Two-way slip type single flow sealing downhole limiting device

Abstract

The application discloses a bidirectional slip type single-flow sealing downhole limiting device, which comprises a mandrel, a one-way sealing mechanism connected to one end of the mandrel, a sand prevention mechanism connected to the other end of the mandrel, a fishing head sleeved on the outer wall of the mandrel and close to the one-way sealing mechanism, a sliding sleeve connected to the end of the fishing head close to the one-way sealing mechanism, a lock sleeve connected to the end of the fishing head away from the one-way sealing mechanism, a clamping and releasing mechanism arranged between the lock sleeve and the mandrel, a plurality of through grooves (33) arranged on the outer wall of the end of the lock sleeve away from the clamping and releasing mechanism at equal intervals, a clamping mechanism arranged in each through groove (33) and on the outer wall of the mandrel, and a rubber cylinder mechanism arranged between the clamping mechanism and the sand prevention mechanism and on the outer wall of the mandrel. The limiting device solves the problems that the existing single-flow downhole limiting and clamping device cannot be applied to the jointless tubing and the fishing is not easy due to the liquid accumulation above.

Description

Technical Field

[0001] This invention belongs to the technical field of downhole limiting devices, specifically relating to a bidirectional slip-type single-flow sealing downhole limiting device. Background Technology

[0002] Plunger gas lift drainage technology has become an important drainage technology for gas fields, boasting advantages such as high intelligence, high drainage efficiency, long operating time, and low cost. For conventional plungers, downhole limiters are required. These limiters are categorized into two types based on fluid flow characteristics: non-single-flow and single-flow limiters. With non-single-flow limiters, fluid falls back to the wellbore during plunger operation, increasing bottomhole back pressure and reducing plunger efficiency. Therefore, downhole limiters with single-flow limiters are currently more commonly used. These limiters provide single-flow control while locking the plunger, ensuring fluid falls above the limiter, reducing bottomhole back pressure and improving plunger drainage efficiency. However, since it uses a spring-loaded locking device, the locking mechanism needs to be locked into the tubing coupling, making it only usable for tubing with couplings (EUE tubing) and not for tubing without couplings (FOX tubing). At the same time, when retrieval is required, the liquid accumulation above the downhole limit locking device with single-flow limiting function is large, which increases the working pulling force and makes it impossible to generate displacement and release normally, thus bringing great difficulties to retrieval.

[0003] Therefore, this invention addresses the above problems by designing a bidirectional slip-type single-flow sealing well bottom limiting device. Summary of the Invention

[0004] The purpose of this invention is to provide a bidirectional slip-type single-flow sealing downhole limiting device, which solves the problems that existing single-flow downhole limiting locking devices cannot be used with tubing without couplings and are difficult to retrieve due to liquid accumulation above.

[0005] The technical solution adopted in this invention is a bidirectional slip-type single-flow sealing downhole limiting device, including a mandrel. One end of the mandrel is connected to a one-way sealing mechanism, and the other end of the mandrel is connected to a sand-prevention mechanism. A retrieval head is sleeved on the outer wall of the mandrel near the one-way sealing mechanism. A sliding sleeve is connected to the end of the retrieval head near the one-way sealing mechanism, and a locking sleeve is connected to the end of the retrieval head away from the one-way sealing mechanism. A locking and unlocking mechanism is provided between the locking sleeve and the mandrel. Several through grooves are equally spaced on the outer wall of the end of the locking sleeve away from the locking and unlocking mechanism. A locking mechanism is provided in each through groove and on the outer wall of the mandrel. A rubber sleeve mechanism is provided between the locking mechanism and the sand-prevention mechanism and on the outer wall of the mandrel.

[0006] The invention is further characterized in that,

[0007] The one-way sealing mechanism includes an upper core rod, one end of which is connected to the end of a spindle, and the other end of which is connected to a dispensing head via a cylindrical pin. A valve core is installed inside the upper core rod, one end of which contacts the dispensing head, and the other end of which is connected to one end of a one-way spring. A valve seat is installed at the other end of the one-way spring, one end of which is sleeved with the inner wall of the upper core rod, and the other end of which is sleeved with the inner wall of the spindle. A one-way ball is installed between the one-way spring and the valve seat.

[0008] The sand control mechanism includes a primary sand control cover, one end of which is connected to the spindle, the other end of which is connected to one end of a secondary sand control cover, and the other end of which is connected to the guide head.

[0009] The locking and unlocking mechanism includes an unlocking sleeve, which is connected to the spindle via unlocking shear pins. A locking ring seat is provided between the unlocking sleeve and the locking sleeve. A retaining ring is provided between the locking ring seat and the spindle. A backstop ring is provided between the unlocking sleeve and the spindle and near the retrieval head. A locking ring is provided between the unlocking sleeve and the spindle and near the retaining ring.

[0010] Each locking mechanism includes a slip and a cone. The slip is located in the through groove and on the outer wall of the mandrel. The cone is located between the locking sleeve and the mandrel. The conical surface of the cone contacts the end of the slip away from the locking stop and the unlocking mechanism. The end of the cone away from the slip is located outside the locking sleeve.

[0011] Both ends of the slip are beveled, and the end faces of the through groove that contact the two ends of the slip are also beveled. The two end faces of the through groove fit with the two end faces of the slip.

[0012] The cone is equipped with a locking block, which engages with the end of the locking sleeve.

[0013] An anti-rotation pin is provided inside the lock sleeve and between two adjacent slips. The anti-rotation pin is located on the outer wall of the spindle.

[0014] The rubber sleeve mechanism includes an upper rubber sleeve seat disposed on the outer wall of the mandrel. One end of the upper rubber sleeve seat is disposed between the cone and the mandrel, and rubber sleeve I, rubber sleeve II, and rubber sleeve I are sequentially disposed between the other end of the upper rubber sleeve seat and the sand-proof mechanism.

[0015] Hole I is provided on the side wall of the retrieval head, corresponding to the sliding sleeve, and hole II is provided on the side wall of the end of the mandrel near the one-way sealing mechanism.

[0016] The beneficial effects of this invention are:

[0017] (1) The bidirectional slip-type single-flow sealing well limit device of the present invention can realize the function of lifting seat seal locking by setting a locking mechanism;

[0018] (2) The bidirectional slip-type single-flow sealing downhole limiting device of the present invention forms a seal by setting a one-way sealing mechanism and a rubber sleeve mechanism to prevent the liquid column from falling back to the bottom of the well.

[0019] (3) The bidirectional slip-type single-flow sealing downhole limiting device of the present invention is equipped with a sliding sleeve. When it is necessary to retrieve the limiting device of the present invention, the sliding sleeve can be opened first to remove the liquid column at the top of the limiting device, so as to ensure that the retrieval tool can successfully grab the limiting device to carry out retrieval.

[0020] (4) The bidirectional slip-type single-flow sealing well bottom limit device of the present invention is equipped with two-stage sand protection covers, which can ensure sufficient flow channels while preventing sand particles from entering the wellbore from the bottom of the well and damaging the surface equipment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the bidirectional slip-type single-flow sealing downhole limiting device of the present invention;

[0022] Figure 2 This is a partial enlarged view of point A in the bidirectional slip-type single-flow sealing downhole limiting device of the present invention;

[0023] Figure 3 This is a schematic diagram illustrating the deployment process of the bidirectional slip-type single-flow sealing downhole limiting device of the present invention;

[0024] Figure 4 This is a schematic diagram of the bidirectional slip-type single-flow sealing downhole limiting device of the present invention, showing the opening of the sliding sleeve to relieve pressure.

[0025] Figure 5 This is a schematic diagram of the sealing of the channel before the sliding sleeve opens in the bidirectional slip-type single-flow sealing downhole limiting device of the present invention;

[0026] Figure 6 This is a schematic diagram showing the opening of the channel after the sliding sleeve is opened in the bidirectional slip-type single-flow sealing well bottom limiting device of the present invention.

[0027] In the diagram, 1. Drop head, 2. Cylindrical pin, 3. Upper core rod, 4. Single-flow ball, 5. Sliding sleeve, 6. Retrieval head, 7. Set screw I, 8. Snap ring, 9. Locking ring seat, 10. Retaining ring, 11. Slip, 12. Upper rubber sleeve seat, 13. Rubber sleeve I, 14. Rubber sleeve II, 15. Primary sandproof cover, 16. Socket head screw, 17. Set screw II, 18. Secondary sandproof cover, 19. Guide head, 20. Valve core, 21. Single-flow spring, 22. Valve seat, 23. Locking sleeve, 24. Anti-reverse ring, 25. Unsealing sleeve, 26. Unsealing shear pin, 27. Mandrel, 28. Anti-rotation pin, 29. Cone, 30. Locking block, 31. Hole I, 32. Hole II, 33. Through groove. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] This invention provides a bidirectional slip-type single-flow sealing downhole limiting device, the structure of which is as follows: Figure 1 As shown, the device includes a mandrel 27. One end of the mandrel 27 is connected to a one-way sealing mechanism, which forms a seal to prevent the liquid column from falling back to the bottom of the well. A hole II32 is provided on the side wall of the end of the mandrel 27 near the one-way sealing mechanism. The other end of the mandrel 27 is connected to a sand-prevention mechanism, which ensures sufficient flow passage while preventing sand particles from entering the wellbore and damaging surface equipment from the bottom of the well. A retrieval head 6 is fitted onto the outer wall of the mandrel 27 near the one-way sealing mechanism. A sliding sleeve 5 is connected to the end of the retrieval head 6 near the one-way sealing mechanism. A hole I31 is provided on the side wall of the retrieval head 6, corresponding to the sliding sleeve 5. O-rings are fitted between the retrieval head 6 and the sliding sleeve 5, on both sides of the hole I31. The mandrel 27 and the retrieval head 6... O-rings are provided on both sides of holes I31 and II32. The end of the retrieval head 6 away from the sliding sleeve 5 is connected to the mandrel 27 through the set screw I7. A locking sleeve 23 is connected to the outer wall of the retrieval head 6. An O-ring is provided between the locking sleeve 23 and the retrieval head 6. A locking and unsealing mechanism is provided between the locking sleeve 23 and the mandrel 27. Several through grooves are provided at equal intervals on the outer wall of the end of the locking sleeve 23 away from the locking and unsealing mechanism. A locking mechanism is provided in each through groove and on the outer wall of the mandrel 27. The locking mechanism can realize the locking of the lifting seat seal. A rubber sleeve mechanism is provided between the locking mechanism and the sand prevention mechanism and on the outer wall of the mandrel 27. The rubber sleeve mechanism can ensure sufficient flow channel while preventing sand particles from entering the wellbore from the bottom of the well and damaging the surface equipment.

[0030] Example 1

[0031] The one-way sealing mechanism includes an upper core rod 3, one end of which is connected to the end of a spindle 27, and the other end of which is connected to a dispensing head 1 via a cylindrical pin 2. A valve core 20 is provided inside the upper core rod 3, one end of which is in contact with the dispensing head 1, and the other end of which is connected to one end of a one-way spring 21. A valve seat 22 is provided at the other end of the one-way spring 21, one end of which is sleeved with the inner wall of the upper core rod 3, and the other end of which is sleeved with the inner wall of the spindle 27. A one-way ball 4 is provided between the one-way spring 21 and the valve seat 22, and an O-ring is provided between the valve seat 22 and the spindle 27.

[0032] Example 2

[0033] Based on Embodiment 1, the sand-proof mechanism includes a primary sand-proof cover 15. One end of the primary sand-proof cover 15 is connected to the spindle 27 via an internal hexagonal head screw 16. The other end of the primary sand-proof cover 15 is connected to one end of a secondary sand-proof cover 18. The other end of the secondary sand-proof cover 18 is connected to the guide head 19. There are two secondary sand-proof covers 18, and the two secondary sand-proof covers 18 are connected by set screws II17.

[0034] Example 3

[0035] Based on Example 2, the structure is as follows Figure 2 As shown, the locking and unlocking mechanism includes an unlocking sleeve 25, which is connected to the spindle 27 via an unlocking shear pin 26. A locking ring seat 9 is provided between the unlocking sleeve 25 and the locking sleeve 23. A retaining ring 10 is provided between the locking ring seat 9 and the spindle 27. A backstop ring 24 is provided between the unlocking sleeve 25 and the spindle 27 and near the end of the retrieval head 6. An O-ring is fitted on the outer wall of the backstop ring 24. A retaining ring 8 is provided between the unlocking sleeve 25 and the spindle 27 and near the end of the retaining ring 10.

[0036] Example 4

[0037] Based on embodiment 3, each locking mechanism includes a slip 11 and a cone 29. The outer wall of the slip 11 is provided with bidirectional setting teeth. After setting and positioning, it can withstand a bidirectional pressure load of not less than 10MPa from the upper and lower parts of the limiting device. The slip 11 is set in the through groove and on the outer wall of the spindle 27. The cone 29 is set between the locking sleeve 23 and the spindle 27. The conical surface of the cone 29 contacts the end of the slip 11 away from the locking stop and the unsealing mechanism. The end of the cone 29 away from the slip 11 is located outside the locking sleeve 23. Both ends of the slip 11 are beveled, and the end faces of the through groove that contact both ends of the slip 11 are also beveled. The two end faces of the through groove mate with the two end faces of the slip 11. A locking block 30 is provided on the cone 29. The locking block 30 engages with the end of the locking sleeve 23. An anti-rotation pin 28 is provided inside the locking sleeve 23 and between two adjacent slips 11. The anti-rotation pin 28 is provided on the outer wall of the spindle 27. An O-ring is provided between the anti-rotation pin 28 and the spindle 27.

[0038] The glue tube mechanism includes an upper glue tube seat 12 disposed on the outer wall of the mandrel 27. One end of the upper glue tube seat 12 is disposed between the cone 29 and the mandrel 27. The other end of the upper glue tube seat 12 and the sand-proof mechanism are sequentially provided with glue tube I 13, glue tube II 14, and glue tube I 13.

[0039] The working principle of the bidirectional slip-type single-flow sealing well bottom limiting device of the present invention is as follows:

[0040] (1) Deploy the bidirectional slip-type single-flow sealing well lower limit device of the present invention.

[0041] like Figure 3As shown, the bidirectional slip-type single-flow sealing downhole limiting device of the present invention completes the deployment process through wire rope operation. Before deployment, the deployment tool is connected to the deployment head 1. During deployment, the deployment tool is connected to the deployment tool string. When the deployment reaches the designated position, the wire rope string is suddenly stopped. Relying on the impact force of the limiting device of the present invention, the locking sleeve 23 has a downward movement, pushing the slip 11 to extend outward, so that the limiting device of the present invention is stuck on the oil pipe wall.

[0042] The wire rope trolley continues to apply force to lift the wire rope tool string, causing the delivery head 1 to move upward, which in turn drives the upper core rod 3, core shaft 27, cone 29, upper rubber tube seat 12, rubber tube I 13, rubber tube II 14, first-level sandproof cover 15, and second-level sandproof cover 18 to move upward, thus stabilizing the sealing force of the slip 11.

[0043] The wire rope operation vehicle continues to apply force to lift the wire rope tool string, causing the delivery head 1 to move upward, which in turn drives the upper core rod 3, core shaft 27, primary sandproof cover 15, and secondary sandproof cover 18 to move upward, compressing rubber cylinder I 16 and rubber cylinder II 17, so that the limiting device of the present invention and the pipe wall form a seal.

[0044] The wire rope trolley continues to apply force to lift the wire rope tool string until the cylindrical pin 2 is cut. Then, the delivery head 1 and the wire rope delivery tool are lifted out of the well shaft together, completing the delivery operation.

[0045] When the well is being opened for production, if the pressure at the bottom of the limiting device of the present invention is greater than the pressure at the top, the gas column and liquid column at the bottom of the well enter the limiting device of the present invention through the first-level sandproof cover 15 and the second-level sandproof cover 18, pushing the single flow ball 4 upward, so that the single flow ball 4 separates from the valve seat 22, thereby opening the channel, allowing the gas column and liquid column at the bottom of the well to be produced through the wellbore to the wellhead. At the same time, the first-level sandproof cover 15 and the second-level sandproof cover 18 effectively prevent sand particles at the bottom of the well from entering the wellbore.

[0046] When the well is shut off and energy is restored, the single-flow ball 4 relies on its own weight and the thrust of the single-flow spring 21 to form a downward one-way seal, closing the production channel, so that the falling liquid column gathers above the limiting device of the present invention and cannot fall back to the bottom of the well.

[0047] (2) The process of opening the sliding sleeve to release pressure in the bidirectional slip-type single-flow sealing well bottom limit device of the present invention

[0048] like Figure 4 , Figure 5 and Figure 6 As shown, the present invention completes the opening of the sliding sleeve through wire rope operation. When it is necessary to open the sliding sleeve 5 to release pressure, the wire rope operation tool string passes through the retrieval head 6 and pushes the sliding sleeve 5 downward, opening the inner and outer channels of the limiting device of the present invention, that is, the holes I31 and II32 are opened. The liquid column falls back to the bottom of the well by gravity through the holes I31 and II32.

[0049] (3) Retrieve the bidirectional slip-type single-flow sealing well bottom limit device of the present invention.

[0050] This invention achieves retrieval through wireline operations. The retrieval tool, connected to the well test wireline, is lowered to the position of the limiting device of this invention. After the retrieval tool aligns with the retrieval head 6, it is lifted. This part moves upward relative to the mandrel 27, slips 11, locking sleeve 23, rubber sleeve I 13, and rubber sleeve II 14 until the unsealing shear pin 26 is cut off. At this time, the retrieval head 6 is struck downward, causing the mandrel 27, primary sandproof cover 15, and secondary sandproof cover 18 to move downward. Simultaneously, rubber sleeve I 13, rubber sleeve II 14, and slips 11 retract, achieving unsealing. The wireline tool string is continuously lifted to retrieve the limiting device of this invention.

Claims

1. A bidirectional slip-type single-flow sealing downhole limiting device, characterized in that, Includes a mandrel (27), one end of which is connected to a one-way sealing mechanism, and the other end of which is connected to a sand-proof mechanism. A retrieval head (6) is sleeved on the outer wall of the mandrel (27) near the one-way sealing mechanism. A sliding sleeve (5) is connected to the end of the retrieval head (6) near the one-way sealing mechanism. A locking sleeve (23) is connected to the end of the retrieval head (6) away from the one-way sealing mechanism. A blocking and unsealing mechanism is provided between the locking sleeve (23) and the mandrel (27). Several through grooves (33) are provided at equal intervals on the outer wall of the end of the locking sleeve (23) away from the blocking and unsealing mechanism. A locking mechanism is provided in each through groove (33) and on the outer wall of the mandrel (27). A rubber sleeve mechanism is provided between the locking mechanism and the sand-proof mechanism and on the outer wall of the mandrel (27). The locking and unlocking mechanism includes an unlocking sleeve (25), which is connected to the spindle (27) via an unlocking shear pin (26). A locking ring seat (9) is provided between the unlocking sleeve (25) and the locking sleeve (23). A retaining ring (10) is provided between the locking ring seat (9) and the spindle (27). A backstop ring (24) is provided between the unlocking sleeve (25) and the spindle (27) and near the end of the retrieval head (6). A retaining ring (8) is provided between the unlocking sleeve (25) and the spindle (27) and near the end of the retaining ring (10). Each of the locking mechanisms includes a slip (11) and a cone (29). The slip (11) is disposed in the through groove (33) and on the outer wall of the spindle (27). The cone (29) is disposed between the locking sleeve (23) and the spindle (27). The conical surface of the cone (29) contacts the end of the slip (11) away from the locking and unlocking mechanism. The end of the cone (29) away from the slip (11) is located outside the locking sleeve (23). A locking block (30) is provided on the cone (29), and the locking block (30) is engaged with the end of the locking sleeve (23).

2. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, The one-way sealing mechanism includes an upper core rod (3), one end of which is connected to the end of the spindle (27), and the other end of which is connected to the dispensing head (1) via a cylindrical pin (2). A valve core (20) is provided inside the upper core rod (3), one end of which is in contact with the dispensing head (1), and the other end of which is connected to one end of a single-flow spring (21). A valve seat (22) is provided at the other end of the single-flow spring (21), one end of which is sleeved with the inner wall of the upper core rod (3), and the other end of which is sleeved with the inner wall of the spindle (27). A single-flow ball (4) is provided between the single-flow spring (21) and the valve seat (22).

3. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, The sand-proof mechanism includes a primary sand-proof cover (15), one end of which is connected to a spindle (27), the other end of which is connected to one end of a secondary sand-proof cover (18), and the other end of which is connected to a guide head (19).

4. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, Both ends of the slip (11) are set as inclined surfaces, and the end faces of the through groove (33) that contact the two ends of the slip (11) are set as inclined surfaces. The two end faces of the through groove (33) are matched with the two end faces of the slip (11).

5. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, An anti-rotation pin (28) is provided inside the lock sleeve (23) and between two adjacent slips (11), and the anti-rotation pin (28) is provided on the outer wall of the spindle (27).

6. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, The glue tube mechanism includes an upper glue tube seat (12) disposed on the outer wall of the mandrel (27). One end of the upper glue tube seat (12) is disposed between the cone (29) and the mandrel (27). The other end of the upper glue tube seat (12) is disposed between the sand-proof mechanism and glue tube I (13), glue tube II (14), and glue tube I (13).

7. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that, The retrieval head (6) has a hole I (31) on its side wall, which is corresponding to the sliding sleeve (5), and the spindle (27) has a hole II (32) on its side wall near the one-way sealing mechanism.

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