Bridge plug and production pipe string

Abstract

A bridge plug and a production pipe string. The bridge plug comprises a slip (1), a first expansion body (2), a second expansion body (3), a first pipe portion (4) and a second pipe portion (5), wherein the bridge plug can be configured in such a way that the first expansion body (2) is inserted into an upper end of the slip (1), and the second expansion body (3) can be inserted into a lower end of the slip (1), thereby making the slip (1) expand in a radial direction for the first time; and the first expansion body (2) and the second expansion body (3) can respectively expand in the radial direction, thereby making the slip (1) expand in the radial direction for the second time. The two expansion bodies can press the slip by means of a tapered outer peripheral surface so as to realize primary expansion, and the slip is expanded once more by means of the expansion of the two expansion bodies themselves, such that two instances of expansion of the slip can be realized; therefore, an expansion rate of the slip is improved, and an extreme variable-diameter casing packing operation can be realized.

Description

Bridge plug and production string

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202310721176.5 filed on June 16, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] Technical Field

[0004] The present invention relates to oil and gas downhole construction, in particular to a bridge plug and a production tubing string. Background Art

[0005] In the field of oil and gas development, casing isolation operations are required under extreme casing deformation conditions. The tool used in this case is required to have the smallest possible outer diameter and expand to the largest possible outer diameter after being lowered into the operating position. Therefore, to achieve this isolation operation, a bridge plug with a large expansion rate is required. However, the expansion rate of existing bridge plugs is insufficient and therefore cannot achieve the above function.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a downhole bridge plug with a high expansion rate, which is suitable for extremely variable diameter casing and effectively solves the problems of large annular space setting, anchoring and sealing.

[0008] In order to achieve the above-mentioned objectives, the present invention provides a bridge plug on one hand, characterized in that the bridge plug includes a cava, a first expansion body having a tapered first outer peripheral surface, a second expansion body having a tapered second outer peripheral surface, a first tube portion having a tapered third outer peripheral surface and a second tube portion having a tapered fourth outer peripheral surface. The bridge plug can be configured as follows: the first expansion body is inserted into the upper end of the cava, and the second expansion body is inserted into the lower end of the cava, so that the first outer peripheral surface and the second peripheral surface can squeeze the cava to cause the cava to undergo a first radial expansion; the first tube portion is inserted into the first expansion body and the second tube portion is inserted into the second expansion body, so that the first expansion body and the second expansion body can expand radially respectively, thereby causing the cava to undergo a second radial expansion.

[0009] In some embodiments, the bridge plug can be configured such that: the first pipe portion pushes the first expansion body to gradually insert into the upper end of the cava, while the second pipe portion pushes the second expansion body to gradually insert into the lower end of the cava, so that the cava first performs the first radial expansion and then performs the second radial expansion.

[0010] In some embodiments, the force required for radial expansion of the first expansion body and the force required for radial expansion of the second expansion body are respectively greater than the force required for radial expansion of the slips.

[0011] In some embodiments, the first expansion body includes a tapered first main body and a first support ring connected to a large end of the first main body, and the second expansion body includes a tapered second main body and a second support ring connected to a large end of the second main body.

[0012] In some embodiments, the force required for the first support ring to break is greater than the force required for the slips to radially expand, and the force required for the second support ring to break is greater than the force required for the slips to radially expand.

[0013] In some embodiments, the first main body portion includes a plurality of first expansion plates arranged circumferentially, and the second main body portion includes a plurality of second expansion plates arranged circumferentially.

[0014] In some embodiments, the first expansion plate is integrally connected to the first support ring, and the second expansion plate is integrally connected to the second support ring.

[0015] In some embodiments, the slips include a plurality of tooth plates arranged circumferentially.

[0016] In some embodiments, the slips include sealing rings connected to both ends of the tooth plate.

[0017] In some embodiments, the number of the tooth plates, the number of the first expansion plates, and the number of the second expansion plates are the same.

[0018] In some embodiments, the inner surface of the tooth plate is provided with a first limiting groove, and the outer surface of the first expansion plate is provided with a first limiting strip, and the first limiting grooves can respectively guide the first limiting strip to move axially.

[0019] In some embodiments, a second limiting groove is provided on the inner surface of the tooth plate, and a second limiting strip is provided on the outer surface of the second expansion plate, and the second limiting groove can guide the second limiting strip to move axially.

[0020] In some embodiments, a ball pitching seat is provided at the upper end of the first tube portion.

[0021] In some embodiments, the first pipe portion includes a first reducer and a first circular pipe connected to a large end of the first reducer, and the second pipe portion includes a second reducer and a second circular pipe connected to a large end of the second reducer.

[0022] On the other hand, the present solution provides a production string, wherein the production string includes a continuous oil pipe, a setting tool, a center rod and a bridge plug arranged on the center rod, which are connected in sequence. The bridge plug is the bridge plug described in the above solution.

[0023] In some embodiments, the operation process of the production string is:

[0024] First, the bridge plug, the center rod, the setting tool and the coiled tubing are connected in sequence and lowered to the designed position. Pressure is applied to the setting tool through the wellhead to compress the first expansion body and the second expansion body respectively to expand, so that the slips undergo two radial expansions to achieve setting and sealing. Then, the coiled tubing is lifted to drive the center rod and the setting tool to separate from the bridge plug and lift them to the wellhead for removal. Then, a sealing soluble ball is pumped to seal the sealing soluble ball with the first expansion body. Finally, the wellhead is lifted to perform fracturing construction to obtain a new fracturing crack.

[0025] Through the above technical solution, the two expansion bodies can achieve one expansion by squeezing the slips through the gradually shrinking outer peripheral surface, and achieve another expansion of the slips through the expansion of the two expansion bodies themselves, thereby achieving two expansions of the slips, improving the expansion rate of the slips, and realizing extreme casing change sealing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a bridge plug in a first working state according to an embodiment of the present invention;

[0027] FIG2 is a cross-sectional view of FIG1 ;

[0028] FIG3 is a schematic structural diagram of the bridge plug in the second working state according to the embodiment of the present invention;

[0029] FIG4 is a cross-sectional view of FIG3;

[0030] FIG5 is a schematic structural diagram of the bridge plug in the third working state according to the embodiment of the present invention;

[0031] FIG6 is a cross-sectional view of FIG5;

[0032] FIG7 is a schematic diagram of a production string according to an embodiment of the present invention;

[0033] FIG8 is a schematic structural diagram of a production string in a first working state according to an embodiment of the present invention;

[0034] FIG9 is a schematic structural diagram of a production string in a second working state according to an embodiment of the present invention;

[0035] FIG10 is a schematic diagram of placing sealing soluble balls during the construction process;

[0036] FIG11 is a schematic diagram of new cracks generated by fracturing construction.

[0037] EXPLANATION OF REFERENCE NUMERALS: 1-slip, 11-tooth plate, 12-sealing ring, 2-first expansion body, 21-first support ring, 22-first main body, 3-second expansion body, 31-second support ring, 32-second main body, 4-first tubular portion, 41-first circular tubular portion, 42-first reducer, 5-second tubular portion, 51-first circular tubular portion, 52-second reducer, 6-coiled tubing, 7-setting tool, 8-casing, 9-center rod, 10-sealable soluble ball, 11-fracturing fracture. DETAILED DESCRIPTION

[0038] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0039] In the present invention, unless otherwise specified, directional words such as "upper" and "lower" generally refer to relative positional relationships in the state of use, but this is only for the purpose of more clearly describing the present solution and should not be understood as a special limitation on the present solution.

[0040] Example 1

[0041] Referring to Figures 1 to 6, the present solution provides a bridge plug, wherein the bridge plug includes a cava 1, a first expansion body 2 having a tapered first outer peripheral surface, a second expansion body 3 having a tapered second outer peripheral surface, a first pipe portion 4 having a tapered third outer peripheral surface, and a second pipe portion 5 having a tapered fourth outer peripheral surface. The bridge plug can be configured as follows: the first expansion body 2 is inserted into the upper end of the cava 1, and the second expansion body 3 is inserted into the lower end of the cava 1, so that the first outer peripheral surface and the second outer peripheral surface can squeeze the cava 1 so that the cava 1 undergoes a first radial expansion; the first pipe portion 4 is inserted into the first expansion body 2 and the second pipe portion 5 is inserted into the second expansion body 3, so that the first expansion body 2 and the second expansion body 3 can expand radially respectively, so that the cava 1 undergoes a second radial expansion.

[0042] The first expansion body 2 and the second expansion body 3 can be of similar or identical structure, and are respectively formed into a tubular shape and have a tapered outer peripheral surface. The outer diameter of the small end of the first expansion body 2 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the first expansion body 2 is larger than the inner diameter of the slip 1. The outer diameter of the small end of the second expansion body 3 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the second expansion body 3 is larger than the inner diameter of the slip 1. Therefore, when the first expansion body 2 is inserted into the upper end of the slip 1 through its small end, a radially outward force can be applied to the inner peripheral surface of the slip 1 through the first outer peripheral surface of the first expansion body 2, so that the slip 1 expands radially outward. Similarly, when the second expansion body 3 is inserted into the lower end of the slip 1 through its small end, the slip 1 also expands radially outward. That is to say, by inserting the first expansion body 2 and the second expansion body 3 into the two ends of the slip 1 respectively, the overall radial expansion of the slip 1 can be achieved.

[0043] The first tube portion 4 has a tapered outer circumferential surface, the second tube portion 5 has a tapered outer circumferential surface, the outer diameter of the small end of the first tube portion 4 is smaller than the inner diameter of the large end of the first expansion body 2, the outer diameter of the large end of the first tube portion 4 is larger than the inner diameter of the large end of the first expansion body 2, the outer diameter of the small end of the second tube portion 5 is smaller than the inner diameter of the large end of the second expansion body 3, and the outer diameter of the large end of the second tube portion 5 is larger than the inner diameter of the large end of the second expansion body 3. Correspondingly, in the process of inserting the small end of the first tube part 4 into the large end of the first expansion body 2, the first tube part 4 applies a radially outward extrusion force to the first expansion body 2, so that the first expansion body 2 expands radially outward, and the radial expansion of the first expansion body 2 causes the cava 1 to expand radially again; similarly, in the process of inserting the small end of the second tube part 5 into the large end of the second expansion body 3, the second tube part 5 applies a radially outward extrusion force to the second expansion body 3, so that the second expansion body 3 expands radially outward, and the radial expansion of the second expansion body 3 causes the cava 1 to expand radially again. Therefore, the second radial expansion of the cava 1 can be achieved through the radial expansion of the first expansion body 2 and the second expansion body 3.

[0044] In this solution, the two expansion bodies can achieve one expansion by squeezing the slips through the tapered outer surface, and achieve another expansion of the slips through the expansion of the two expansion bodies themselves, thereby achieving two expansions of the slips, improving the expansion rate of the slips, and realizing extreme casing change sealing operations.

[0045] Furthermore, the bridge plug can be configured as follows: the first pipe portion 4 pushes the first expansion body 2 to gradually insert into the upper end of the slip 1, while the second pipe portion 5 pushes the second expansion body 3 to gradually insert into the lower end of the slip 1, so that the slip 1 first undergoes the first radial expansion and then the second radial expansion. That is, the insertion of the first expansion body 2 into the slip 1 is achieved by the push of the first pipe portion 4, and the insertion of the second expansion body 3 into the lower end of the slip 1 is achieved by the push of the second pipe portion 5. It is only necessary to insert the first pipe portion 4 into the first expansion body 2 and the second expansion body 2 into the slip 1, and then push the first pipe portion 4. On the other hand, insert the second pipe portion 5 into the second expansion body 3 and the second expansion body 3 into the slip 1, and then push the second pipe portion 5, so that the two expansions of the slip 1 can be achieved in sequence. Of course, in other embodiments, the two expansion bodies can be inserted into the slip 1 respectively to achieve the first expansion, and then the two pipe portions can be inserted respectively to achieve the second expansion of the slip 1.

[0046] In addition, the force required for the radial expansion of the first expansion body 2 and the force required for the radial expansion of the second expansion body 3 are respectively greater than the force required for the radial expansion of the slip 1. The extrusion force required for the slip 1 to begin expanding is less than the extrusion force required for the expansion of the first expansion body 2 and the extrusion force required for the expansion of the second expansion body 3. When the first tube 4 is inserted into the first expansion body 2 and the second expansion body 2 is inserted into the slip 1, the force exerted by the first tube 4 on the second expansion body 2 is transmitted to the slip 1. Therefore, the slip 1 will first begin to expand. As the first tube 4 is gradually inserted into the second expansion body 2, its extrusion force increases. When the force required for the expansion of the first expansion body 2 is reached, the second expansion body 2 begins to expand. In other words, as the first tube 4 is gradually inserted into the first expansion body 2, the second expansion body 2 is also gradually inserted into the slip 1, first achieving the first radial expansion of the slip 1, and then achieving the second radial expansion of the slip 1 through the expansion of the second expansion body 2. The second expansion body 3 and the second tube 5 are also similarly configured and will not be repeated here.

[0047] The first expansion body 2 includes a tapered first main body portion 22 and a first support ring 21 connected to the large end of the first main body portion 22. The second expansion body 3 includes a tapered second main body portion 32 and a second support ring 31 connected to the large end of the second main body portion 32. The small end of the first main body portion 22 is used to be inserted into the upper end of the slip 1, and the small end of the second main body portion 32 is used to be inserted into the lower end of the slip 1. The first support ring 21 is connected to the large end of the first main body portion 22 and can allow the first pipe portion 4 to be inserted. The second support ring 31 is connected to the large end of the second main body portion 32 and can allow the second pipe portion 5 to be inserted.

[0048] Furthermore, the force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1, and the force required for the second support ring 31 to break is greater than the force required for the radial expansion of the slip 1. The first support ring 21 is configured as a structure that limits the expansion of the first expansion body 2, that is, the first support ring 21 needs to be broken first, and the extrusion force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1. Therefore, in the process of inserting the first expansion body 2 into the first tube 4 and the second expansion body 2 into the slip 1, the slip 1 begins to expand first, and then the first tube 4 squeezes the first support ring 21 to break, and the first main body 22 begins to expand, so as to act on the slip 1 to achieve its second radial expansion. The second expansion body 3 and the second tube 5 are also configured similarly and will not be repeated here.

[0049] The first main body 22 includes a plurality of circumferentially arranged first expansion plates, and the second main body 32 includes a plurality of circumferentially arranged second expansion plates. The first expansion plates are circumferentially arranged, and when the first expansion body 2 radially expands, the circumferential spacing between adjacent first expansion plates increases, thereby enabling expansion and deployment of the first main body 22. Similarly, the second expansion plates are circumferentially arranged, and when the second expansion body 3 radially expands, the circumferential spacing between adjacent second expansion plates increases, thereby enabling expansion and deployment of the second main body 32.

[0050] The first expansion plate is integrally connected to the first support ring 21, and the second expansion plate is integrally connected to the second support ring 31. The plurality of first expansion plates and the first support ring 21 are integrally connected to form a whole. When the first support ring 21 is broken into a plurality of circumferentially arranged parts, the plurality of first expansion plates can be allowed to expand away from each other. Similarly, the plurality of second expansion plates and the second support ring 31 are integrally connected to form a whole. When the second support ring 31 is broken into a plurality of circumferentially arranged parts, the plurality of second expansion plates can be allowed to expand away from each other. Furthermore, the first support ring 21 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of first expansion plates. The second support ring 31 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of second expansion plates.

[0051] The slips 1 include multiple tooth plates 11 arranged circumferentially. During expansion, the circumferential spacing between the tooth plates 11 increases, enabling radial expansion. Slip teeth can be provided on the outer surfaces of the tooth plates 11, allowing them to engage with the inner circumferential surface of the sleeve.

[0052] In addition, the slips 1 include sealing rings 12 connected to both ends of the tooth plate 11. The sealing rings 12 are made of a sealing material, which can be a plastic material or an elastic material. When the tooth plate 11 expands and expands, the sealing rings 12 also expand, and the outer circumference of the sealing ring 12 can fit the inner circumference of the casing to form a seal.

[0053] Furthermore, the number of tooth plates 11, the number of first expansion plates, and the number of second expansion plates are the same. The first expansion plates can correspond one to one with the tooth plates 11, and the second expansion plates can correspond one to one with the tooth plates 11, i.e., radially aligned, facilitating synchronous radial outward expansion and reducing circumferential relative displacement between the first and second expansion plates and the tooth plates 11. Specifically, the number of tooth plates 11, the number of first expansion plates, and the number of second expansion plates can each be six.

[0054] Furthermore, the inner surface of the tooth plate 11 is provided with a first limiting groove, and the outer surface of the first expansion plate is provided with a first limiting strip. The first limiting groove can respectively guide the first limiting strip to move axially. The first limiting groove extends axially, and the first limiting strip also extends roughly axially. Of course, there is a certain angle between the extension direction and the axial direction. When the first expansion body 2 is inserted into the slip 1, the first limiting strip can be aligned with the first limiting groove so that the first limiting strip is inserted into the first limiting groove. Through the mutual cooperation of the first limiting strip and the first limiting groove, the relative rotation of the first expansion body and the slip 1 can be limited, thereby improving reliability.

[0055] Furthermore, the inner surface of the tooth plate 11 is provided with a second limiting groove, and the outer surface of the second expansion plate is provided with a second limiting strip. The second limiting groove can guide the second limiting strip to move axially. The second limiting groove extends axially, and the second limiting strip also extends approximately axially. Of course, their extension direction is at a certain angle to the axial direction. When the second expansion body 3 is inserted into the slip 1, the second limiting strip can be aligned with the second limiting groove so that the second limiting strip is inserted into the second limiting groove. Through the mutual cooperation of the second limiting strip and the second limiting groove, the relative rotation of the second expansion body and the slip 1 can be limited, thereby improving reliability.

[0056] A ball pitching seat is provided at the upper end of the first tube portion 4. The ball pitching seat can carry a ball thrown into it to achieve corresponding operations.

[0057] In some embodiments, the first pipe portion 4 includes a first reducer 42 and a first circular pipe 41 connected to the larger end of the first reducer 42. The second pipe portion 5 includes a second reducer 52 and a second circular pipe 51 connected to the larger end of the second reducer 52. The pitching seat described above can be placed in the first circular pipe 41. The first circular pipe 41 can be connected to other pipes, and the second circular pipe 51 can be connected to other pipes.

[0058] Regarding the overall structure of the bridge plug, the cava teeth (roughly cylindrical) on the outer surface of the tooth plate 11 are made of ceramic or alloy and are insoluble structures, and the remaining structures are made of soluble materials, such as magnesium-aluminum alloy, that is, the bridge plug is basically soluble and is a soluble bridge plug.

[0059] In some embodiments, the outer diameter of the slip 1 is 60 mm. After the first expansion, the outer diameter expands to 90 mm, with an expansion rate of 50%. After the second expansion, the outer diameter expands to 114.3 mm, with an expansion rate of 40.5%. The total expansion rate is 85.7%.

[0060] Example 2

[0061] Referring to Figures 1 to 6, the present solution provides a bridge plug, wherein the bridge plug includes a cava 1, a first expansion body 2 having a tapered first outer peripheral surface, a second expansion body 3 having a tapered second outer peripheral surface, a first pipe portion 4 having a tapered third outer peripheral surface, and a second pipe portion 5 having a tapered fourth outer peripheral surface. The bridge plug can be configured as follows: the first expansion body 2 is inserted into the upper end of the cava 1, and the second expansion body 3 is inserted into the lower end of the cava 1, so that the first outer peripheral surface and the second outer peripheral surface can squeeze the cava 1 so that the cava 1 undergoes a first radial expansion; the first pipe portion 4 is inserted into the first expansion body 2 and the second pipe portion 5 is inserted into the second expansion body 3, so that the first expansion body 2 and the second expansion body 3 can expand radially respectively, so that the cava 1 undergoes a second radial expansion.

[0062] The first expansion body 2 and the second expansion body 3 can be of similar or identical structure, and are respectively formed into a tubular shape and have a tapered outer peripheral surface. The outer diameter of the small end of the first expansion body 2 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the first expansion body 2 is larger than the inner diameter of the slip 1. The outer diameter of the small end of the second expansion body 3 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the second expansion body 3 is larger than the inner diameter of the slip 1. Therefore, when the first expansion body 2 is inserted into the upper end of the slip 1 through its small end, a radially outward force can be applied to the inner peripheral surface of the slip 1 through the first outer peripheral surface of the first expansion body 2, so that the slip 1 expands radially outward. Similarly, when the second expansion body 3 is inserted into the lower end of the slip 1 through its small end, the slip 1 also expands radially outward. That is to say, by inserting the first expansion body 2 and the second expansion body 3 into the two ends of the slip 1 respectively, the overall radial expansion of the slip 1 can be achieved.

[0063] The first tube portion 4 has a tapered outer circumferential surface, the second tube portion 5 has a tapered outer circumferential surface, the outer diameter of the small end of the first tube portion 4 is smaller than the inner diameter of the large end of the first expansion body 2, the outer diameter of the large end of the first tube portion 4 is larger than the inner diameter of the large end of the first expansion body 2, the outer diameter of the small end of the second tube portion 5 is smaller than the inner diameter of the large end of the second expansion body 3, and the outer diameter of the large end of the second tube portion 5 is larger than the inner diameter of the large end of the second expansion body 3. Correspondingly, in the process of inserting the small end of the first tube part 4 into the large end of the first expansion body 2, the first tube part 4 applies a radially outward extrusion force to the first expansion body 2, so that the first expansion body 2 expands radially outward, and the radial expansion of the first expansion body 2 causes the cava 1 to expand radially again; similarly, in the process of inserting the small end of the second tube part 5 into the large end of the second expansion body 3, the second tube part 5 applies a radially outward extrusion force to the second expansion body 3, so that the second expansion body 3 expands radially outward, and the radial expansion of the second expansion body 3 causes the cava 1 to expand radially again. Therefore, the second radial expansion of the cava 1 can be achieved through the radial expansion of the first expansion body 2 and the second expansion body 3.

[0064] In this solution, the two expansion bodies can achieve one expansion by squeezing the slips through the tapered outer surface, and achieve another expansion of the slips through the expansion of the two expansion bodies themselves, thereby achieving two expansions of the slips, improving the expansion rate of the slips, and realizing extreme casing change sealing operations.

[0065] Furthermore, the bridge plug can be configured as follows: the first pipe portion 4 pushes the first expansion body 2 to gradually insert into the upper end of the slip 1, while the second pipe portion 5 pushes the second expansion body 3 to gradually insert into the lower end of the slip 1, so that the slip 1 first undergoes the first radial expansion and then the second radial expansion. That is, the insertion of the first expansion body 2 into the slip 1 is achieved by the push of the first pipe portion 4, and the insertion of the second expansion body 3 into the lower end of the slip 1 is achieved by the push of the second pipe portion 5. It is only necessary to insert the first pipe portion 4 into the first expansion body 2 and the second expansion body 2 into the slip 1, and then push the first pipe portion 4. On the other hand, insert the second pipe portion 5 into the second expansion body 3 and the second expansion body 3 into the slip 1, and then push the second pipe portion 5, so that the two expansions of the slip 1 can be achieved in sequence. Of course, in other embodiments, the two expansion bodies can be inserted into the slip 1 respectively to achieve the first expansion, and then the two pipe portions can be inserted respectively to achieve the second expansion of the slip 1.

[0066] In addition, the force required for the radial expansion of the first expansion body 2 and the force required for the radial expansion of the second expansion body 3 are respectively greater than the force required for the radial expansion of the slip 1. The extrusion force required for the slip 1 to begin expanding is less than the extrusion force required for the expansion of the first expansion body 2 and the extrusion force required for the expansion of the second expansion body 3. When the first tube 4 is inserted into the first expansion body 2 and the second expansion body 2 is inserted into the slip 1, the force exerted by the first tube 4 on the second expansion body 2 is transmitted to the slip 1. Therefore, the slip 1 will first begin to expand. As the first tube 4 is gradually inserted into the second expansion body 2, its extrusion force increases. When the force required for the expansion of the first expansion body 2 is reached, the second expansion body 2 begins to expand. In other words, as the first tube 4 is gradually inserted into the first expansion body 2, the second expansion body 2 is also gradually inserted into the slip 1, first achieving the first radial expansion of the slip 1, and then achieving the second radial expansion of the slip 1 through the expansion of the second expansion body 2. The second expansion body 3 and the second tube 5 are also similarly configured and will not be repeated here.

[0067] The first expansion body 2 includes a tapered first main body portion 22 and a first support ring 21 connected to the large end of the first main body portion 22. The second expansion body 3 includes a tapered second main body portion 32 and a second support ring 31 connected to the large end of the second main body portion 32. The small end of the first main body portion 22 is used to be inserted into the upper end of the slip 1, and the small end of the second main body portion 32 is used to be inserted into the lower end of the slip 1. The first support ring 21 is connected to the large end of the first main body portion 22 and can allow the first pipe portion 4 to be inserted. The second support ring 31 is connected to the large end of the second main body portion 32 and can allow the second pipe portion 5 to be inserted.

[0068] Furthermore, the force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1, and the force required for the second support ring 31 to break is greater than the force required for the radial expansion of the slip 1. The first support ring 21 is configured as a structure that limits the expansion of the first expansion body 2, that is, the first support ring 21 needs to be broken first, and the extrusion force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1. Therefore, in the process of inserting the first expansion body 2 into the first tube 4 and the second expansion body 2 into the slip 1, the slip 1 begins to expand first, and then the first tube 4 squeezes the first support ring 21 to break, and the first main body 22 begins to expand, so as to act on the slip 1 to achieve its second radial expansion. The second expansion body 3 and the second tube 5 are also configured similarly and will not be repeated here.

[0069] The first main body 22 includes a plurality of circumferentially arranged first expansion plates, and the second main body 32 includes a plurality of circumferentially arranged second expansion plates. The first expansion plates are circumferentially arranged, and when the first expansion body 2 radially expands, the circumferential spacing between adjacent first expansion plates increases, thereby enabling expansion and deployment of the first main body 22. Similarly, the second expansion plates are circumferentially arranged, and when the second expansion body 3 radially expands, the circumferential spacing between adjacent second expansion plates increases, thereby enabling expansion and deployment of the second main body 32.

[0070] The first expansion plate is integrally connected to the first support ring 21, and the second expansion plate is integrally connected to the second support ring 31. The plurality of first expansion plates and the first support ring 21 are integrally connected to form a whole. When the first support ring 21 is broken into a plurality of circumferentially arranged parts, the plurality of first expansion plates can be allowed to expand away from each other. Similarly, the plurality of second expansion plates and the second support ring 31 are integrally connected to form a whole. When the second support ring 31 is broken into a plurality of circumferentially arranged parts, the plurality of second expansion plates can be allowed to expand away from each other. Furthermore, the first support ring 21 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of first expansion plates. The second support ring 31 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of second expansion plates.

[0071] The slips 1 include multiple tooth plates 11 arranged circumferentially. During expansion, the circumferential spacing between the tooth plates 11 increases, enabling radial expansion. Slip teeth can be provided on the outer surfaces of the tooth plates 11, allowing them to engage with the inner circumferential surface of the sleeve.

[0072] In addition, the slips 1 include sealing rings 12 connected to both ends of the tooth plate 11. The sealing rings 12 are made of a sealing material, which can be a plastic material or an elastic material. When the tooth plate 11 expands and expands, the sealing rings 12 also expand, and the outer circumference of the sealing ring 12 can fit the inner circumference of the casing to form a seal.

[0073] Furthermore, the number of tooth plates 11, the number of first expansion plates, and the number of second expansion plates are the same. The first expansion plates can correspond one to each tooth plate 11, and the second expansion plates can correspond one to each tooth plate 11, i.e., radially aligned, facilitating synchronous radial outward expansion and reducing circumferential relative displacement between the first and second expansion plates and the tooth plates 11. The number of tooth plates 11, the number of first expansion plates, and the number of second expansion plates can each be seven.

[0074] Furthermore, the inner surface of the tooth plate 11 is provided with a first limiting groove, and the outer surface of the first expansion plate is provided with a first limiting strip. The first limiting groove can respectively guide the first limiting strip to move axially. The first limiting groove extends axially, and the first limiting strip also extends roughly axially. Of course, there is a certain angle between the extension direction and the axial direction. When the first expansion body 2 is inserted into the slip 1, the first limiting strip can be aligned with the first limiting groove so that the first limiting strip is inserted into the first limiting groove. Through the mutual cooperation of the first limiting strip and the first limiting groove, the relative rotation of the first expansion body and the slip 1 can be limited, thereby improving reliability.

[0075] Furthermore, the inner surface of the tooth plate 11 is provided with a second limiting groove, and the outer surface of the second expansion plate is provided with a second limiting strip. The second limiting groove can guide the second limiting strip to move axially. The second limiting groove extends axially, and the second limiting strip also extends approximately axially. Of course, their extension direction is at a certain angle to the axial direction. When the second expansion body 3 is inserted into the slip 1, the second limiting strip can be aligned with the second limiting groove so that the second limiting strip is inserted into the second limiting groove. Through the mutual cooperation of the second limiting strip and the second limiting groove, the relative rotation of the second expansion body and the slip 1 can be limited, thereby improving reliability.

[0076] A ball pitching seat is provided at the upper end of the first tube portion 4. The ball pitching seat can carry a ball thrown into it to achieve corresponding operations.

[0077] In some embodiments, the first pipe portion 4 includes a first reducer 42 and a first circular pipe 41 connected to the larger end of the first reducer 42. The second pipe portion 5 includes a second reducer 52 and a second circular pipe 51 connected to the larger end of the second reducer 52. The pitching seat described above can be placed in the first circular pipe 41. The first circular pipe 41 can be connected to other pipes, and the second circular pipe 51 can be connected to other pipes.

[0078] Regarding the overall structure of the bridge plug, the cava teeth (roughly cylindrical) on the outer surface of the tooth plate 11 are made of ceramic or alloy and are insoluble structures, and the remaining structures are made of soluble materials, such as magnesium-aluminum alloy, that is, the bridge plug is basically soluble and is a soluble bridge plug.

[0079] In some embodiments, the outer diameter of the slip 1 is 60 mm. After the first expansion, the outer diameter expands to 90 mm, with an expansion rate of 50%. After the second expansion, the outer diameter expands to 114.3 mm, with an expansion rate of 40.5%. The total expansion rate is 85.7%.

[0080] Example 3

[0081] Referring to Figures 1 to 6, the present solution provides a bridge plug, wherein the bridge plug includes a cava 1, a first expansion body 2 having a tapered first outer peripheral surface, a second expansion body 3 having a tapered second outer peripheral surface, a first pipe portion 4 having a tapered third outer peripheral surface, and a second pipe portion 5 having a tapered fourth outer peripheral surface. The bridge plug can be configured as follows: the first expansion body 2 is inserted into the upper end of the cava 1, and the second expansion body 3 is inserted into the lower end of the cava 1, so that the first outer peripheral surface and the second outer peripheral surface can squeeze the cava 1 so that the cava 1 undergoes a first radial expansion; the first pipe portion 4 is inserted into the first expansion body 2 and the second pipe portion 5 is inserted into the second expansion body 3, so that the first expansion body 2 and the second expansion body 3 can expand radially respectively, so that the cava 1 undergoes a second radial expansion.

[0082] The first expansion body 2 and the second expansion body 3 can be of similar or identical structure, and are respectively formed into a tubular shape and have a tapered outer peripheral surface. The outer diameter of the small end of the first expansion body 2 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the first expansion body 2 is larger than the inner diameter of the slip 1. The outer diameter of the small end of the second expansion body 3 is smaller than the inner diameter of the slip 1, and the outer diameter of the large end of the second expansion body 3 is larger than the inner diameter of the slip 1. Therefore, when the first expansion body 2 is inserted into the upper end of the slip 1 through its small end, a radially outward force can be applied to the inner peripheral surface of the slip 1 through the first outer peripheral surface of the first expansion body 2, so that the slip 1 expands radially outward. Similarly, when the second expansion body 3 is inserted into the lower end of the slip 1 through its small end, the slip 1 also expands radially outward. That is to say, by inserting the first expansion body 2 and the second expansion body 3 into the two ends of the slip 1 respectively, the overall radial expansion of the slip 1 can be achieved.

[0083] The first tube portion 4 has a tapered outer circumferential surface, the second tube portion 5 has a tapered outer circumferential surface, the outer diameter of the small end of the first tube portion 4 is smaller than the inner diameter of the large end of the first expansion body 2, the outer diameter of the large end of the first tube portion 4 is larger than the inner diameter of the large end of the first expansion body 2, the outer diameter of the small end of the second tube portion 5 is smaller than the inner diameter of the large end of the second expansion body 3, and the outer diameter of the large end of the second tube portion 5 is larger than the inner diameter of the large end of the second expansion body 3. Correspondingly, in the process of inserting the small end of the first tube part 4 into the large end of the first expansion body 2, the first tube part 4 applies a radially outward extrusion force to the first expansion body 2, so that the first expansion body 2 expands radially outward, and the radial expansion of the first expansion body 2 causes the cava 1 to expand radially again; similarly, in the process of inserting the small end of the second tube part 5 into the large end of the second expansion body 3, the second tube part 5 applies a radially outward extrusion force to the second expansion body 3, so that the second expansion body 3 expands radially outward, and the radial expansion of the second expansion body 3 causes the cava 1 to expand radially again. Therefore, the second radial expansion of the cava 1 can be achieved through the radial expansion of the first expansion body 2 and the second expansion body 3.

[0084] In this solution, the two expansion bodies can achieve one expansion by squeezing the slips through the tapered outer surface, and achieve another expansion of the slips through the expansion of the two expansion bodies themselves, thereby achieving two expansions of the slips, improving the expansion rate of the slips, and realizing extreme casing change sealing operations.

[0085] Furthermore, the bridge plug can be configured as follows: the first pipe portion 4 pushes the first expansion body 2 to gradually insert into the upper end of the slip 1, while the second pipe portion 5 pushes the second expansion body 3 to gradually insert into the lower end of the slip 1, so that the slip 1 first undergoes the first radial expansion and then the second radial expansion. That is, the insertion of the first expansion body 2 into the slip 1 is achieved by the push of the first pipe portion 4, and the insertion of the second expansion body 3 into the lower end of the slip 1 is achieved by the push of the second pipe portion 5. It is only necessary to insert the first pipe portion 4 into the first expansion body 2 and the second expansion body 2 into the slip 1, and then push the first pipe portion 4. On the other hand, insert the second pipe portion 5 into the second expansion body 3 and the second expansion body 3 into the slip 1, and then push the second pipe portion 5, so that the two expansions of the slip 1 can be achieved in sequence. Of course, in other embodiments, the two expansion bodies can be inserted into the slip 1 respectively to achieve the first expansion, and then the two pipe portions can be inserted respectively to achieve the second expansion of the slip 1.

[0086] In addition, the force required for the radial expansion of the first expansion body 2 and the force required for the radial expansion of the second expansion body 3 are respectively greater than the force required for the radial expansion of the slip 1. The extrusion force required for the slip 1 to begin expanding is less than the extrusion force required for the expansion of the first expansion body 2 and the extrusion force required for the expansion of the second expansion body 3. When the first tube 4 is inserted into the first expansion body 2 and the second expansion body 2 is inserted into the slip 1, the force exerted by the first tube 4 on the second expansion body 2 is transmitted to the slip 1. Therefore, the slip 1 will first begin to expand. As the first tube 4 is gradually inserted into the second expansion body 2, its extrusion force increases. When the force required for the expansion of the first expansion body 2 is reached, the second expansion body 2 begins to expand. In other words, as the first tube 4 is gradually inserted into the first expansion body 2, the second expansion body 2 is also gradually inserted into the slip 1, first achieving the first radial expansion of the slip 1, and then achieving the second radial expansion of the slip 1 through the expansion of the second expansion body 2. The second expansion body 3 and the second tube 5 are also similarly configured and will not be repeated here.

[0087] The first expansion body 2 includes a tapered first main body portion 22 and a first support ring 21 connected to the large end of the first main body portion 22. The second expansion body 3 includes a tapered second main body portion 32 and a second support ring 31 connected to the large end of the second main body portion 32. The small end of the first main body portion 22 is used to be inserted into the upper end of the slip 1, and the small end of the second main body portion 32 is used to be inserted into the lower end of the slip 1. The first support ring 21 is connected to the large end of the first main body portion 22 and can allow the first pipe portion 4 to be inserted. The second support ring 31 is connected to the large end of the second main body portion 32 and can allow the second pipe portion 5 to be inserted.

[0088] Furthermore, the force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1, and the force required for the second support ring 31 to break is greater than the force required for the radial expansion of the slip 1. The first support ring 21 is configured as a structure that limits the expansion of the first expansion body 2, that is, the first support ring 21 needs to be broken first, and the extrusion force required for the first support ring 21 to break is greater than the force required for the radial expansion of the slip 1. Therefore, in the process of inserting the first expansion body 2 into the first tube 4 and the second expansion body 2 into the slip 1, the slip 1 begins to expand first, and then the first tube 4 squeezes the first support ring 21 to break, and the first main body 22 begins to expand, so as to act on the slip 1 to achieve its second radial expansion. The second expansion body 3 and the second tube 5 are also configured similarly and will not be repeated here.

[0089] The first main body 22 includes a plurality of circumferentially arranged first expansion plates, and the second main body 32 includes a plurality of circumferentially arranged second expansion plates. The first expansion plates are circumferentially arranged, and when the first expansion body 2 radially expands, the circumferential spacing between adjacent first expansion plates increases, thereby enabling expansion and deployment of the first main body 22. Similarly, the second expansion plates are circumferentially arranged, and when the second expansion body 3 radially expands, the circumferential spacing between adjacent second expansion plates increases, thereby enabling expansion and deployment of the second main body 32.

[0090] The first expansion plate is integrally connected to the first support ring 21, and the second expansion plate is integrally connected to the second support ring 31. The plurality of first expansion plates and the first support ring 21 are integrally connected to form a whole. When the first support ring 21 is broken into a plurality of circumferentially arranged parts, the plurality of first expansion plates can be allowed to expand away from each other. Similarly, the plurality of second expansion plates and the second support ring 31 are integrally connected to form a whole. When the second support ring 31 is broken into a plurality of circumferentially arranged parts, the plurality of second expansion plates can be allowed to expand away from each other. Furthermore, the first support ring 21 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of first expansion plates. The second support ring 31 can be provided with a plurality of pre-breaking points so that it can be broken into a plurality of parts corresponding to the plurality of second expansion plates.

[0091] The slips 1 include multiple tooth plates 11 arranged circumferentially. During expansion, the circumferential spacing between the tooth plates 11 increases, enabling radial expansion. Slip teeth can be provided on the outer surfaces of the tooth plates 11, allowing them to engage with the inner circumferential surface of the sleeve.

[0092] In addition, the slips 1 include sealing rings 12 connected to both ends of the tooth plate 11. The sealing rings 12 are made of a sealing material, which can be a plastic material or an elastic material. When the tooth plate 11 expands and unfolds, the sealing rings 12 also expand, and the outer circumference of the sealing ring 12 can fit the inner circumference of the casing to form a seal.

[0093] Furthermore, the number of tooth plates 11, the number of first expansion plates, and the number of second expansion plates are the same. The first expansion plates can correspond one to one with the tooth plates 11, and the second expansion plates can correspond one to one with the tooth plates 11, i.e., radially aligned, facilitating synchronous radial outward expansion and reducing circumferential relative displacement between the first and second expansion plates and the tooth plates 11. The number of tooth plates 11, first expansion plates, and second expansion plates can each be eight.

[0094] Furthermore, the inner surface of the tooth plate 11 is provided with a first limiting groove, and the outer surface of the first expansion plate is provided with a first limiting strip. The first limiting groove can respectively guide the first limiting strip to move axially. The first limiting groove extends axially, and the first limiting strip also extends roughly axially. Of course, there is a certain angle between the extension direction and the axial direction. When the first expansion body 2 is inserted into the slip 1, the first limiting strip can be aligned with the first limiting groove so that the first limiting strip is inserted into the first limiting groove. Through the mutual cooperation of the first limiting strip and the first limiting groove, the relative rotation of the first expansion body and the slip 1 can be limited, thereby improving reliability.

[0095] Furthermore, the inner surface of the tooth plate 11 is provided with a second limiting groove, and the outer surface of the second expansion plate is provided with a second limiting strip. The second limiting groove can guide the second limiting strip to move axially. The second limiting groove extends axially, and the second limiting strip also extends approximately axially. Of course, their extension direction is at a certain angle to the axial direction. When the second expansion body 3 is inserted into the slip 1, the second limiting strip can be aligned with the second limiting groove so that the second limiting strip is inserted into the second limiting groove. Through the mutual cooperation of the second limiting strip and the second limiting groove, the relative rotation of the second expansion body and the slip 1 can be limited, thereby improving reliability.

[0096] A ball pitching seat is provided at the upper end of the first tube portion 4. The ball pitching seat can carry a ball thrown into it to achieve corresponding operations.

[0097] In some embodiments, the first pipe portion 4 includes a first reducer 42 and a first circular pipe 41 connected to the larger end of the first reducer 42. The second pipe portion 5 includes a second reducer 52 and a second circular pipe 51 connected to the larger end of the second reducer 52. The pitching seat described above can be placed in the first circular pipe 41. The first circular pipe 41 can be connected to other pipes, and the second circular pipe 51 can be connected to other pipes.

[0098] Regarding the overall structure of the bridge plug, the cava teeth (roughly cylindrical) on the outer surface of the tooth plate 11 are made of ceramic or alloy and are insoluble structures, and the remaining structures are made of soluble materials, such as magnesium-aluminum alloy, that is, the bridge plug is basically soluble and is a soluble bridge plug.

[0099] In some embodiments, the outer diameter of the slip 1 is 60 mm. After the first expansion, the outer diameter expands to 90 mm, with an expansion rate of 50%. After the second expansion, the outer diameter expands to 114.3 mm, with an expansion rate of 40.5%. The total expansion rate is 85.7%.

[0100] In addition, this solution also provides a production string, wherein, as shown in FIG7 , the production string sequentially connects a continuous oil pipe 6, a setting tool 8, a center rod 9, and a bridge plug arranged on the center rod 9, and the bridge plug is the bridge plug described in the above solution.

[0101] In some embodiments, the operation process of the production string is:

[0102] First, the bridge plug, the center rod 9, the setting tool 7 and the coiled tubing 6 are connected in sequence and lowered to the designed position, as shown in Figures 7 and 8; pressure is applied to the setting tool 7 through the wellhead to compress the first expansion body 2 and the second expansion body 3 to expand, so that the slips 1 undergo two radial expansions to achieve setting and sealing, as shown in Figure 9; then the coiled tubing 6 is lifted to drive the center rod 9 and the setting tool 7 to separate from the bridge plug and lift them to the wellhead for removal; then the sealing soluble ball 10 is pumped to seal the sealing soluble ball 10 with the first expansion body 2, as shown in Figure 10; finally, the wellhead pump pressure is lifted to perform fracturing construction to obtain a new fracturing crack 11, as shown in Figure 11.

[0103] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, the technical solution of the present invention may be subjected to a variety of simple modifications, including combining the various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A bridge plug, characterized in that: The bridge plug comprises a slip (1), a first expansion body (2) having a first tapered outer peripheral surface, a second expansion body (3) having a second tapered outer peripheral surface, a first pipe portion (4) having a third tapered outer peripheral surface, and a second pipe portion (5) having a fourth tapered outer peripheral surface. The bridge plug can be configured as follows: the first expansion body (2) is inserted into the upper end of the slip (1), and the second expansion body (3) is inserted into the lower end of the slip (1), so that the first outer peripheral surface and the second outer peripheral surface can squeeze the slip (1) to cause the slip (1) to expand radially for the first time; the first pipe portion (4) is inserted into the first expansion body (2) and the second pipe portion (5) is inserted into the second expansion body (3), so that the first expansion body (2) and the second expansion body (3) can expand radially respectively, so that the slip (1) can expand radially for the second time; The bridge plug can be configured such that: the first pipe portion (4) pushes the first expansion body (2) to gradually insert into the upper end of the slip (1), and at the same time, the second pipe portion (5) pushes the second expansion body (3) to gradually insert into the lower end of the slip (1), so that the slip (1) first performs the first radial expansion and then performs the second radial expansion; The force required for radial expansion of the first expansion body (2) and the force required for radial expansion of the second expansion body (3) are respectively greater than the force required for radial expansion of the slip (1).

2. The bridge plug according to claim 1, characterized in that: The first expansion body (2) comprises a tapered first main body portion (22) and a first support ring (21) connected to the large end of the first main body portion (22), and the second expansion body (3) comprises a tapered second main body portion (32) and a second support ring (31) connected to the large end of the second main body portion (32).

3. The bridge plug according to claim 2, characterized in that: The force required for the first support ring (21) to break is greater than the force required for the slip (1) to expand radially, and the force required for the second support ring (31) to break is greater than the force required for the slip (1) to expand radially.

4. The bridge plug according to claim 2, characterized in that: The first main body portion (22) includes a plurality of first expansion plates arranged in a circumferential direction, and the second main body portion (32) includes a plurality of second expansion plates arranged in a circumferential direction.

5. The bridge plug according to claim 4, characterized in that: The first expansion plate is integrally connected to the first support ring (21), and the second expansion plate is integrally connected to the second support ring (31).

6. The bridge plug according to claim 5, characterized in that: The slip (1) comprises a plurality of tooth plates (11) arranged circumferentially.

7. The bridge plug according to claim 6, characterized in that: The slip (1) comprises sealing rings (12) connected to both ends of the tooth plate (11).

8. The bridge plug according to claim 7, characterized in that: The number of the tooth plates (11), the number of the first expansion plates and the number of the second expansion plates are the same.

9. The bridge plug according to claim 7, characterized in that: The inner surface of the tooth plate (11) is provided with a first limiting groove, and the outer surface of the first expansion plate is provided with a first limiting strip, and the first limiting grooves can respectively guide the first limiting strip to move axially.

10. The bridge plug according to claim 7, characterized in that The inner surface of the tooth plate (11) is provided with a second limiting groove, and the outer surface of the second expansion plate is provided with a second limiting strip, wherein the second limiting groove can guide the second limiting strip to move axially.

11. The bridge plug according to claim 1, characterized in that A ball pitching seat is provided at the upper end of the first pipe part (4).

12. The bridge plug according to claim 1, characterized in that The first pipe portion (4) comprises a first reducer (42) and a first circular pipe (41) connected to the large end of the first reducer (42), and the second pipe portion (5) comprises a second reducer (52) and a second circular pipe (51) connected to the large end of the second reducer (52).

13. A production string, characterized in that: The production tubing string comprises a coiled tubing (6), a sealing tool (8), a center rod (9) and a bridge plug arranged on the center rod (9) which are connected in sequence, and the bridge plug is the bridge plug according to any one of claims 1 to 12.

14. The production tubing string according to claim 13, characterized in that: The operation process of the production string is as follows: First, the bridge plug, the center rod (9), the sealing tool (7) and the continuous oil pipe (6) are connected in sequence and lowered to the designed position. The sealing tool (7) is pressurized through the wellhead to compress the first expansion body (2) and the second expansion body (3) to expand, so that the slip (1) undergoes two radial expansions to achieve sealing and sealing. Then, the continuous oil pipe (6) is lifted to drive the center rod (9) and the sealing tool (7) to separate from the bridge plug and lift them to the wellhead for removal. Then, a sealing soluble ball (10) is pumped to seal the sealing soluble ball (10) with the first expansion body (2). Finally, the wellhead is pumped to perform fracturing construction to obtain a new fracturing crack (11).

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