Two-way slip type uniflow sealing well lower limiting device

Abstract

The invention discloses a two-way slip type uniflow sealing underground limiting device which comprises a mandrel, one end of the mandrel is connected with a one-way sealing mechanism, the other end of the mandrel is connected with a sand prevention mechanism, the end, close to the one-way sealing mechanism, of the outer wall of the mandrel is sleeved with a fishing head, and the end, close to the one-way sealing mechanism, of the fishing head is connected with a sliding sleeve. The end, away from the one-way sealing mechanism, of the fishing head is connected with a lock sleeve, a blocking and unblocking mechanism is arranged between the lock sleeve and the mandrel, a plurality of through grooves (33) are formed in the outer wall of the end, away from the blocking and unblocking mechanism, of the lock sleeve at equal intervals, and a clamping mechanism is arranged in each through groove (33) and located on the outer wall of the mandrel. A rubber sleeve mechanism is arranged between the clamping mechanism and the sand prevention mechanism and located on the outer wall of the mandrel. The limiting device solves the problems that an existing uniflow well lower limiting clamping device cannot be suitable for a non-coupling oil pipe, and fishing is not easy due to the fact that liquid is accumulated on the upper portion.

Description

Technical Field

[0001] The invention belongs to the technical field of downhole limit devices, and in particular relates to a bidirectional slip-type single-flow sealing downhole limit device. Background Art

[0002] The plunger gas lift drainage and gas production process has become an important drainage technology for gas fields, with the advantages of high intelligence, high drainage efficiency, long action time, and low cost. For conventional plungers, downhole limit stoppers need to be installed. Downhole limit stoppers are divided into two types according to the fluid permeability: non-single-flow type and single-flow limit function. Due to the non-single-flow type of downhole limit stoppers, during the operation of the plunger, the liquid falls back to the bottom of the well, increasing the bottom hole back pressure, which will lead to a decrease in plunger efficiency. Therefore, downhole limit stoppers with single-flow limit function are currently used. They have a single-flow effect while locking, and the liquid falls above the stopper, reducing the bottom hole back pressure, thereby improving the drainage efficiency of the plunger. However, it adopts a bullet-type locking device, and the locking mechanism needs to be locked into the oil pipe coupling, so that it can only be used for coupling oil pipes (EUE oil pipes) and cannot be used for uncoupled oil pipes (FOX oil pipes). At the same time, when salvage is required, the liquid accumulated above the downhole limit clamp with a single-flow limiting function is large, resulting in an increase in the working tension and an inability to produce displacement and unsealing normally, which brings great difficulties to salvage.

[0003] Therefore, the present invention designs a bidirectional slip-type single-flow sealing downhole limiting device to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a bidirectional slip-type single-flow sealing downhole limit device to solve the problem that the existing single-flow downhole limit fixture cannot be applied to the uncoupled oil pipe and is difficult to salvage due to the accumulated liquid on the top.

[0005] The technical solution adopted by the present invention is a two-way slip-type single-flow sealing downhole limit device, comprising a core shaft, one end of the core shaft is connected to a one-way sealing mechanism, the other end of the core shaft is connected to a sand control mechanism, a fishing head is sleeved on the outer wall of the core shaft at one end close to the one-way sealing mechanism, the end of the fishing head close to the one-way sealing mechanism is connected to a sliding sleeve, the end of the fishing head away from the one-way sealing mechanism is connected to a locking sleeve, a blocking and unsealing mechanism is arranged between the locking sleeve and the core shaft, a plurality of through grooves are arranged at equal intervals on the outer wall of the end of the locking sleeve away from the blocking and unsealing mechanism, a locking mechanism is arranged in each of the through grooves and on the outer wall of the core shaft, and a rubber sleeve mechanism is arranged between the locking mechanism and the sand control mechanism and on the outer wall of the core shaft.

[0006] The present invention is also characterized in that:

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

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

[0009] The blocking and unsealing mechanism includes an unsealing sleeve, which is connected to the core shaft through unsealing shear pins, a locking ring seat is arranged between the unsealing sleeve and the locking sleeve, a retaining ring is arranged between the locking ring seat and the core shaft, a stop ring is arranged between the unsealing sleeve and the core shaft and at one end close to the salvaging head, and a clamping ring is arranged between the unsealing sleeve and the core shaft and at one end close to the retaining ring.

[0010] Each locking mechanism includes a slip and a cone. The slip is arranged in the through groove and on the outer wall of the core shaft. The cone is arranged between the locking sleeve and the core shaft. The conical surface of the cone contacts the end of the slip away from the blocking and unblocking mechanism, and the end of the cone away from the slip is located outside the locking sleeve.

[0011] Both ends of the slip are arranged as inclined surfaces, the end surfaces of the through groove contacting the two ends of the slip are arranged as inclined surfaces, and the two end surfaces of the through groove are matched with the two end surfaces of the slip.

[0012] A clamping block is arranged on the cone, and the clamping block is clamped with the end of the locking sleeve.

[0013] A rotation-stopping pin is arranged in the lock sleeve and between two adjacent slips, and the rotation-stopping pin is arranged on the outer wall of the core shaft.

[0014] The rubber cylinder mechanism comprises a rubber cylinder seat arranged on the outer wall of the core shaft, one end of the rubber cylinder seat is arranged between the cone and the core shaft, and rubber cylinders I, II and I are arranged in sequence between the other end of the rubber cylinder seat and the sand prevention mechanism.

[0015] A hole I is arranged on the side wall of the fishing head at a position corresponding to the sliding sleeve, and a hole II is arranged on the side wall of one end of the core shaft close to the one-way sealing mechanism.

[0016] The beneficial effects of the present invention are:

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

[0018] (2) The bidirectional slip-type single-flow sealing downhole limit device of the present invention forms a seal by providing 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 limit device of the present invention is provided with a sliding sleeve. When the limit device of the present invention needs to be salvaged, the sliding sleeve can be opened first to remove the liquid column on the upper part of the limit device to ensure that the salvage tool can smoothly grasp the limit device to carry out salvage;

[0020] (4) The bidirectional slip-type single-flow sealing downhole limit device of the present invention is provided with a two-stage sand-proof cover to ensure sufficient flow passage while preventing sand from entering the wellbore and the ground from the bottom of the well to damage the ground equipment. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0024] Figure 4 It is a schematic diagram of the bidirectional slip-type single-flow sealing downhole limit device of the present invention opening the sleeve to relieve pressure;

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

[0026] Figure 6 It is a schematic diagram of the opening of the channel after the sleeve is opened in the bidirectional slip-type single-flow sealing downhole limit device of the present invention.

[0027] In the figure, 1. launching head, 2. cylindrical pin, 3. upper core rod, 4. single flow ball, 5. sliding sleeve, 6. fishing head, 7. set screw I, 8. retaining ring, 9. locking ring seat, 10. retaining ring, 11. slip, 12. upper rubber cylinder seat, 13. rubber cylinder I, 14. rubber cylinder II, 15. primary sand cover, 16. hexagon socket head screw, 17. set screw II, 18. secondary sand cover, 19. guide head, 20. valve core, 21. single flow spring, 22. valve seat, 23. locking sleeve, 24. check ring, 25. unsealing sleeve, 26. unsealing shear nail, 27. core shaft, 28. anti-rotation pin, 29. cone, 30. block, 31. hole I, 32. hole II, 33. through groove. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention provides a bidirectional slip-type single-flow sealing downhole limit device, the structure of which is as follows: Figure 1 As shown, it includes a core shaft 27, one end of which is connected to a one-way sealing mechanism, which is used to form a seal to prevent the liquid column from falling back to the bottom of the well. A hole II32 is arranged on the side wall of the end of the core shaft 27 close to the one-way sealing mechanism, and the other end of the core shaft 27 is connected to a sand prevention mechanism, which can ensure sufficient flow channels while preventing sand from entering the wellbore and the ground from the bottom of the well to damage ground equipment. A salvage head 6 is sleeved on the end of the outer wall of the core shaft 27 close to the one-way sealing mechanism, and a sliding sleeve 5 is connected to the end of the salvage head 6 close to the one-way sealing mechanism. A hole I31 is arranged on the side wall of the salvage head 6 and at a position corresponding to the sliding sleeve 5. O-rings are sleeved between the salvage head 6 and the sliding sleeve 5 and on both sides of the hole I31, and the core shaft 27 and the salvage head 6 are connected. An O-ring is arranged between and on both sides of the hole I31 and the hole II32. The end of the salvage head 6 away from the sliding sleeve 5 is connected to the core shaft 27 through a set screw I7. A locking sleeve 23 is connected to the outer wall of the salvage head 6. An O-ring is arranged between the locking sleeve 23 and the salvage head 6. A blocking and unsealing mechanism is arranged between the locking sleeve 23 and the core shaft 27. A plurality of through grooves are arranged 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 arranged in each through groove and on the outer wall of the core shaft 27. The locking mechanism can realize the lifting seat sealing and locking. A rubber tube mechanism is arranged between the locking mechanism and the sand prevention mechanism and on the outer wall of the core shaft 27. The rubber tube mechanism can ensure sufficient flow passage while preventing sand from entering the wellbore and the ground from the bottom of the well to damage the ground 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 the core shaft 27, and the other end of the upper core rod 3 is connected to the delivery head 1 through a cylindrical pin 2. A valve core 20 is arranged inside the upper core rod 3, one end of the valve core 20 contacts the delivery head 1, and the other end of the valve core 20 is connected to one end of a single-flow spring 21. A valve seat 22 is arranged at the other end of the single-flow spring 21, one end of the valve seat 22 is sleeved with the inner wall of the upper core rod 3, and the other end of the valve seat 22 is sleeved with the inner wall of the core shaft 27, a single-flow ball 4 is arranged between the single-flow spring 21 and the valve seat 22, and an O-ring is arranged between the valve seat 22 and the core shaft 27.

[0032] Example 2

[0033] On the basis of Example 1, the sand prevention mechanism includes a first-level sand prevention cover 15, one end of the first-level sand prevention cover 15 is connected to the core shaft 27 through a hexagon socket head screw 16, the other end of the first-level sand prevention cover 15 is connected to one end of a second-level sand prevention cover 18, the other end of the second-level sand prevention cover 18 is connected to a guide head 19, there are two second-level sand prevention covers 18, and the two second-level sand prevention covers 18 are connected by a set screw II17.

[0034] Example 3

[0035] Based on Example 2, the structure is as follows Figure 2 As shown, the blocking and unsealing mechanism includes an unsealing sleeve 25, which is connected to the core shaft 27 through an unsealing shear nail 26, a locking ring seat 9 is arranged between the unsealing sleeve 25 and the locking sleeve 23, a retaining ring 10 is arranged between the locking ring seat 9 and the core shaft 27, a stop ring 24 is arranged between the unsealing sleeve 25 and the core shaft 27 and at one end close to the salvage head 6, an O-ring is sleeved on the outer wall of the stop ring 24, and a clamping ring 8 is arranged between the unsealing sleeve 25 and the core shaft 27 and at one end close to the retaining ring 10.

[0036] Example 4

[0037] On the basis of Example 3, each locking mechanism includes a cava 11 and a cone 29. A bidirectional sealing tooth is provided on the outer wall of the cava 11. After the sealing is positioned, it can withstand the bidirectional pressure load of not less than 10 MPa on the upper and lower parts of the limiting device. The cava 11 is arranged in the through groove and on the outer wall of the core shaft 27. The cone 29 is arranged between the locking sleeve 23 and the core shaft 27. The conical surface of the cone 29 contacts the end of the cava 11 away from the blocking and unsealing mechanism, and the end of the cone 29 away from the cava 11 is located outside the locking sleeve 23. Both ends of the slip 11 are set as inclined surfaces, and the end surfaces of the through groove contacting the two ends of the slip 11 are set as inclined surfaces. The two end surfaces of the through groove cooperate with the two end surfaces of the slip 11. A clamping block 30 is set on the cone 29, and the clamping block 30 is clamped with the end of the locking sleeve 23. A stop pin 28 is set in the locking sleeve 23 and between two adjacent slips 11. The stop pin 28 is set on the outer wall of the core shaft 27, and an O-ring is set between the stop pin 28 and the core shaft 27.

[0038] The rubber cylinder mechanism includes a rubber cylinder seat 12 arranged on the outer wall of the core shaft 27, one end of the rubber cylinder seat 12 is arranged between the cone 29 and the core shaft 27, and rubber cylinder I 13, rubber cylinder II 14, and rubber cylinder I 13 are arranged in sequence between the other end of the rubber cylinder seat 12 and the sand prevention mechanism.

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

[0040] (1) Deployment of the bidirectional slip-type single-flow sealing downhole limit device of the present invention

[0041] like Figure 3As shown, the bidirectional slip-type single-flow sealing downhole limit device of the present invention completes the delivery process through wire operation. Before delivery, the delivery tool is connected to the delivery head 1. When delivering, the delivery tool is connected with the wire tool string. When delivered to the specified position, the wire tool string is stopped suddenly. Relying on the impact force of the limit device of the present invention itself, the locking sleeve 23 has the action of continuing to go down, pushing the slip 11 to extend outward, so that the limit device seat of the present invention is stuck on the wall of the oil pipe;

[0042] The wireline operation vehicle continues to apply force to lift the wireline tool string, so that the delivery head 1 moves upward, driving the upper core rod 3, the core shaft 27, the cone 29, the upper rubber cylinder seat 12, the rubber cylinder I 13, the rubber cylinder II 14, the first-level sand control cover 15, and the second-level sand control cover 18 upward to stabilize the sealing force of the slip 11;

[0043] The wireline operation vehicle continues to apply force to lift the wireline tool string, so that the delivery head 1 moves upward, driving the upper core rod 3, the core shaft 27, the first-level sand control cover 15, and the second-level sand control cover 18 upward, compressing the rubber cylinder I 16 and the rubber cylinder II 17, so that the limit device of the present invention and the pipe wall form a seal;

[0044] The wireline operation vehicle continues to apply force to lift the wireline tool string until the cylindrical pin 2 is cut off, and then the delivery head 1 and the wireline operation delivery tool are lifted out of the wellbore together to complete the delivery operation.

[0045] When the well is opened for production, when the lower pressure of the position limiting device of the present invention is greater than the upper pressure, the gas column and liquid column at the bottom of the well enter the interior of the position limiting device of the present invention through the primary sand control cover 15 and the secondary sand control cover 18, and push the single flow ball 4 upward to separate the single flow ball 4 from the valve seat 22, thereby opening the channel, so that the gas column and liquid column at the bottom of the well are produced to the wellhead through the wellbore, and at the same time, the primary sand control cover 15 and the secondary sand control cover 18 effectively prevent sand at the bottom of the well from entering the wellbore;

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

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

[0048] like Figure 4 , Figure 5 and Figure 6 As shown, the present invention completes the opening of the sleeve through wire operation. When the sleeve 5 needs to be opened to release pressure, the wire operation tool string passes through the fishing head 6, pushes the sleeve 5 downward, opens the inner and outer channels of the limit device of the present invention, that is, the hole I31 and the hole II32 are opened, and the liquid column falls back to the bottom of the well through the hole I31 and the hole II32 by gravity.

[0049] (3) Salvage of the bidirectional slip-type single-flow sealing downhole limit device of the present invention

[0050] The present invention completes salvage through wire operation. The well test wire is connected to the salvage tool and lowered into the position of the limit device of the present invention. When the salvage tool is docked with the salvage head 6 and then lifted up, the part moves up relatively with respect to the mandrel 27, the slip 11, the locking sleeve 23, the rubber cylinder I 13 and the rubber cylinder II 14 until the unsealing shear nail 26 is cut off. At this time, the salvage head 6 is struck downward to move the mandrel 27, the primary sand cover 15 and the secondary sand cover 18 downward. At the same time, the rubber cylinder I 13, the rubber cylinder II 14 and the slip 11 are contracted to achieve unsealing. The wire tool string is continuously lifted up to salvage the limit device of the present invention.

Claims

1. A two-way slip-type single-flow sealing downhole limit device, characterized in that: The invention comprises a core shaft (27), one end of the core shaft (27) is connected to a one-way sealing mechanism, the other end of the core shaft (27) is connected to a sand prevention mechanism, a fishing head (6) is sleeved on the end of the outer wall of the core shaft (27) close to the one-way sealing mechanism, the end of the fishing head (6) close to the one-way sealing mechanism is connected to a sliding sleeve (5), the end of the fishing head (6) away from the one-way sealing mechanism is connected to a locking sleeve (23), a blocking and unsealing mechanism is arranged between the locking sleeve (23) and the core shaft (27), a plurality of through grooves (33) are arranged 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 arranged in each of the through grooves (33) and on the outer wall of the core shaft (27), and a rubber sleeve mechanism is arranged between the locking mechanism and the sand prevention mechanism and on the outer wall of the core shaft (27).

2. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1 is characterized in that: The one-way sealing mechanism comprises an upper core rod (3), one end of which is connected to the end of a core shaft (27), and the other end of which is connected to a delivery head (1) via a cylindrical pin (2). A valve core (20) is arranged inside the upper core rod (3), one end of which is in contact with the delivery head (1), and the other end of which is connected to one end of a single-flow spring (21). A valve seat (22) is arranged 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 core shaft (27). A single-flow ball (4) is arranged 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 is characterized in that: The sand control mechanism comprises a primary sand control cover (15), one end of the primary sand control cover (15) is connected to the core shaft (27), the other end of the primary sand control cover (15) is connected to one end of the secondary sand control cover (18), and the other end of the secondary sand control cover (18) is connected to the guide head (19).

4. The bidirectional slip-type single-flow sealing downhole limit device according to claim 1 is characterized in that: The blocking and unsealing mechanism comprises an unsealing sleeve (25), the unsealing sleeve (25) being connected to a core shaft (27) via an unsealing shear pin (26), a locking ring seat (9) being arranged between the unsealing sleeve (25) and the locking sleeve (23), a retaining ring (10) being arranged between the locking ring seat (9) and the core shaft (27), a stop ring (24) being arranged between the unsealing sleeve (25) and the core shaft (27) and at one end close to the fishing head (6), and a clamping ring (8) being arranged between the unsealing sleeve (25) and the core shaft (27) and at one end close to the retaining ring (10).

5. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1 is characterized in that: Each of the locking mechanisms comprises a slip (11) and a cone (29); the slip (11) is arranged in the through groove (33) and on the outer wall of the core shaft (27); the cone (29) is arranged between the locking sleeve (23) and the core shaft (27); the cone surface of the cone (29) contacts with an end of the slip (11) away from the blocking and unblocking mechanism; and the end of the cone (29) away from the slip (11) is located outside the locking sleeve (23).

6. The bidirectional slip-type single-flow sealing downhole limit device according to claim 5 is characterized in that: Both ends of the slip (11) are arranged as inclined surfaces, the end surfaces of the through groove (33) contacting the two ends of the slip (11) are arranged as inclined surfaces, and the two end surfaces of the through groove (33) match the two end surfaces of the slip (11).

7. The bidirectional slip-type single-flow sealing downhole limit device according to claim 5 is characterized in that: A clamping block (30) is provided on the cone (29), and the clamping block (30) is clamped with the end of the locking sleeve (23).

8. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 5 is characterized in that: A stop pin (28) is arranged inside the lock sleeve (23) and between two adjacent slips (11), and the stop pin (28) is arranged on the outer wall of the core shaft (27).

9. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 5 is characterized in that: The rubber cylinder mechanism comprises a rubber cylinder seat (12) arranged on the outer wall of the core shaft (27), one end of the rubber cylinder seat (12) is arranged between the cone (29) and the core shaft (27), and rubber cylinder I (13), rubber cylinder II (14), and rubber cylinder I (13) are arranged in sequence between the other end of the rubber cylinder seat (12) and the sand prevention mechanism.

10. The bidirectional slip-type single-flow sealing downhole limiting device according to claim 1, characterized in that: A hole I (31) is provided on the side wall of the fishing head (6) at a position corresponding to the sliding sleeve (5), and a hole II (32) is provided on the side wall of one end of the core shaft (27) close to the one-way sealing mechanism.

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