ball retrieval device for a concentric tube jet pump, belonging to the field of oil and gas development technology. Background Technology

[0002] With the continuous development of oil and gas fields, the number of highly deviated and horizontal wells is gradually increasing. Traditional rod-driven well production processes are limited in complex well conditions, and rod string wear becomes increasingly apparent. To address this challenge, rodless well production processes have developed rapidly. Among these, concentric tubular hydraulic jet pumps are gaining popularity due to their deep pumping depth, strong sand-carrying capacity, high fluid production, wide application range, and suitability for high gas-liquid ratios. To adapt to different well conditions, concentric tubular hydraulic jet pump technology is undergoing continuous product iteration and upgrades, making the development of supporting tools increasingly important. Downhole valve ball retrieval tools are one such supporting tool. Currently, the valve ball of the concentric tube jet pump cannot be retrieved separately. During the operation of pulling out the downhole tubing and pump barrel, because the valve ball cuts off the channel for the well fluid in the tubing to flow back downhole, the well fluid will be pulled out along with the tubing and pump barrel. Whenever a section of tubing is disassembled, the well fluid will overflow from the connection point. In order to avoid environmental pollution, special personnel and special equipment are required to collect it and then inject it downhole. The operation process is time-consuming, labor-intensive, inefficient, and increases non-production operation time. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings of the existing concentric tube hydraulic jet pump valve ball retrieval technology, the present invention provides a concentric tube jet pump downhole ball retrieval device.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: This invention provides a concentric tube hydraulic jet pump downhole ball retrieval device, including a concentric tube hydraulic jet pump, the pump barrel and outer tubing are lowered downhole together, the pump core is lowered downhole through the central tubing, and the valve ball is set at the upper end of the concentric tube hydraulic jet pump; the upper end of the valve ball is sequentially provided with a necking shaft and a conical valve ball retrieval head; the retrieval device's capture assembly and lifting assembly are connected sequentially from bottom to top; during valve ball retrieval operation, the ball retrieval device is lowered downhole into the pump barrel of the concentric tube jet pump until the valve ball retrieval head enters the capture cylinder at the lower end of the capture assembly, the spring plate at the lower end of the capture cylinder is locked at the necking shaft of the valve ball, the reverse circulation mode is activated, and under the action of hydraulic force, the ball retrieval device moves upward to disengage the valve ball from the valve seat.

[0005] The upper connector, connecting column, retrieval tube connector, and retrieval tube short section of the capture assembly are connected sequentially from top to bottom.

[0006] Furthermore, the upper connector is provided with a radial vent hole, and a radial sealing ring is provided on the outer circumference of the upper connector, with the radial sealing ring located below the vent hole.

[0007] Furthermore, a capture cylinder is provided inside the scooping cylinder section at the lower end of the capture assembly, and a spring is provided axially between the capture cylinder and the scooping cylinder joint at its upper end.

[0008] Furthermore, the lower end of the capture tube is a thin-walled tube with an inner boss at the lower end; the thin-walled tube is provided with a radial through groove, so that the lower end of the capture tube becomes two or more spring plates.

[0009] Furthermore, the capture tube is provided with a release hole I, and the short section of the scooping tube is provided with a radial release hole II. When the radial release hole I and the radial release hole II are connected, the liquid in the capture tube is discharged.

[0010] The upper connector of the capture assembly is fixedly connected to the lower end of the lifting assembly's short section.

[0011] The lifting assembly consists of a lifting and retrieval head, a transition section, a straightening section, and a lifting section connected sequentially from top to bottom.

[0012] The forced-start section is equipped with a forced-start valve. When the ball-retrieving device is separated from the pump cylinder, the forced-start valve closes, cutting off the liquid flow channel inside the ball-retrieving device.

[0013] The outer circumference of the straightening section is equipped with a leather cup and a locking nut for fixing the leather cup.

[0014] The lifting and retrieval head is equipped with a radial liquid inlet hole.

[0015] The beneficial effects of this invention are: a reasonable structural design that captures the valve ball inside the downhole pump barrel and uses reverse circulation hydraulic force to detach the valve ball from the valve seat or carry it to the surface through the tubing; the lower end of the lifting assembly can be connected to the production pump core assembly, pressure testing pump core assembly, etc., for production operation processes, pressure testing operation processes, or other supporting operation processes; the modular design reduces production costs; during well workover operations in jet pump wells, the ball retrieval device can be used as an oil drainer to release the central tubing channel, enabling oil and gas well self-flowing, gas lift, and foam drainage operations; it reduces operational difficulty, decreases the number of operations, shortens non-production operation time, and is safe and environmentally friendly. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the concentric tube jet pump downhole ball retrieval device of the present invention.

[0017] Figure 2 This is a schematic diagram of the capture assembly in this invention.

[0018] Figure 3 This is a schematic diagram of the retrieval operation of the concentric tube jet pump well ball retrieval device of the present invention.

[0019] Figure 4 This is a schematic diagram of the valve ball structure of the present invention.

[0020] In the diagram: 1. Upper connector, 2. Drain hole, 3. Radial sealing ring, 4. Connecting tubing string, 5. Intermediate connector, 6. Short section, 7. Retrieval tube connector, 8. Retrieval tube short section, 9. Spring, 10. Release hole II, 11. Release hole I, 12. Capture tube, 13. Spring plate, 14. Capture assembly, 15. Lifting and retrieval head, 16. Radial inlet hole, 17. Transition short section, 18. Locking nut, 19. Leather cup, 20. Straightening short section, 21. Forced lifting short section, 22. Forced lifting valve, 23. Lifting assembly, 24. Pump barrel, 25. Valve ball, 26. Necked shaft, 27. Valve ball retrieval head, 28. Radial through groove; 29. ​​Inlet channel. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. However, those skilled in the art should understand that the present invention is not limited to the specific embodiments listed, and any embodiment that conforms to the spirit of the present invention should be included within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "vertical", "up", "down", "left", "right", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing or simplifying the description of this invention, and do not indicate or imply that the device or element 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.

[0023] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "seal" should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium, or it can be a connection between the internal parts of two components. A seal can be an oil seal, a packing seal, or other forms of seal. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] See appendix Figure 1-4 This invention discloses a downhole ball retrieval device for a concentric tube hydraulic jet pump, comprising a concentric tube hydraulic jet pump, a pump barrel 24 lowered into the well along with the outer tubing, a pump core inserted into the well through the central tubing, and a valve ball 25 positioned at the upper end of the concentric tube hydraulic jet pump; the upper end of the valve ball 25 is sequentially provided with a necked shaft 26 and a conical valve ball retrieval head 27 (e.g., ...). Figure 4 (As shown).

[0025] The ball-catching device includes a capture assembly 14 and a lifting assembly 23, which are connected sequentially from bottom to top. The capture assembly 14 is used to capture the valve ball 25, and the lifting assembly 23 is used to lift the ball-catching device.

[0026] When retrieving the valve ball 25, the ball retrieval device is lowered into the concentric tube jet pump cylinder 24 until the valve ball retrieval head 27 enters the capture cylinder 12 at the lower end of the capture assembly 14. The spring plate 13 at the lower end of the capture cylinder 12 is locked at the constriction shaft 26 of the valve ball 25. The reverse circulation mode is activated, and under the action of hydraulic force, the ball retrieval device moves the valve ball 25 upward to disengage from the valve seat.

[0027] See appendix Figure 2 The upper connector 1, connecting column 4, retrieval tube connector 7, and retrieval tube short section 8 of the capture assembly 14 are fixedly connected from top to bottom, usually using a threaded connection. The length of the connecting column 4 is determined according to the length required by the retrieval tool; preferably, the connecting column 4 is composed of one or more intermediate connectors 5 and two or more short sections 6.

[0028] The upper connector 1 is provided with radial drain holes 2, and a radial sealing ring 3 is provided on the outer circumference of the upper connector 1, located below the drain holes 2. Preferably, there are four drain holes 2, evenly distributed along the circumference of the upper connector 1. When the ball-retrieving device moves upward away from the pump cylinder 24, the liquid above the ball-retrieving device is discharged from the ball-retrieving device. When the ball-retrieving device enters the pump cylinder 24, a seal is formed between the radial sealing ring 3 and the inner hole of the pump cylinder 24, sealing the annular channel between the outer circumference of the ball-retrieving device and the inner wall of the pump cylinder 24.

[0029] A capture cylinder 12 is provided inside the scooping cylinder short section 8 at the lower end of the capture assembly 14. A spring 9 is provided axially between the capture cylinder 12 and the scooping cylinder joint 7 at its upper end, which plays a buffering role when capturing the valve ball 25.

[0030] The lower end of the capture tube 12 is a thin-walled tube with an inner boss at the lower end. The thin-walled tube has two or more radial through grooves 28, so that the lower end of the capture tube 12 becomes two or more spring plates 13. The spring plates 13 are arc-shaped, and multiple arc-shaped spring plates 13 form a cylindrical shape. When the conical valve ball retrieval head 27 at the upper end of the valve ball 25 enters the capture tube 12, the inner boss at the lower end of the spring plate 13 jams the necking shaft 26, preventing the valve ball 25 from moving downward.

[0031] The capture cylinder 12 is provided with a release hole I11, and the scooping cylinder section 8 is provided with a radial release hole II10. When the radial release hole I11 and the radial release hole II10 are connected, the liquid entering the capture cylinder 12 will be discharged from the ball scooping device.

[0032] The upper connector 1 at the upper end of the capture assembly 14 is fixedly connected to the lifting section 21 of the lifting assembly 23. Preferably, the upper connector 1 and the lifting section 21 are connected by a thread (as shown in the attached diagram). Figure 1 (As shown).

[0033] The lifting assembly 23 consists of a lifting and retrieval head 15, a transition section 17, a straightening section 20, and a lifting section 21 connected sequentially from top to bottom, typically using a threaded connection.

[0034] The forced-lifting section 21 is equipped with a forced-lifting valve 22. When the ball-retrieving device is separated from the pump cylinder 24, the forced-lifting valve 22 closes, cutting off the liquid flow channel in the ball-retrieving device and increasing the force with which the ball-retrieving device is separated from the pump cylinder 24.

[0035] The outer circumference of the straightening sub 20 is provided with a cup 19 and a locking nut 18, which fixes the cup 19 axially; preferably, the locking nut 18 is located above the cup. When the ball-retrieval device is lifted, the cup 19 is used to increase the upward thrust of the liquid on the ball-retrieval device, so that the ball-retrieval device can reach the wellhead smoothly.

[0036] The lifting and retrieval head 15 is provided with radial liquid inlet holes 16. Preferably, there are two or more radial liquid inlet holes 16, which are evenly distributed along the circumference of the lifting and retrieval head 15.

[0037] The concentric tube jet pump downhole string comprises two layers of tubing: a central tubing and an outer tubing. During forward circulation, high-pressure fluid is injected through the central tubing and returns to the surface through the annulus between the two tubing layers. During reverse circulation, high-pressure fluid is injected through the annulus between the two tubing layers and returns to the surface through the central tubing. The concentric tube jet pump comprises a pump barrel and a pump core. The pump barrel is lowered into the well along with the outer tubing, while the pump core is lowered into the well through the central tubing. A sealing plug is connected to the lower end of the central tubing, which is lowered into the well along with the central tubing and inserted into the pump barrel to form a seal and production flow channel. The inner diameter of the sealing plug is smaller than the maximum outer diameter of the lifting assembly (not shown in the figure).

[0038] See appendix Figure 3 The downhole ball retrieval device for the concentric tube jet pump of the present invention is used to perform the following downhole valve ball retrieval operation:

[0039] First, the ball retrieval device is deployed from the wellhead, and high-pressure fluid is injected in a positive circulation manner. The high-pressure fluid propels the ball retrieval device downward along the central tubing, into the jet pump barrel, and reaches above the valve ball 25. Relying on the downward impact force of the high-pressure fluid and gravity, the spring plate 13 at the lower end of the capture tube 12 collides with the valve ball retrieval head 27. Since the valve ball retrieval head 27 adopts a conical design, under the action of the impact force, the spring plate 13 of the valve ball retrieval head 27 opens outward, and the valve ball retrieval head 27 enters the short section 8 of the retrieval tube. Because the diameter of the necking shaft 26 is smaller than the maximum diameter of the valve ball retrieval head 27, the spring plate 13 begins to contract and clamp the necking shaft 26. The capture tube 12 completes the capture of the valve ball 25, making it impossible for the valve ball 25 to detach from the capture tube 12.

[0040] Afterwards, the gas / oil tree valves are switched, and reverse circulation injection is performed. Under the combined flow-blocking action of the radial sealing ring 3, the forced-lift valve 22, and the piston cup 19, the high-pressure fluid pushes the ball-retrieval device upwards until it detaches from the pump cylinder 24, carrying the valve ball 25 upwards along the central tubing until it reaches the wellhead. Then, the wellhead tool captures the pump core retrieval head 15 and removes the ball-retrieval device and valve ball. At this point, the central tubing is connected to the fluid inlet channel 29, facilitating other drainage operations. If a wireline retrieval method is used, there is no need to perform reverse circulation injection of fluid downhole; the ball-retrieval device and valve ball can be removed directly by pulling up the wireline.

[0041] When well workover operations are required, the ball retrieval device captures the valve ball 25 and pulls it out of the wellbore without reverse circulation. The workover vehicle then directly lifts the central tubing, pulling the ball retrieval device, valve ball, and central tubing out of the wellbore together. Because the inner diameter of the sealing plug is smaller than the maximum diameter of the ball retrieval device, the ball retrieval device is pulled out along with the central tubing when the tubing is lifted. The ball retrieval device also functions as a drain; liquid at the upper end of the ball retrieval device enters the internal flow channel of the ball retrieval device through the radial inlet hole 16, flows through the drain hole 2 to the lower end of the ball retrieval device, and then enters the bottom of the well through the inlet channel 29, preventing well site contamination.

[0042] This invention relates to a concentric tubing jet pump downhole ball retrieval device. The device is inserted from the wellhead and flows downwards along the central tubing into the jet pump barrel. Through forward circulation injection and the downward impact of gravity, the valve ball is forced into a capture tube and locked in place, preventing it from detaching. Then, reverse circulation injection utilizes the upward thrust of the liquid to detach the downhole ball retrieval device from the jet pump barrel, lifting it to the surface and retrieving the valve ball. This releases the central tubing passage, facilitating other drainage operations. During well workover, there is no need to lift the downhole ball retrieval device to the surface; after the valve ball detaches from its seat, it is retrieved along with the central tubing. During the lifting of the central tubing, the ball retrieval device acts as an oil drainer, preventing well site pollution and ensuring safety and environmental protection.

[0043] This invention includes a lifting assembly and a capture assembly. The production tubing can be connected to production pump cores, pressure testing pump cores, and other jet pump downhole devices to form other supporting devices for the jet pump. The modular design can reduce production costs. During well workover operations, the ball retrieval device can be used as an oil drainer, reducing operational difficulty and ensuring safety and environmental protection. It can release the central tubing channel to realize oil and gas well self-flowing, gas lift, and foam drainage processes, reducing the number of operations, effectively reducing operating costs, and expanding the applicability of jet pump drainage technology in oil and gas fields.

[0044] It should be noted that the above embodiments are examples and not limitations of the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A downhole ball retrieval device for a concentric tube hydraulic jet pump, comprising a concentric tube hydraulic jet pump, wherein the pump barrel and outer tubing are lowered downhole together, the pump core is lowered downhole through the central tubing, and a valve ball is disposed at the upper end of the concentric tube hydraulic jet pump; characterized in that: The upper end of the valve ball is provided with a necked shaft and a conical valve ball retrieval head in sequence. The ball retrieval device's capture assembly and lifting assembly are connected sequentially from bottom to top. When retrieving the valve ball, the ball retrieval device is lowered into the concentric tube jet pump barrel until the valve ball retrieval head enters the capture tube at the lower end of the capture assembly. The spring plate at the lower end of the capture tube is locked at the valve ball's constriction shaft, and the reverse circulation mode is activated. Under the action of hydraulic force, the ball retrieval device moves upward to disengage the valve ball from the valve seat.

2. The downhole ball retrieval device for a concentric tube jet pump according to claim 1, characterized in that: The upper connector, connecting column, retrieval tube connector, and retrieval tube short section of the capture assembly are connected sequentially from top to bottom.

3. The concentric tube jet pump downhole ball retrieval device according to claim 2, characterized in that: The upper connector is provided with a radial vent hole, and a radial sealing ring is provided on the outer circumference of the upper connector, with the radial sealing ring located below the vent hole.

4. The downhole ball retrieval device for a concentric tube jet pump according to claim 2, characterized in that: A capture cylinder is installed inside the scooping cylinder section at the lower end of the capture assembly, and a spring is installed axially between the capture cylinder and the scooping cylinder joint at its upper end.

5. The downhole ball retrieval device for a concentric tube jet pump according to claim 3, characterized in that: The lower end of the capture tube is a thin-walled tube with an inner boss at the lower end; the thin-walled tube is provided with a radial through groove, so that the lower end of the capture tube becomes two or more spring plates.

6. The downhole ball retrieval device for a concentric tube jet pump according to claim 1, characterized in that: The capture tube is provided with a release hole I, and the short section of the scooping tube is provided with a radial release hole II. When the radial release hole I and the radial release hole II are connected, the liquid in the capture tube is discharged.

7. The downhole ball retrieval device for a concentric tube jet pump according to claim 1, characterized in that: The upper connector of the capture assembly is fixedly connected to the lower end of the lifting assembly's short section; The lifting assembly consists of a lifting and salvage head, a transition section, a straightening section, and a lifting section connected sequentially from top to bottom. The forced-start section is equipped with a forced-start valve. When the ball-retrieving device is separated from the pump cylinder, the forced-start valve closes, cutting off the liquid flow channel inside the ball-retrieving device.

8. The downhole ball retrieval device for a concentric tube jet pump according to claim 7, characterized in that: The outer circumference of the straightening section is equipped with a leather cup and a locking nut for fixing the leather cup.

9. The downhole ball retrieval device for a concentric tube jet pump according to claim 8, characterized in that: The lifting and retrieval head is equipped with a radial liquid inlet hole.

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