Setting adapter, ball seat assembly and fracturing ball recovery method

Abstract

The invention relates to the technical field of downhole tools, in particular to a setting adapter, a ball seat assembly and a fracturing ball recovery method. A setting adapter comprises a push cylinder and a release lever. The push cylinder is provided with a ball seat abutting section, the ball seat abutting section is used for being connected with a ball seat in an abutting mode, and the passing direction of the one-way passing mechanism is the direction extending from the axial outer side of the ball seat abutting section to the inner side of the ball seat abutting section. And after the ball seat finishes setting, the releasing lever retreats into the push cylinder, and a first space for accommodating the fracturing ball is formed among the end part of the releasing lever, the abutting section of the ball seat and the one-way passing mechanism. When the fracturing balls need to be recycled, the fracturing balls are flowback and pushed into the first space in the pushing cylinder in a flowback mode, the fracturing balls are prevented from falling off from the pushing cylinder through a one-way passing mechanism, and the recycling reliability of the fracturing balls is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole tools, and in particular to a setting adapter, a ball seat assembly and a fracturing ball recovery method. Background Art

[0002] Existing fracturing mostly adopts perforation-connected fracturing. In order to save pumping fracturing balls and save water, a ball seat with a pre-set ball will be used, but there are two risks. First, after the ball seat is sealed, if the seal is not tight during the seal inspection, a new ball seat needs to be put in again. At this time, the second ball seat needs to be pumped for the second time, but at this time, there is no channel for pumping fluid in the wellbore, and the secondary pumping cannot be achieved; the second risk is that the perforation gun fails to ignite and the perforating gun needs to be pumped again for the second time. There will also be no channel for pumping fluid in the wellbore, and the purpose of secondary pumping cannot be achieved; to achieve the purpose of secondary pumping, the fracturing balls need to be captured and recovered. The existing method of capturing and recovering fracturing balls is through a special ball-collecting adapter or a fracturing ball recovery device. This method of capturing and recovering fracturing balls using separate equipment is relatively complicated and costly. Summary of the invention

[0003] The present invention solves one of the problems in the prior art and provides a sealing adapter, a ball seat assembly and a sealing ring for a fracturing ball recovery method.

[0004] The technical solution is as follows:

[0005] A setting adapter comprises a push tube and a release lever;

[0006] The push cylinder has a ball seat abutment section, the ball seat abutment section is used to abut and connect with the ball seat, and a one-way passing mechanism for one-way passage of the fracturing ball is provided in the ball seat abutment section, and the passing direction of the one-way passing mechanism is a direction extending from the axial outer side of the ball seat abutment section to the inner side thereof;

[0007] The release lever has a ball seat connecting section, and the ball seat connecting section passes through the one-way passing mechanism for adapting and connecting with the ball seat. When the ball seat is sealed, the release lever retreats into the push cylinder, and a first space for accommodating the fracturing ball is defined between the end of the release lever, the ball seat abutting section and the one-way passing mechanism.

[0008] The working principle and beneficial effects of the present invention are as follows: by adopting the setting adapter of the present invention, after the setting is completed, the release lever is retracted into the push tube, and a first space for accommodating the fracturing ball is provided between the end of the release lever, the ball seat abutment section and the one-way passing mechanism; when a secondary pumping operation is required, the fracturing ball is pushed back into the first space in the push tube by backflow, and at the same time, the one-way passing mechanism limits the fracturing ball from falling off from the push tube, thereby ensuring the reliability of the recovery of the fracturing ball.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, the one-way passing mechanism is a single-layer mechanism, which is a spring layer, and the spring layer has multiple springs. The aperture formed by the ends of the multiple springs is smaller than the diameter of the fracturing ball, and the ends of the multiple springs extend obliquely away from the ball seat abutment section.

[0011] The beneficial effect of adopting the above further solution is that the single-layer structure in which the ends of the plurality of spring pieces extend obliquely in a direction away from the ball seat abutment section achieves a simple one-way restriction effect on the fracturing ball.

[0012] Based on the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the spring sheet has a first end and a second end, the first end is connected with the outer ring to form an integral structure, the outer ring is fixedly arranged on the ball seat abutment section, and the second end extends obliquely in a direction away from the ball seat abutment section.

[0014] The beneficial effect of adopting the above further solution is that the first end is arranged as an integral structure to facilitate the installation of the entire one-way passage mechanism.

[0015] Based on the above technical solution, the present invention can also be improved as follows.

[0016] Furthermore, the one-way passing mechanism is a double-layer mechanism, including a spring sheet layer and a retaining ring layer, the spring sheet layer has a plurality of spring sheets, the aperture formed by the ends of the plurality of spring sheets is smaller than the diameter of the fracturing ball, and the spring sheet layer is arranged on the axial inner side of the ball seat abutment section; the retaining ring layer has a through hole through which the fracturing ball passes, the through hole diameter is larger than the diameter of the fracturing ball, and the retaining ring layer is arranged on the axial outer side of the ball seat abutment section.

[0017] The beneficial effect of adopting the above further solution is: by setting a double-layer structure, the fracturing ball can pass through the direction extending from the axial outer side to the inner side of the ball seat abutment section, but cannot pass through in the opposite direction; at the same time, the retaining ring layer provides a reliable limiting effect.

[0018] Based on the above technical solution, the present invention can also be improved as follows.

[0019] Furthermore, the one-way passing mechanism is a variable diameter coil spring structure, the diameter of the middle hole of the variable diameter coil spring structure is smaller than the diameter of the fracturing ball, and the small end of the variable diameter coil spring extends obliquely in a direction away from the ball seat abutment section.

[0020] The beneficial effect of adopting the above further scheme is: the middle through hole is smaller than the fracturing ball, the fracturing ball enters the variable diameter coil spring structure from the ball seat abutment section, and when the impact force of the return flow on the fracturing ball is large, the aperture of the middle through hole becomes larger, and the fracturing ball smoothly passes through the variable diameter coil spring structure into the first space; due to the variable diameter coil spring structure, the fracturing ball will not fall off from the first space.

[0021] Based on the above technical solution, the present invention can also be improved as follows.

[0022] Furthermore, it also includes a second space for accommodating the fracturing ball. When the release rod passes through the one-way passing mechanism, the second space is formed between the ball seat abutment section and the release rod.

[0023] The beneficial effect of adopting the above further solution is that the second space formed in the ball seat abutment section in the push barrel is used to accommodate the fracturing ball, which facilitates pre-setting the fracturing ball in the push barrel.

[0024] Based on the above technical solution, the present invention can also be improved as follows.

[0025] Furthermore, an axial groove is provided on the ball seat abutment section between the one-way passing mechanism and the ball seat, and a second space for accommodating the fracturing ball is formed at the axial groove, and the axial groove is used to fix the one-way passing mechanism.

[0026] The beneficial effects of adopting the above further solution are: by providing the axial groove, the space for accommodating the fracturing ball is increased on the ball seat abutment section, which facilitates the placement of the fracturing ball; at the same time, the one-way passing mechanism can be fixed at the axial groove.

[0027] The present invention also provides a ball seat assembly, including a ball seat body and an adapter, wherein the adapter is the above-mentioned sealing adapter, and the ball seat body includes a center tube, a sealing anchoring structure and a lower joint, wherein the sealing anchoring structure is sleeved on the center tube, and the lower joint is located at an end away from the center tube and abuts against the sealing anchoring structure; the ball seat abutting section abuts against the center tube, and the ball seat connecting section is connected to the lower joint.

[0028] The beneficial effect of the ball seat assembly of the present invention is that by setting the above-mentioned ball seat assembly, after the seat is sealed, when the fracturing ball needs to be recovered, there is no need to invest in a special fracturing ball capture and recovery tool, and the fracturing ball can be recovered directly at the bottom of the well, which simplifies the process and saves costs.

[0029] Based on the above technical solution, the present invention can also be improved as follows.

[0030] Furthermore, the sealing anchoring structure includes a sealing ring and a slip assembly, the sealing ring includes a sealing body and a pumping body, the sealing body and the pumping body are an integral structure; the contact surface between the sealing body and the slip assembly is a slip contact surface, and the slip contact surface is an inclined surface, which is used to abut against the slip assembly and press the sealing body; the pumping body is an outwardly turnable skirt structure; the skirt structure is close to the end of the sealing body as the skirt bottom, and the skirt structure is a stepped multi-level structure with a thickness gradually increasing in the direction extending toward the skirt bottom; the skirt structure is provided with a plurality of openings in the circumference, and the plurality of openings are evenly distributed on the circumference of the skirt structure.

[0031] The beneficial effect of adopting the above further scheme is: the present invention sets the sealing body and the pumping body as an integrated structure, and the sealing ring is directly installed on the downhole isolation tool. When pumping, the skirt structure is turned outward and subjected to force, and the slip contact surface of the sealing body is an inclined surface, which is used to abut with the slip assembly and press the sealing body to ensure that the sealing ring will not fall off, thereby improving the reliability of pumping. After the pumping is completed, the sealing body can be used for the sealing effect of the isolation tool and the wellbore. At the same time, by setting a gradually thickening structure from top to bottom, when the pumping displacement is low, the thinner top is easy to turn outward, and can be turned outward quickly to generate pumping thrust, driving the entire downhole tool to be quickly lowered, so as to achieve the purpose of improving the pumping effect; as the pumping displacement increases, the skirt turns outward step by step, and the pumping thrust generated also increases step by step. In the actual pumping process, it will not cause an instantaneous sudden increase in cable tension, avoiding the risk of the cable being broken; in addition, the thicker bottom structure ensures that the skirt structure has sufficient pressure bearing capacity to achieve a reliable pumping effect. The stepped multi-stage structure has a better effect of opening step by step when the pumping displacement is low.

[0032] Based on the above technical solution, the present invention can also be improved as follows.

[0033] Furthermore, a flange protruding toward the slip assembly is provided on the sealing body at the point where it abuts against the slip assembly, and the flange is used to cover part of the slip assembly; a convex ring structure is provided on the inner surface of the sealing body, and the top of the convex ring structure extends toward the slip assembly.

[0034] The beneficial effect of adopting the above further scheme is: the flange structure is provided, and after the seal is set, part of the slip assembly plays a compressive support role on the flange, and plays a good auxiliary sealing role. At the same time, by providing a groove matching the convex ring structure on the central tube, before the seal is set, the convex ring structure is located in the groove, and during the pumping process, the convex ring structure is matched and connected with the groove, and the sealing pumping sealing ring will not fall off the central tube, further ensuring the reliability of the pumping; at the same time, when the seal is set, the convex ring structure is pressed against the outer wall of the central tube, which increases the thickness of the sealing body and improves the sealing reliability of the sealing body.

[0035] Based on the above technical solution, the present invention can also be improved as follows.

[0036] Furthermore, it also includes a pressure ring, which is arranged at the bottom of the skirt; or, the pressure ring is arranged on the circumference of the outer cylindrical surface between the sealing body and the pumping body.

[0037] The beneficial effect of adopting the above further solution is: a compression ring structure is provided, and the compression ring compresses the sealing ring against the downhole tool in the radial direction, further ensuring the reliability and stability of the sealing ring during the pumping process. At the same time, the position of the compression ring can be set outside or inside according to actual conditions.

[0038] The present invention also provides a fracturing ball recovery method, including using the above-mentioned setting adapter, and the specific steps include:

[0039] removing the release lever from the adapter;

[0040] At the section away from the ball seat abutment, the push cylinder is connected to the bottom of the pipe string connected to the oil or cable.

[0041] Lowering the push tube to a set position underground;

[0042] The return well fluid flushes the captured sphere into the first space, and the return well fluid stops;

[0043] The tubing string is lifted out of the wellbore and the captured ball is removed.

[0044] The beneficial effect of the fracturing ball recovery method of the present invention is that when the setting adapter of the present invention is used alone as a fracturing ball recovery device, the function of efficiently capturing balls can be achieved by only removing the release lever from the adapter.

[0045] The present invention also provides a fracturing ball recovery method, which includes using the above-mentioned ball seat assembly, and the specific steps include:

[0046] The ball seat assembly enters the preset position of the wellbore, the sealing tool starts to work, and the ball seat completes the sealing;

[0047] The setting tool continues to work, the release lever is retracted into the push cylinder, and a first space for accommodating the fracturing ball is formed between the ball seat connecting section and the one-way passing mechanism;

[0048] The pipe string is lifted up, the setting adapter leaves the ball seat, and the fracturing ball falls out of the ball seat abutment section of the push tube and falls into the wellbore;

[0049] Testing wellbore conditions;

[0050] When the wellbore condition is unqualified, the return well fluid flushes the fracturing ball into the first space, and the return well fluid stops;

[0051] Lift the setting tool and adapter out of the wellbore and remove the fracturing ball.

[0052] The beneficial effect of the fracturing ball recovery method of the present invention is that after the sealing is completed, the fracturing ball is sucked into the space accommodating the fracturing ball by directly returning the well fluid, thereby achieving the purpose of secondary pumping. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a cross-sectional view of a first state of a setting adapter embodiment 1 of the present invention;

[0054] Figure 2 is a cross-sectional view of the second state of the first embodiment;

[0055] Figure 3 It is an exploded diagram of a single-layer mechanism;

[0056] Figure 4 It is an exploded view of the first embodiment of the double-layer mechanism;

[0057] Figure 5 is an exploded view of the second embodiment of the double-layer mechanism;

[0058] Figure 6 It is an exploded view of an embodiment of a one-way passing mechanism of a variable diameter helical spring structure.

[0059] Figure 7 is a cross-sectional view of a first embodiment of a ball seat assembly;

[0060] Figure 8 is a view of the first embodiment of the ball seat assembly in one direction;

[0061] Fig. 9 It is a three-dimensional structural schematic diagram of the first embodiment of the ball seat assembly;

[0062] Fig.10 is a cross-sectional view of a first working state of a ball seat assembly embodiment 1;

[0063] Fig.11 is a cross-sectional view of the ball seat assembly embodiment 1 in the second working state;

[0064] Fig.12 is a cross-sectional view of the ball seat assembly embodiment 1 in the third working state;

[0065] Fig.13 is a cross-sectional view of the ball seat assembly embodiment 1 in the fourth working state;

[0066] Fig.14 is a cross-sectional view of the ball seat assembly embodiment 1 in the fifth working state;

[0067] Fig.15 is a cross-sectional view of the sealing ring in the second embodiment of the ball seat assembly;

[0068] Fig.16 is a cross-sectional view of the second embodiment of the ball seat assembly in the first working state;

[0069] Fig.17 is a cross-sectional view of the second working state of the ball seat assembly embodiment 2;

[0070] Fig.18 is a cross-sectional view of the ball seat assembly in the third working state of the second embodiment;

[0071] Fig.19 sectional view of the sealing ring in the third embodiment of the ball seat assembly

[0072] Fig. 20 is a cross-sectional view of the ball seat assembly embodiment 3 in the first working state;

[0073] Fig.21 is a cross-sectional view of the ball seat assembly in the second working state of the third embodiment;

[0074] Fig. 22 is a cross-sectional view of the third working state of the ball seat assembly embodiment 3;

[0075] Fig.23 is a cross-sectional view of another embodiment of a sealing ring;

[0076] Fig.24 is a cross-sectional view of yet another embodiment of the sealing ring;

[0077] Fig.25 is a cross-sectional view of the first embodiment of the skirt structure;

[0078] Fig.26 is a cross-sectional view of a second embodiment of the skirt structure;

[0079] Fig. 27 It is a cross-sectional view of the third embodiment of the skirt structure.

[0080] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0081] 1. Push cylinder, 11. Ball seat abutment section, 12. First space, 13. Second space, 2. Release lever, 21. Ball seat connection section, 3. One-way passing mechanism, 31. Shrapnel layer, 32. Shrapnel, 33. Retaining ring layer, 4. Fracturing ball, 5. Center pipe, 6. Sealing anchoring structure, 61. Sealing ring, 611 Sealing body, 612. Pumping body, 613. Slip contact surface, 614. Flange, 615. Skirt structure, 616. Skirt bottom, 617. Press ring, 618. Convex ring, 62. Slip assembly, 7. Lower joint, 8. Wellbore. DETAILED DESCRIPTION

[0082] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0083] See the structural diagram of the first embodiment of the setting adapter of the present invention. Figure 1 to Figure 2 .

[0084] A setting adapter includes a push tube 1 and a release lever 2; the push tube 1 has a ball seat abutment section 11, the ball seat abutment section 11 is used to abut and connect with the ball seat, and a one-way passing mechanism 3 for one-way passage of a fracturing ball 4 is provided in the ball seat abutment section 11, and the passing direction of the one-way passing mechanism 3 is a direction extending from the axial outer side to the inner side of the ball seat abutment section 11. In this embodiment, the push tube 1 is set as a two-section structure, that is, the ball seat abutment section 11 is set separately, and the push tubes 1 of different lengths can be finally configured.

[0085] The release lever 2 has a ball seat connection section 21, which passes through the one-way passing mechanism 3 for fitting and connecting with the ball seat. When the ball seat is set, the release lever 2 is retracted into the push tube 1. A first space 12 for accommodating the fracturing ball 4 is provided between the end of the release lever 2, the ball seat abutment section 11 and the one-way passing mechanism 3. In this embodiment, the release lever 2 is also configured as a two-stage structure. Since the overall length of the release lever 2 is relatively long, the two-stage structure shortens the length of a single rod and facilitates processing; at the same time, the two-stage structure can adjust the overall length.

[0086] In this embodiment, if Figure 1 As shown, the one-way passing mechanism 3 is arranged in the middle position of the ball seat abutment section 11, and the release lever 2 is retracted into the push tube 1, and a first space 12 that can accommodate the fracturing ball 4 is formed in the area of ​​the ball seat abutment section 11 on the left side of the one-way passing mechanism 3 and the end of the release lever 2.

[0087] like Figure 2 As shown, after the release lever 2 passes through the one-way passing mechanism 3 , a second space 13 for accommodating the fracturing ball 4 is provided between the ball seat abutment section 11 and the one-way passing mechanism 3 .

[0088] like Figure 7As shown, on the right side of the one-way passing mechanism 3, at the groove structure of the ball seat abutment section 11, the groove structure is the notch structure in the figure. Because the groove structure runs through the inner and outer surfaces of the ball seat connecting section 21, the space becomes larger here, and there is enough space to accommodate the fracturing ball 4. It should be noted that the circumferential width of the groove structure is smaller than the diameter of the fracturing ball, ensuring that the fracturing ball will not fall out of the ball seat connecting section 21 in the radial direction.

[0089] like Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, the groove structure can also be used to install the one-way passing mechanism 3. Figure 3 As shown, the circumferentially protruding portion of the spring sheet layer 31 is directly installed in the groove structure; Figure 4 and Figure 5 As shown, the circumferential protrusions of the spring sheet layer 31 and the retaining ring layer 33 are installed in the groove structure; Figure 6 As shown, the circumferential protrusion of the one-way passing mechanism 3 is installed in the groove structure.

[0090] The sealing adapter of this embodiment, after the sealing is completed, the release lever 2 is retracted into the push tube 1, and a first space 12 for accommodating the fracturing ball 4 is defined between the end of the release lever 2, the ball seat abutment section 11 and the one-way passage mechanism 3; when a secondary pumping operation is required, the fracturing ball 4 is returned and pushed into the first space 12 in the push tube 1 by backflow, and at the same time, the one-way passage mechanism 3 limits the fracturing ball 4 from falling off from the push tube 1, thereby ensuring the reliability of the recovery of the fracturing ball 4.

[0091] For a schematic diagram of a structural embodiment of the one-way passing mechanism 3, see Figure 3 , the one-way passing mechanism 3 is a single-layer mechanism, and the single-layer mechanism is a spring layer 31. The spring layer 31 has a plurality of springs 32. The aperture formed by the ends of the plurality of springs 32 is smaller than the diameter of the fracturing ball 4. The ends of the plurality of springs 32 extend obliquely in a direction away from the ball seat abutment section 11. In this embodiment, the spring layer 31 is configured as a circular thin sheet structure as a whole. Three protruding parts are provided at the edge of the thin sheet for fixed connection with the ball seat abutment section 11. Eight springs 32 are evenly distributed in the middle position of the thin sheet. The aperture formed by the ends of the eight springs 32 is smaller than the diameter of the fracturing ball 4. Three groove structures are provided in the axial direction of the ball seat abutment section 11. The bottom of the groove structure is located in the middle position of the ball seat abutment section. The protruding parts of the spring layer 31 are arranged at the bottom of the three groove structures and are fixedly connected. It should be noted that the number of springs 32 can be selected according to the actual working conditions, such as 3-10.

[0092] When the fracturing ball 4 needs to be recovered, the well fluid is returned and the fracturing ball 4 is pushed toward the right end of the one-way mechanism of the adapter by the well fluid. The fracturing ball 4 squeezes the end of the spring piece 32 of the spring piece layer 31. Since the entire spring piece 32 is in an unconstrained state and the end of the spring piece 32 is inclined inward, the entire spring piece 32 is easily deformed and the aperture becomes larger, and the fracturing ball 4 passes through the spring piece layer 31 and enters the first space 12. When the fracturing ball 4 enters the first space 12, the spring pieces 32 recover their deformation so that the aperture formed by the ends of the eight spring pieces 32 is smaller than the diameter of the fracturing ball 4. In the subsequent working process, if the fracturing ball 4 in the first space 12 is subjected to pressure to squeeze the spring piece layer 31, the ends of the spring pieces 32 in the spring piece layer 31 are still tilted inward, and it is difficult for the fracturing ball 4 to squeeze the spring pieces 32 to a direction perpendicular to the axis of the ball seat abutment section 11. The aperture formed by the ends of the spring pieces 32 cannot be smaller than the diameter of the fracturing ball 4, and thus the fracturing ball 4 cannot pass through the spring piece layer 31, ensuring that the fracturing ball 4 will not fall off from the first space 12, with high reliability.

[0093] See the schematic diagram of the second structural embodiment of the one-way passing mechanism 3. Figure 4 The one-way passing mechanism 3 is a double-layer mechanism, including a spring sheet layer 31 and a retaining ring layer 33. The spring sheet layer 31 has a plurality of spring sheets 32. The aperture formed at the ends of the plurality of spring sheets 32 is smaller than the diameter of the fracturing ball 4. The spring sheet layer 31 is arranged on the axial inner side of the ball seat abutment section 11; the retaining ring layer 33 has a through hole through which the fracturing ball 4 passes, and the retaining ring layer 33 is arranged on the axial outer side of the ball seat abutment section 11.

[0094] In this embodiment, the spring sheet layer 31 is configured as a circular thin sheet structure as a whole, and three protruding parts are provided at the edge of the thin sheet for fixed connection with the ball seat abutment section 11. Eight spring sheets 32 are evenly distributed in the middle position of the thin sheet, and the aperture formed by the ends of the eight spring sheets 32 is smaller than the diameter of the fracturing ball 4; three groove structures are provided in the axial direction of the ball seat abutment section 11, and the bottom of the groove structure is located in the middle position of the ball seat abutment section, and the protruding parts of the spring sheet layer 31 are arranged at the bottom of the three groove structures and fixedly connected. The retaining ring layer 33 is also configured as a thin sheet structure. Compared with the spring sheet layer 31, no spring sheet 32 ​​is provided. A through hole is provided in the middle of the retaining ring layer 33, and the aperture is slightly larger than the diameter of the fracturing ball 4, which is used for the fracturing ball 4 to pass through, and the aperture of the through hole is larger than the aperture formed by the ends of the eight spring sheets 32; the retaining ring layer 33 and the spring sheet layer 31 are stacked and fixed at the groove structure. In this embodiment, the spring sheet 32 ​​is perpendicular to the axis of the ball seat abutment section 11.

[0095] In this embodiment, the sealing adapter of this embodiment is used for downhole sealing. After the sealing is completed, the release lever 2 is retracted into the push tube 1. There is a first space 12 for accommodating the fracturing ball 4 between the end of the release lever 2, the ball seat abutment section 11 and the one-way passing mechanism 3. When the fracturing ball 4 needs to be recovered, the fracturing ball 4 is pushed back into the first space 12 in the push tube 1 by backflow. At the same time, the one-way passing mechanism 3 limits the fracturing ball 4 from falling off from the push tube 1, ensuring the reliability of the recovery of the fracturing ball 4. Specifically, during backflow, the fracturing ball 4 is pushed toward the ball seat abutment section of the adapter by the well fluid. Since the aperture of the retaining ring layer 33 is larger than the diameter of the fracturing ball 4, the fracturing ball 4 can pass through the retaining ring layer 33 and squeeze the end of the spring piece 32 of the spring piece layer 31. Since the entire spring piece 32 is in an unconstrained state, the entire spring piece 32 is deformed and the aperture becomes larger, and the fracturing ball 4 passes through the spring piece layer 31 into the first space 12. When the fracturing ball 4 enters the first space 12, the spring pieces 32 recover their deformation so that the aperture formed by the ends of the eight spring pieces 32 is smaller than the diameter of the fracturing ball 4. In the subsequent working process, if the fracturing ball 4 in the first space 12 is subjected to pressure to squeeze the spring piece layer 31, at this time, only the ends of the spring pieces 32 in the spring piece layer 31 are in a free state, and the other parts are constrained by the retaining ring layer 33 and cannot be deformed. Therefore, the fracturing ball 4 cannot pass through the spring piece layer 31, ensuring that the fracturing ball 4 will not fall off from the first space 12, and the reliability is very high.

[0096] See the schematic diagram of the third structural embodiment of the one-way passing mechanism 3. Figure 5 , which is also set to a double-layer structure, is different from the embodiment in that the ends of the multiple spring pieces 32 extend obliquely in a direction away from the ball seat abutment section 11, that is, the free ends of the spring pieces 32 extend inward. Since the entire spring piece 32 is in an unconstrained state and the ends of the spring piece 32 are inclined inward, the entire spring piece 32 is easily deformed and the aperture becomes larger, so that the fracturing ball 4 can easily pass through the spring piece layer 31 and enter the first space 12. Similarly, due to the combined effect of the inclined spring piece 32 and the retaining ring layer 33, the fracturing ball 4 cannot fall out of the first space 12.

[0097] See the schematic diagram of another embodiment of the structure of the one-way passing mechanism 3. Figure 6 In this embodiment, the one-way passing mechanism 3 is a variable diameter coil spring structure, and the small end of the variable diameter coil spring extends obliquely in the direction away from the ball seat abutment section. In the adapter of this embodiment, the middle through hole of the variable diameter coil spring is smaller than the fracturing ball. When the fracturing ball is recovered, the fracturing ball enters the variable diameter coil spring structure from the right end. When the impact force of the return flow on the fracturing ball is large, the aperture of the middle through hole becomes larger, and the fracturing ball smoothly passes through the variable diameter coil spring structure into the first space; due to the variable diameter coil spring structure, the fracturing ball will not fall off from the first space, that is, the fracturing ball will not fall off from the left end. .

[0098] Embodiment 1 of the ball seat assembly of the present invention is shown in Figures 7 to 9 , including a ball seat body and an adapter, the adapter is the above-mentioned setting adapter, the ball seat body includes a central tube 5, a sealing anchor structure 6 and a lower joint 7, the sealing anchor structure 6 is sleeved on the central tube 5, the lower joint 7 is located at an end away from the central tube 5 and abuts against the sealing anchor structure 6; the ball seat abutting section 11 abuts against the central tube 5, and the ball seat connecting section 21 is connected to the lower joint 7. In this embodiment, the second space 13 is provided with a fracturing ball 4.

[0099] In this embodiment, the sealing anchoring structure 6 includes a sealing ring 61 and a slip assembly 62 . The slip assembly 62 is a split slip. The slip assembly 62 is then integrated into an integral structure through a spiral structure at one end abutting against the sealing ring 61 .

[0100] The working process of the ball seat assembly application in this embodiment can be found in Figures 10 to 14 ,like Fig.10 As shown, the ball seat body is pumped to the designated position in the wellbore 8, and the setting is completed by the setting tool. After the setting is completed, the adapter is removed from the ball seat by lifting the pipe string. At this time, Fig.11 As shown, the fracturing ball 4 falls from the second space 13 into the wellbore 8. Fig.12 As shown, during the ball seat sealing or fracturing, the fracturing ball 4 falls into the sealing position of the central pipe 5. In the case of a perforation operation failure, it is necessary to start the fracturing ball 4 capture scheme, such as Fig.13 and Fig.14 As shown, at this time, the fracturing ball 4 is backflowed into the first space 12 in the push tube 1 by backflow; the fracturing ball 4 is recovered underground, the adapter is lifted out of the wellbore 8, and the fracturing ball 4 is taken out; after the fracturing ball 4 is taken out, other subsequent operations are performed.

[0101] For the second embodiment of the ball seat assembly of the present invention, see Figures 15 to 18 , which is different from the first embodiment, in that the sealing ring 61 includes a sealing body 611 and a pumping body 612, and the sealing body 611 and the pumping body 612 are an integrated structure; the contact surface between the sealing body 611 and the slip assembly 62 is a slip contact surface 613, and the slip contact surface 613 is an inclined surface, which is used to abut against the slip assembly 62 and press the sealing body 611; the pumping body 612 is an outwardly turned skirt structure 615. Among them, the skirt structure 615 is close to the end of the sealing body 611 as the skirt bottom 616, and the skirt structure 615 has a stepped multi-level structure with gradually increasing thickness in the direction extending toward the skirt bottom 616.

[0102] The sealing ring 61 includes a sealing body 611 and a pumping body 612. Fig.15As shown, the right side is a sealing body 611, and the left side is a pumping body 612. The sealing body 611 and the pumping body 612 are an integrated structure to form a sealing ring 61; the abutting surface of the sealing body 611 and the slip assembly 62 is a slip contact surface 613, and the slip contact surface 613 is an inclined surface, which is used to abut against the slip assembly 62 and press the sealing body 611. The sealing body 611 is provided with a flange 614 protruding toward the slip assembly 62 at the abutting point with the slip assembly 62; the pumping body 612 is an outward-turned skirt structure 615. The sealing ring 61 has the functions of sealing and pumping, and is generally made of rubber or a plastic material with high ductility and high toughness.

[0103] The skirt structure 615 is close to the end of the sealing body 611 as the skirt bottom 616, and the thickness of the skirt structure 615 gradually increases in the direction of extension toward the skirt bottom 616. The outer wall of the skirt structure 615 and the outer wall of the sealing body 611 are in a coplanar state. The sealing ring 61. In this embodiment, the inner diameter of the sealing ring 61 is set as a tapered hole structure, and the small end of the tapered hole structure is located at the end of the sealing body 611. In this embodiment, a pressure ring 617 is provided on the sealing body 611 near the skirt bottom 616, and a flange 614 is provided on the sealing body 611.

[0104] The inner surface of the sealing body 611 is provided with a convex ring 618 structure, and the top of the convex ring 618 structure extends to the slip contact surface 613 of the sealing body 611, that is, the right end as shown in the figure. By providing the convex ring 618 structure, the convex ring 618 structure is matched and connected with the groove of the center pipe 5. During the pumping process, the sealing pumping sealing ring 61 will not fall off the center pipe 5, further ensuring the reliability of the pumping; at the same time, when setting the seal, the convex ring 618 structure is pressed against the outer wall of the center pipe 5, increasing the thickness of the sealing body 611 and improving the sealing reliability of the sealing body 611.

[0105] The recovery process of the fracturing ball 4 of the ball seat assembly in this embodiment is the same as the working principle and process of the first embodiment, which will not be repeated here. The sealing and pumping functions of the sealing ring 61 of the ball seat assembly will be described below. Fig.16 , that is, the state of the ball seat assembly just put into the wellbore 8 and before pumping. The ball seat assembly is located in the middle of the wellbore 8. Since it is not in the pumping state, the skirt structure 615 of the pumping body 612 in the sealing ring 61 is in a normal state without eversion.

[0106] The second working state of the pumping working process of the second embodiment is shown in FIG. Fig.17 , that is, the ball seat assembly is in the wellbore 8 and is in the state of pumping. Fig.17On the left side shown, the pumping liquid is input, and the flow direction of the pumping liquid is from left to right. Due to the pressure of the pumping liquid, the skirt structure 615 of the pumping body 612 turns outward, and the pumping liquid generates thrust on the entire ball seat assembly, pushing the ball seat assembly forward. During the pumping process of the ball seat assembly, the pressure ring 617 always keeps the pressure on the pumping body 612, that is, the pressure ring 617 always presses the pumping body 612 on the central tube 5, and the sealing ring 61 will not be washed away by the pumping pressure, ensuring reliability.

[0107] The third working state of the pumping working process of the second embodiment is shown in FIG. Fig.18 , that is, the ball seat assembly is in the state of being set after pumping is completed in the wellbore 8. After setting, the slip teeth in the slip assembly 62 are anchored to the inner wall of the wellbore 8, and the sealing body 611 in the sealing ring 61 is abutted and sealed against the inner wall of the wellbore 8. In this embodiment, after setting, part of the slip assembly 62 plays a compressive supporting role on the flange 614, and the flange 614 plays a good auxiliary sealing role.

[0108] For the third embodiment of the ball seat assembly of the present invention, see Figures 19 to 22 , compared with the second embodiment, the difference is that, Fig.18 As shown, the cross section of the pressure ring 617 in this embodiment is circular, and it abuts against the skirt structure 615 at the position of the skirt bottom 616. This structure not only further ensures the reliability and stability of the sealing ring 61 during the pumping process, that is, during the pumping process, the pressure ring 617 always maintains a pressing effect on the pumping body 612, and the entire sealing ring 61 will not be washed away by the pumping pressure. At the same time, after the setting is completed, the pressure ring 617 will support the skirt structure 615, thereby making the skirt structure 615 abut against the inner wall of the wellbore 8 and achieve auxiliary sealing.

[0109] The pumping working process of the ball seat assembly of this embodiment 3 is shown in FIG. Figure 20 to Figure 21 The state change of the sealing ring 61 during the working process is consistent with the process in the second embodiment. Fig. 22 After the seal is set, the slip teeth in the slip assembly 62 are anchored to the inner wall of the wellbore 8, and the sealing body 611 in the sealing ring 61 is in contact with the inner wall of the wellbore 8 for sealing. In this embodiment, after the seal is set, the pressure ring 617 supports the skirt structure 615, thereby making the skirt structure 615 close to the inner wall of the wellbore 8 and achieving auxiliary sealing.

[0110] See the cross-sectional view of another embodiment of the sealing ring 61. Fig.23 In this embodiment, compared with the sealing ring 61 in the second embodiment of the ball seat assembly, the difference is that the inner surface of the sealing body 611 is not provided with a convex ring 618 structure, and this structure is simpler.

[0111] A cross-sectional view of another embodiment of the sealing ring 61 is shown in FIG. Fig.24 In this embodiment, compared with the sealing ring 61 in the third embodiment of the ball seat assembly, the difference is that the slip contact surface 613 is a vertical surface, and the bottom 616 of the skirt is not provided with a groove structure; the skirt structure 615 is provided with multiple openings in the circumferential direction. At the same time, a pressure ring 617 is provided on the outer cylindrical surface between the sealing body 611 and the pumping body 612. Specifically, the outer cylindrical surface of the pressure ring 617 is not higher than the surface of the sealing body 611.

[0112] Regarding the skirt structure 615 of the sealing ring 61 , the present invention provides the following three embodiments for illustration.

[0113] The cross-sectional view of the first embodiment of the skirt structure 615 is shown in Fig.25 The skirt is set to a structure with multiple tapers, that is, at the top of the skirt, the taper is smaller and the skirt is thinner; near the bottom 616 of the skirt, the taper is larger and the skirt is thicker, forming a structure in which the thickness gradually increases from the edge position of the skirt to the extension direction of the bottom 616 of the skirt.

[0114] The cross-sectional view of the second embodiment of the skirt structure 615 is shown in Fig.26 ,and Fig.25 In comparison, the tapers in the skirt structure 615 are the same, except that steps are provided between adjacent tapers, that is, a stepped multi-level structure is formed as a whole. This structure has a better effect of opening step by step when the pumping displacement is low.

[0115] The cross-sectional view of the third embodiment of the skirt structure 615 is shown in Fig. 27 ,and Fig.26 In comparison, there is no tapered structure and each step is a cylindrical structure.

[0116] This embodiment also provides two methods for recovering fracturing balls, wherein one method for recovering fracturing balls includes using the above-mentioned setting adapter, and the specific steps include:

[0117] Remove the hand lever from the adapter.

[0118] At the section away from the ball seat abutment, the push cylinder is connected to the lowest part of the pipe string connected to the oil or cable.

[0119] The push tube is lowered into a set position underground.

[0120] The return well fluid flushes the captured sphere into the first space.

[0121] The pipe string is lifted out of the wellbore, and the captured ball is removed, and the return of well fluid is stopped. The above-mentioned fracturing ball recovery method is applicable to any working condition that requires the recovery of the captured ball. It only needs to install the setting adapter, which is very efficient and reliable.

[0122] Another method for recovering a fracturing ball includes using the above-mentioned ball seat assembly, and the specific steps include:

[0123] The ball seat assembly of the sealing tool is sent into the preset position in the wellbore to complete the sealing.

[0124] Setting Tool Setting adapter off the ball seat.

[0125] The setting tool continues to work, retracts the release hand into the push tube, and has a first space for accommodating the fracturing ball between the ball seat connecting section and the one-way passing mechanism.

[0126] The fracturing ball falls out of the ball seat abutment section of the push tube and falls into the wellbore.

[0127] Test wellbore condition.

[0128] When the wellbore condition is unqualified, the return well fluid will flush the fracturing ball into the first space and stop the return well fluid.

[0129] Lift the setting tool and adapter out of the wellbore and remove the fracturing ball.

[0130] Specifically, this embodiment lists the working process of the underground perforating operation to explain the method of the present invention in detail.

[0131] Downhole perforation is an important operation in the process of oil drilling and completion. It aims to open the oil layer through the perforating gun so that the fluid in the formation can flow into the wellbore, so as to carry out oil and gas production operations.

[0132] The perforating gun string, the setting tool and the ball seat assembly in this embodiment are assembled, the seat assembly group is pumped to a predetermined position, the setting tool starts the work, and the ball seat completes the setting.

[0133] The sealing tool continues to move until the entire stroke is completed; at this time, since the sealing tool moves with the push tube of the adapter, the release lever retracts into the push tube, forming a first space for accommodating the fracturing ball.

[0134] The pipe string is lifted up, and the fracturing ball falls into the wellbore from the first space of the push tube.

[0135] Continue to lift the pipe string to the perforating section and complete the perforating operation.

[0136] If the perforating operation is normal, lift the pipe string to the wellhead and remove the pipe string.

[0137] Then turn on the pump, the fracturing ball sits on the ball seat, and fracturing begins.

[0138] If perforation failure is found, the fracturing ball recovery plan needs to be initiated.

[0139] Start the flowback. The specific method is: open the valve at the wellhead, and the high-pressure fluid at the bottom of the well will flow from the bottom of the well to the wellhead. At this time, the fluid will carry the fracturing ball to the wellhead, thereby flushing the fracturing ball into the push tube of the adapter.

[0140] Close the wellhead valve, pull the pipe string up to the wellhead, and remove the adapter and fracturing ball.

[0141] Replace the perforating gun string and re-enter the well.

[0142] The pump pipe string is moved to the location where perforation is required to complete the perforation operation.

[0143] Lift the pipe string to the wellhead and remove the pipe string.

[0144] Re-inject the fracturing ball, pump it, and let the fracturing ball sit on the ball seat.

[0145] Complete fracking.

[0146] The above specific embodiments are only specific examples to facilitate understanding of the technical solutions of the present invention.

[0147] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A setting adapter, characterized in that it includes a push cylinder and a release lever; The push cylinder has a ball seat abutment section, the ball seat abutment section is used to abut and connect with the ball seat, and a one-way passing mechanism for one-way passage of the fracturing ball is provided in the ball seat abutment section, and the passing direction of the one-way passing mechanism is a direction extending from the axial outer side of the ball seat abutment section to the inner side thereof; The release lever has a ball seat connecting section, and the ball seat connecting section passes through the one-way passing mechanism for adapting and connecting with the ball seat. When the ball seat is sealed, the release lever retreats into the push cylinder, and a first space for accommodating the fracturing ball is defined between the end of the release lever, the ball seat abutting section and the one-way passing mechanism.

2. A setting adapter according to claim 1, characterized in that: The one-way passing mechanism is a single-layer mechanism, which is a spring layer. The spring layer has a plurality of springs. The aperture formed by the ends of the plurality of springs is smaller than the diameter of the fracturing ball. The ends of the plurality of springs extend obliquely away from the ball seat abutment section.

3. A setting adapter according to claim 2, characterized in that: The spring sheet has a first end and a second end, the first end is connected with the outer ring to form an integral structure, the outer ring is fixedly arranged on the ball seat abutment section, and the second end extends obliquely in a direction away from the ball seat abutment section.

4. The setting adapter according to claim 1, characterized in that: The one-way passing mechanism is a double-layer mechanism, including a spring sheet layer and a retaining ring layer, the spring sheet layer has a plurality of spring sheets, the aperture formed by the ends of the plurality of spring sheets is smaller than the diameter of the fracturing ball, and the spring sheet layer is arranged on the axial inner side of the ball seat abutment section; the retaining ring layer has a through hole through which the fracturing ball passes, the diameter of the through hole is larger than the diameter of the fracturing ball, and the retaining ring layer is arranged on the axial outer side of the ball seat abutment section.

5. The setting adapter according to claim 1, characterized in that: The one-way passing mechanism is a variable diameter coil spring structure, the diameter of the middle hole of the variable diameter coil spring structure is smaller than the diameter of the fracturing ball, and the small end of the variable diameter coil spring extends obliquely in a direction away from the ball seat abutment section.

6. A setting adapter according to any one of claims 1 to 5, characterized in that: It also includes a second space for accommodating the fracturing ball. When the release rod passes through the one-way passing mechanism, the second space is formed between the ball seat abutment section and the release rod.

7. A setting adapter according to claim 6, characterized in that: An axial groove is provided on the ball seat abutment section between the one-way passing mechanism and the ball seat, and a second space for accommodating the fracturing ball is formed at the axial groove, and the axial groove is used to fix the one-way passing mechanism.

8. A ball seat assembly, comprising a ball seat body and an adapter, characterized in that: The adapter is the sealing adapter according to any one of claims 1 to 7, the ball seat body includes a center tube, a sealing anchoring structure and a lower joint, the sealing anchoring structure is sleeved on the center tube, the lower joint is located at an end away from the center tube and abuts against the sealing anchoring structure; the ball seat abutting section abuts against the center tube, and the ball seat connecting section is connected to the lower joint.

9. A ball seat assembly according to claim 8, characterized in that: The sealing anchoring structure includes a sealing ring and a slip assembly, the sealing ring includes a sealing body and a pumping body, the sealing body and the pumping body are an integral structure; the contact surface between the sealing body and the slip assembly is a slip contact surface, and the slip contact surface is an inclined surface, which is used to abut against the slip assembly and press the sealing body; the pumping body is an outwardly turnable skirt structure; the skirt structure is close to the end of the sealing body as the skirt bottom, and the skirt structure is a stepped multi-level structure with a thickness gradually increasing in the direction extending toward the skirt bottom; the skirt structure is provided with a plurality of openings on the circumference, and the plurality of openings are evenly distributed on the circumference of the skirt structure.

10. A ball seat assembly according to claim 9, characterized in that: A flange protruding toward the slip assembly is provided on the sealing body at the point where it abuts against the slip assembly, and the flange is used to cover part of the slip assembly; a convex ring structure is provided on the inner surface of the sealing body, and the top end of the convex ring structure extends toward the slip assembly.

11. A ball seat assembly according to claim 10, characterized in that: It also includes a pressure ring, which is arranged at the bottom of the skirt; or, the pressure ring is arranged on the circumference of the outer cylindrical surface between the sealing body and the pumping body.

12. A method for recovering a fracturing ball, characterized in that: The method comprises using the setting adapter according to any one of claims 1 to 7, wherein the specific steps include: removing the release lever from the adapter; At the section away from the ball seat abutment, the push cylinder is connected to the bottom of the pipe string connected to the oil or cable. Lowering the push tube to a set position underground; The return well fluid flushes the captured sphere into the first space, and the return well fluid stops; The tubing string is lifted out of the wellbore and the captured ball is removed.

13. A method for recovering a fracturing ball, characterized in that: The method comprises adopting the ball seat assembly according to any one of claims 8 to 11, and the specific steps include: The ball seat assembly enters the preset position of the wellbore, the sealing tool starts to work, and the ball seat completes the sealing; The setting tool continues to work, the release lever is retracted into the push cylinder, and a first space for accommodating the fracturing ball is formed between the ball seat connecting section and the one-way passing mechanism; The pipe string is lifted up, the setting adapter leaves the ball seat, and the fracturing ball falls out of the ball seat abutment section of the push tube and falls into the wellbore; Testing wellbore conditions; When the wellbore condition is unqualified, the return well fluid flushes the fracturing ball into the first space, and the return well fluid stops; Lift the setting tool and adapter out of the wellbore and remove the fracturing ball.

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