A dual-grip dissolvable bridge plug and system

Abstract

The application discloses a double-grip soluble bridge plug and system. The bridge plug comprises a core shaft, an upper grip, a cone, a sealing assembly, a lower grip and a connecting piece. The cone comprises a first cone and a second cone connected with each other. The core shaft is connected with the cone. One end of the upper grip is connected with the core shaft, and the other end of the upper grip is sleeved on the first cone. The sealing assembly is used for sealing the gap between the second cone and the inner wall of the casing. The sealing assembly and the lower grip are sequentially sleeved on the second cone. The lower grip is connected with the connecting piece. The lower grip comprises a plurality of lower grip petals. The lower grip petal comprises a main body, a boss and a groove arranged on both sides of the main body respectively. The boss and the groove between adjacent lower grip petals are adaptively arranged. In the state that the groove and the boss of the lower grip petal are matched, the lower grip petal forms an annular whole. After the bridge plug is set and sealed, the adjacent lower grip petals are staggered with each other, and the staggered distance is less than the length of the abutting surface of the adjacent lower grip petals in the circumferential direction. The sealing effect of the bridge plug can be improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling and fracturing technology, and particularly to a double slip soluble bridge plug and system. Background Technology

[0002] For the in-depth development of unconventional oil and gas resources, especially shale oil and gas, tight oil and gas, and low-permeability oil and gas, stratified injection and production, and multi-stage fracturing are among the most effective means of efficient development. Currently, over 90% of unconventional oil and gas resource development utilizes multi-stage fracturing technology combining perforation guns and bridge plugs. In this technology, the bridge plug is the core tool for effectively isolating the visual lines between different stages of fracturing. Typically, during fracturing, the bridge plug is used to seal the downhole casing and isolate the target formation. The soluble bridge plugs used in existing multi-stage fracturing technologies can completely dissolve after fracturing, relying on the wellbore temperature and salinity fluid environment, ensuring full-bore production. This approach offers advantages such as low overall cost, short commissioning time, reduced operational risks, and the ability to perform secondary fracturing.

[0003] Currently, the commonly used soluble bridge plugs are mainly the double-slip soluble rubber sleeve sealing structure bridge plug and the single-slip all-metal soluble bridge plug. The double-slip soluble rubber sleeve structure bridge plug has a complex structure, a large total length, and a small diameter. It achieves sealing by compressing the rubber sleeve, which can realize the setting and pressure bearing of large annular bushings, and the pressure bearing effect is good. The single-slip all-metal sealing structure soluble bridge plug has a simple structure. The entire structure is made of fast-dissolving magnesium alloy. It has a large diameter, dissolves quickly, and can eliminate the need for drilling. Summary of the Invention

[0004] In existing unconventional oil and gas resource extraction operations, problems such as soluble bridge plug setting and anchoring failure or abnormal sealing pressure frequently occur, leading to overall bridge plug slippage or seal failure. The inventors of this application have discovered that during construction operations, after the bridge plug is set, the slips expand and anchor to the inner wall of the casing. There is a certain gap between each slip, and this gap increases with the size of the annulus between the bridge plug and the casing inner wall. The bridge plug's sealing assembly mainly relies on the lower slip pushing and compressing the sealing assembly upwards to deform and seal the bridge plug against the casing inner wall. As the gaps between the slips gradually increase, the support strength of the lower slip for the sealing assembly weakens at these gaps. During the pressure-bearing process after bridge plug setting, the sealing assembly at these gaps undergoes significant deformation under pressure, easily causing crushing deformation. This results in poor overall bridge plug stability, leading to overall bridge plug slippage or seal failure.

[0005] In view of the above problems, the present invention is proposed to provide a dual-slip soluble bridge plug and system that overcomes or at least partially solves the above problems.

[0006] This invention provides a double-slip soluble bridge plug, comprising: a mandrel, an upper slip, a cone, a sealing assembly, a lower slip, and a connector;

[0007] The cone includes a first cone and a second cone connected together. The radial dimension at the connection between the first cone and the second cone is greater than the radial dimension at both ends, and the cone has a hollow structure.

[0008] The mandrel is connected to the inner wall of the cone, one end of the upper collet is connected to the mandrel, and the other end is provided with a first conical surface that matches the outer surface of the first cone, so as to be fitted onto the first cone;

[0009] The sealing assembly, lower slip, and connector are connected in sequence.

[0010] The sealing assembly is used to seal the gap between the second cone and the inner wall of the sleeve, and is provided with a second conical surface that matches the outer surface of the second cone, so as to be fitted onto the second cone;

[0011] The lower slip is provided with a third conical surface that matches the outer surface of the second cone, so as to be fitted onto the second cone. The lower slip includes multiple lower slip lobes.

[0012] The lower slip includes a main body, and protrusions and grooves respectively disposed on both sides of the main body, and the protrusions and grooves between adjacent lower slips are adapted to each other;

[0013] When the groove and the boss of the lower slip are fitted together, the lower slip forms an annular whole; after the bridge plug is set, the adjacent lower slips are staggered from each other, and the staggered distance is less than the length of the contact surface of the adjacent lower slips in the circumferential direction.

[0014] In an optional embodiment, the thickness of the boss of the lower slip flap is set to 4-8 mm;

[0015] The length of the protrusion of the lower clasp along the circumferential direction is set to 5-10 mm.

[0016] In an optional embodiment, the taper of the first cone is greater than the taper of the second cone;

[0017] The taper of the first cone is 10° to 30°, and the taper of the second cone is 5° to 13°.

[0018] In an optional embodiment, one end of the mandrel is provided with a conical hole for engaging with a sealing ball and a step for engaging with a seated sleeve, and the other end is provided with an annular groove, in which a locking ring is provided, and a first retaining tooth is provided on the outer surface of the locking ring.

[0019] Correspondingly, a second locking tooth is provided on the inner wall of the cone to match the first locking tooth, so as to limit the mandrel through the cooperation of the first locking tooth and the second locking tooth;

[0020] Furthermore, at least one sealing ring is provided between the mandrel and the cone.

[0021] In an optional embodiment, the first locking tooth is a sawtooth external thread; correspondingly, the second locking tooth is a sawtooth internal thread adapted to the sawtooth external thread.

[0022] In the assembled state before the bridge plug is set, the engagement length of the first locking tooth and the second locking tooth is not less than 1 / 5 of the total length of the external thread of the sawtooth.

[0023] In an optional embodiment, the sealing assembly includes: at least one support ring, a sealing body, at least one gasket ring, and a clamping ring sequentially fitted onto the second cone;

[0024] The sealing body is a soluble rubber material or a soluble metal material, used to seal the gap between the second cone and the inner wall of the sleeve;

[0025] One end of the clamping ring is provided with a stepped hole for engaging with the annular groove of the lower clamping slip to connect the clamping ring with the lower clamping slip.

[0026] In an optional embodiment, the support ring, the washer ring, and the clamping ring are provided with grooves in the axial direction, and the grooves of the support ring and the clamping ring are staggered from the grooves of the washer ring.

[0027] In an optional embodiment, the inner wall of the sealing body is provided with a compression groove.

[0028] In an optional embodiment, the support ring, sealing body, gasket ring, and clamping ring are annular structures, and the outer diameter of the sealing body is larger than the outer diameter of the support ring, the gasket ring, and the clamping ring.

[0029] In an optional embodiment, the upper slip includes a plurality of upper slip segments arranged in the circumferential direction, and the plurality of upper slip segments are clamped together into a ring by a pre-tightening ring and an anti-expansion ring; and the pre-tightening ring and the anti-expansion ring can break under a preset pressure.

[0030] In an optional embodiment, the upper slip flap is provided with a plurality of first mounting holes inclined along the direction of the first cone, and the lower slip flap is provided with a plurality of second mounting holes inclined along the direction of the second cone, wherein the first mounting holes and the second mounting holes are used to install anchor teeth.

[0031] In an optional embodiment, the lower slip includes 6 to 12 lower slip lobes.

[0032] In an optional embodiment, a third locking tooth is provided on the first conical surface of the lower slip near the end of the connector, and correspondingly, a fourth locking tooth is provided on the outer surface of the second cone to fit the third locking tooth, so as to limit the lower slip by the cooperation of the third locking tooth and the fourth locking tooth.

[0033] In an optional embodiment, a first guide protrusion is provided on the end face of the upper collet, and correspondingly, a first guide groove adapted to the first guide protrusion is provided on the spindle to circumferentially limit the upper collet.

[0034] A second guide protrusion is provided on the end face of the lower slip, and correspondingly, a second guide groove is provided on the connector to fit the second guide protrusion, so as to circumferentially limit the lower slip.

[0035] In an optional embodiment, the inner hole of the connector is provided with a release thread for connection to a release mandrel via the release thread;

[0036] Furthermore, the connector is provided with multiple set screw holes for installing set screws to circumferentially limit the release spindle.

[0037] Based on the same inventive concept, this invention also provides a double slip soluble bridge plug system, including: a setting tool and a double slip soluble bridge plug as described above;

[0038] The setting tool includes: a release mandrel and a setting sleeve;

[0039] The release mandrel and the connecting piece are connected by a release thread, and the seat sleeve abuts against the step of the mandrel. The beneficial effects of the above technical solution provided by the embodiments of the present invention include at least the following:

[0040] The double-slip soluble bridge plug provided in this invention comprises multiple lower slip segments, with adjacent lower slip segments having matching bosses and grooves. When the matching grooves and bosses of the lower slip segments are in contact, the lower slip segments form a ring-shaped whole. After the bridge plug is set, adjacent lower slip segments are staggered, and the staggered distance is less than the length of the contact surface of adjacent lower slip segments along the circumferential direction. That is, after the bridge plug is set, there is still overlap between the lower slip segments, preventing the formation of a continuous gap. This allows the sealing assembly to be supported along the entire circumference during the entire setting process, achieving a highly efficient sealing effect. It avoids the problem of sealing failure due to excessive gaps between slip segments or insufficient deformation at the gaps in the sealing assembly. Furthermore, the double-slip structure of the bridge plug enables bidirectional anchoring and locking after setting, significantly improving the anchoring stability and bidirectional pressure bearing capacity of the bridge plug, preventing slippage, movement, disintegration, or loss of seal during bottom hole pressure fluctuations.

[0041] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. The dotted lines and dashed lines in the drawings are auxiliary lines. In the drawings:

[0044] Figure 1 This is an isometric side view of the double-slip soluble bridge plug in an embodiment of the present invention;

[0045] Figure 2 This is a cross-sectional schematic diagram of the overall structure of the dual-slip soluble bridge plug in an embodiment of the present invention;

[0046] Figure 3 This is a cross-sectional schematic diagram of the conical structure of the double-slip soluble bridge plug in an embodiment of the present invention;

[0047] Figure 4 This is a right view of the lower slip flap structure of the double slip soluble bridge plug in an embodiment of the present invention;

[0048] Figure 5 This is an initial assembly diagram of the double slip soluble bridge plug slip in an embodiment of the present invention;

[0049] Figure 6This is a diagram showing the relationship after the slip is set under the soluble bridge plug of the double slip in an embodiment of the present invention;

[0050] Figure 7 This is a cross-sectional schematic diagram of the mandrel and locking ring assembly structure of the double slip soluble bridge plug in an embodiment of the present invention;

[0051] Figure 8 This is a cross-sectional schematic diagram of the sealing assembly structure of the double slip soluble bridge plug in an embodiment of the present invention;

[0052] Figure 9 This is a cross-sectional schematic diagram of the lower slip flap structure of the double slip soluble bridge plug in an embodiment of the present invention;

[0053] Figure 10 This is a partial schematic diagram of the settling of the double slip soluble bridge plug in an embodiment of the present invention.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1. Mandrel, 2. Preload ring, 3. Upper slip, 4. First anchor tooth, 5. Sealing ring, 6. Anti-expansion ring, 7. Locking ring, 8. Cone, 9. Support ring, 10. Sealing body, 11. Washer ring, 12. Hoop ring, 13. Lower slip, 14. Anchor tooth, 15. Hoop ring, 16. Connector, 17. Sealing ball;

[0056] 31-Upper locking flap, 71-First locking tooth, 81-First cone, 82-Second cone, 83-Fourth locking tooth, 84-Second locking tooth, 101-Extrusion groove, 110-First guide groove;

[0057] 131-Lower locking flap, 132-Third locking tooth, 133-Second guide boss, 1311-Main body, 1312-Boss, 1313-Groove. Detailed Implementation

[0058] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0059] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] In current unconventional oil and gas resource development operations, the commonly used soluble bridge plugs are mainly double-slip soluble glue cartridge seal structure bridge plugs and single-slip all-metal soluble bridge plugs. The existing double-slip soluble glue cartridge seal structure, due to its large cartridge volume, has a slow dissolution rate after fracturing, resulting in significant residue. This often necessitates drilling and well cleaning operations to avoid impacting flowback and production. Furthermore, as the number of stages in horizontal well fracturing increases, the number of soluble bridge plugs deployed also increases. The accumulation of dissolved glue cartridge fragments at the bottom of the well complicates well cleaning processes, increasing the operation cycle and time. Cost; while existing single-slip all-metal soluble bridge plugs have a relatively fast dissolution rate, limited effective sealing time, relatively high requirements for operating conditions, and certain deficiencies in casing applicability and pressure resistance stability; therefore, existing technologies are constantly improving bridge plug structures. For example, patent application No. 202221185404.9, entitled "A Coreless Dissolvable Double-Slip Bridge Plug", proposes a structure that combines the advantages of multiple bridge plug structure types such as double-slip soluble glue cylinder bridge plugs and single-slip all-metal soluble bridge plugs, and uses sealing components to achieve a seal between the bridge plug and the wellbore.

[0062] Regarding the existing bridge plug structure, the inventors of this application discovered that during construction, after the bridge plug is set, the slips expand and anchor to the inner wall of the casing. There is a certain gap between each slip, and the gap between the slips increases as the annulus between the bridge plug and the inner wall of the casing becomes larger. The sealing component of the bridge plug mainly relies on the lower slip to push and squeeze the sealing component upward, so that the sealing component deforms and seals the bridge plug and the inner wall of the casing. As the gap between each slip gradually increases, the support strength of the lower slip for the sealing component at the gap weakens. During the pressure process after the bridge plug is set, the sealing component at the gap will undergo large deformation under pressure, which can easily cause crushing deformation of the sealing component at the gap, resulting in poor overall stability of the bridge plug, and thus leading to overall slippage or loss of seal of the bridge plug.

[0063] To address the aforementioned problems in the prior art, this invention provides a double-slip soluble bridge plug. Based on the existing bridge plug structure, further improvements are made to the structure to solve the problem that after the lower slip flap expands and anchors to the inner wall of the casing, the gaps between the slip flaps weaken the support strength of the lower slip for the sealing assembly. This leads to increased sealing deformation at the gaps during bridge plug pressure bearing, resulting in poor overall bridge plug stability and causing problems such as soluble bridge plug setting and anchoring failure or abnormal sealing pressure bearing. It should be noted that in this invention, the end closer to the wellhead during bridge plug lowering is referred to as the "upper" end, and the end farther from the wellhead as the "lower" end.

[0064] The dual-slip soluble bridge plug provided in this embodiment of the invention refers to... Figures 1 to 5 As shown, it includes: a mandrel 1, an upper slip 2, a cone 8, a sealing assembly, a lower slip 13, and a connector 16;

[0065] The cone 8 includes a first cone 81 and a second cone 82 connected together. The radial dimension at the connection between the first cone 81 and the second cone 82 is greater than the radial dimension at both ends, and the cone 8 is a hollow structure.

[0066] The mandrel 1 is connected to the inner wall of the cone 8. One end of the upper collet 2 is connected to the mandrel 1, and the other end is provided with a first conical surface that matches the outer surface of the first cone 81, so as to be fitted onto the first cone 81.

[0067] The sealing assembly, the lower slip 13, and the connector 16 are connected in sequence.

[0068] The sealing assembly is used to seal the gap between the second cone 82 and the inner wall of the sleeve, and is provided with a second conical surface that matches the outer surface of the second cone 82 so as to be fitted onto the second cone 82;

[0069] The lower slip 13 is provided with a third conical surface that matches the outer surface of the second cone 82, so as to be fitted onto the second cone 82. The lower slip 13 includes a plurality of lower slip lobes 131.

[0070] The lower flap 131 includes a main body 1311, and protrusions 1312 and grooves 1313 respectively disposed on both sides of the main body, and the protrusions 1312 and grooves 1313 between adjacent lower flaps 131 are adapted to each other.

[0071] With the groove 1313 and the boss 1312 of the lower slip 131 in a fitted state, the lower slip 131 forms an annular whole; after the bridge plug is set, the adjacent lower slips 131 are staggered from each other, and the staggered distance is less than the length of the contact surface of the adjacent lower slips 131 in the circumferential direction.

[0072] This invention provides a soluble bridge plug structure. After the bridge plug is set, the adjacent lower slips 131 are staggered, with the stagger distance being less than the length of the contact surface of the adjacent lower slips 131 in the circumferential direction. That is, after the bridge plug is set, there is still overlap between the lower slips 131, and no gap is formed from top to bottom. It can support the sealing assembly in the entire circumferential direction during the entire setting process, achieving a highly efficient sealing effect. It will not cause sealing failure due to excessive gaps between slips and insufficient deformation at the gaps in the sealing assembly. Furthermore, the bridge plug is designed with a double slip structure, which can achieve bidirectional anchoring and locking after the bridge plug is set, significantly improving the anchoring stability and bidirectional pressure bearing capacity of the bridge plug, and preventing the bridge plug from slipping, moving, disintegrating, or losing its seal when the bottom hole pressure fluctuates.

[0073] Specifically, the length of the contact surface of adjacent lower slip flaps 131 along the circumferential direction is the length of the boss 1312 of the lower slip flap along the circumferential direction. Optionally, the thickness of the boss 1312 of the lower slip flap can be set to 4-8 mm to ensure that the boss position has sufficient strength to support the sealing assembly. The length of the boss 1312 of the lower slip flap along the circumferential direction can be set to 5-10 mm to cover the gap between the lower slip flaps when sealing sleeves of different sizes with soluble bridge plugs of different diameters. The specific selection can be made according to actual needs, and the embodiments of the present invention do not impose specific limitations on this.

[0074] The soluble bridge plug lower slip 13 of this invention has a multi-lobed structure and is generally annular; wherein, the lower slip 13 includes 6 to 12 lower slip lobes 131, which can be selected according to actual needs. For example, the lower slip 13 can adopt an 8-lobed structure.

[0075] Specifically, the inner hole at the front end of the lower slip 13 is a conical surface, i.e., the third conical surface. The taper of the third conical surface is consistent with that of the second cone 82. Furthermore, the lower slip flap 131 has an asymmetrical structure; specifically, a continuous groove can be provided on the left side, and a continuous protrusion that mates with the groove is provided on the right side. (Refer to...) Figure 5As shown, during assembly, the lower locking flaps 131 can be fitted together to form a whole. When expanding outward, the flaps open along the circumferential direction, but due to the fit of the grooves and protrusions, a "zero" gap structure is formed between the flaps. Optionally, each lower locking flap 131 can be a longitudinally continuous structure, which can be a "Z"-shaped structure with protrusions and grooves set at the radial ends of the main body 1311, or a "╩╦"-shaped structure with protrusions and grooves set at a certain middle part of the radial direction of the main body 1311. The embodiments of the present invention do not specifically limit this, as long as the protrusions and grooves of each lower locking flap 131 can be fitted together, and the flaps can be seamlessly arranged along the circumferential direction, and the flaps can form an interlaced and locked state.

[0076] Reference Figure 5 and Figure 6 The figures show the initial and post-setting relationships of the soluble bridge plug slips 13 after assembly, respectively, according to an embodiment of the present invention. As can be seen from the figures, initially, the slip segments are fitted together by the bosses 1312 and grooves 1313, forming a nearly seamless arrangement along the circumference. Furthermore, the segments form an interlocking, locked state, making them difficult to disintegrate during lowering and further preventing premature setting of the bridge plug before it reaches the predetermined position in the well. During the setting process, each slip segment needs to move simultaneously, reducing the likelihood of any slip segment failing to anchor.

[0077] In this embodiment of the invention, the cone 8 of the soluble bridge plug is equivalent to the central connector of the bridge plug and has a through-hole structure. The cone 8 has a double-cone structure, divided into a first cone 81 and a second cone 82. The taper of the first cone 81 is greater than that of the second cone 82, and the taper of the first cone can be 10° to 30°, while the taper of the second cone 82 can be 5° to 13°. Specifically, it can be selected according to actual needs; for example, the taper of the second cone can be selected as 9°. Correspondingly, the taper of the second conical surface of the sealing assembly and the third conical surface of the lower slip 13 are consistent with the taper of the second cone 82, and the taper of the first conical surface of the mandrel is consistent with the taper of the first cone. Setting the cone 8 to have a larger front end and a smaller rear end reduces the overall setting stroke while ensuring successful setting of the bridge plug.

[0078] Furthermore, refer to Figure 7 As shown, the mandrel 1 of the soluble bridge plug of the present invention has a conical hole for cooperating with the sealing ball and a step for cooperating with the seated sleeve at one end, and an annular groove at the other end. A locking ring 7 is provided in the annular groove, and a first locking tooth is provided on the outer surface of the locking ring 7.

[0079] Correspondingly, a second locking tooth 84 adapted to the first locking tooth is provided on the inner wall of the cone, so as to limit the mandrel 1 by the cooperation of the first locking tooth and the second locking tooth 84.

[0080] Furthermore, at least one sealing ring 5 is provided between the mandrel 1 and the cone 8; specifically, refer to Figure 3 As shown, a stepped hole is provided on the left side of the cone 8, which is a sealing surface that mates with the mandrel 1.

[0081] Reference Figure 7 As shown, the mandrel 1 has a tubular structure. The inner hole on the left side (i.e., the end away from the cone) of the mandrel 1 has a conical surface, which allows the sealing ball 17 to fit tightly against the conical surface to establish a seal for the bridge plug during downhole operation. The left side of the mandrel 1 may also have an anti-rotation groove, which can be used to install an anti-rotation locking ring for the bridge plug setting tool to prevent the mandrel 1 from rotating relative to the bridge plug, thus preventing setting failure.

[0082] Specifically, a step is set on the left outer circle of the mandrel 1 to cooperate and position with the setting sleeve of the setting tool, preventing axial slippage between the setting sleeve and the mandrel 1, which would affect the setting effect. A sealing ring 5 is set in a sealing groove on the outer circle of the mandrel 1 to achieve a seal between the mandrel 1 and the inner bore of the cone after the bridge plug is set. The number of sealing rings 5 ​​is not specifically limited in this embodiment of the invention; for example… Figure 1 Two sealing rings 5 ​​are provided between the cone 8 and the mandrel 1. Optionally, the annular groove is specifically provided at one end of the mandrel 1 near the second cone 82. When designing the bridge plug structure, the outer diameter of the annular groove can be slightly smaller than the outer diameter of the sealing groove. Specifically, the difference between the outer diameters of the two can be 3-15mm.

[0083] Furthermore, a locking ring 7 is installed in the annular groove of the mandrel. Specifically, the locking ring 7 can be C-shaped, with the first locking tooth 71 set on the outer circle of the locking ring 7, and a certain width of slit provided in the circumferential direction of the locking ring 7, so that it has a certain radial deformation capability, that is, it can achieve a small amount of diameter reduction or expansion.

[0084] Optionally, the first locking tooth 71 can be a special sawtooth external thread, and correspondingly, the second locking tooth 84 on the inner wall of the cone 8 is a sawtooth internal thread adapted to the sawtooth external thread. In the assembled state before the bridge plug is set, the engagement length of the first locking tooth 71 and the second locking tooth 84 is not less than 1 / 5 of the total length of the sawtooth external thread. During assembly, part of the thread of the locking ring 7 engages with the thread of the inner hole of the cone, and the engagement length exceeds 1 / 5 of the total thread length of the second locking tooth 84. Furthermore, setting the first locking tooth 71 and the second locking tooth 84 as special sawtooth threads allows the locking ring 7 to move in a jumping motion along the inner thread of the cone during the setting process, while maintaining engagement with the cone through the cooperation between the inner and outer threads. This achieves mutual locking between the mandrel 1 and the cone 8. As the locking ring 7 moves axially, its C-shaped notch tightens due to the squeezing action of the cone, preventing the locking ring 7 from disengaging from the annular groove of the mandrel 1. This reduces the possibility of the mandrel 1 disengaging and the seal failing when it is subjected to reverse impact under the pressure at the bottom of the well.

[0085] In an optional embodiment, refer to Figure 8 As shown, the sealing assembly includes: at least one support ring 9, a sealing body 10, at least one gasket 11 and a clamping ring 12 sequentially sleeved on the second cone 82; and the inner holes of each component of the support ring 9, the sealing body 10, the gasket 11 and the clamping ring 12 are all conical surfaces, that is, forming the second cone surface, and the outer circles of each component are all cylindrical surfaces.

[0086] The sealing body 10 is made of soluble rubber or soluble metal material and is used to seal the gap between the second cone 82 and the inner wall of the sleeve.

[0087] One end of the clamping ring 12 is provided with a stepped hole, which is used to mate with the annular groove of the lower slip 13 so that the clamping ring 12 is connected to the lower slip 13.

[0088] In an optional embodiment, the support ring 9, the washer ring 11, and the clamping ring 12 are provided with grooves in the axial direction, and the grooves of the support ring 9 and the clamping ring 12 are staggered from the grooves of the washer ring 11.

[0089] The grooves can be formed on the inner circumference of the support ring 9, the washer ring 11, and the clamping ring 12. The purpose of machining the grooves is to ensure that the components can be expected to break under certain strength conditions. When assembling the sealing assembly, the purpose of setting the grooves of the support ring 9 and the clamping ring 12 to be staggered from the grooves of the washer ring 11 is to allow them to overlap after the washer ring 11, the clamping ring 12, and the support ring 9 break during setting, thus preventing the formation of support gaps. The present invention does not specifically limit the angle of the stagger between the grooves of the support ring 9 and the clamping ring 12 and the grooves of the washer ring 11. Preferably, the grooves of the support ring 9 and the clamping ring 12 are in the same direction, and the grooves of the washer ring 11 and the clamping ring 12 are at 180°.

[0090] Specifically, the sealing body 10 achieves a sealing effect through deformation. The sealing body is made of soluble rubber and soluble metal, which can be soluble rubber with good elasticity, corrosion resistance, and high temperature resistance, or soluble metal material with high elongation.

[0091] Furthermore, a compression groove 101 can be provided on the inner wall of the sealing body 10. Optionally, the compression groove 101 can be located in the middle of the inner wall of the sealing body 10. The cross-section of the compression groove 101 can be trapezoidal, U-shaped, V-shaped, etc., and the sharp corner of the compression groove 101 can be rounded. When the soluble bridge plug is set, the sealing body 10 deforms continuously when the lower slip 13 compresses the gasket 11 under axial force, and expands along the conical surface of the second cone 82. Because there is a gap at the compression groove 101, the strength of the two ends of the sealing body 10 is relatively weak. The compression groove 101 deforms first, and the two sides of the compression groove 101 move closer to the middle. During the setting process, the compression groove 101 in the inner cavity of the sealing body 10 is usually squeezed and closed, so that the part of the sealing body 10 with the compression groove 101 can bulge to form a sealing band and then stick to the sleeve to form a seal. The compression groove 101 can increase the deformation range of the sealing body 10, further enhancing the sealing effect of the soluble rubber plug setting.

[0092] Reference Figure 2 and Figure 8 As shown, the support ring 9 is located on the left side of the sealing body 10 (i.e., the side closer to the first cone 81), and has an overall annular structure with an inner hole that mates with the second cone 82. Furthermore, a long, thin groove is machined on the circumference of the support ring 9 to reduce the fracture area, ensuring that the support ring 9 can break under a certain degree of pressure. The support ring 9 also provides support to the sealing body 10 during the setting process, improving the sealing body 10's pressure resistance, and can further deform the sealing body 10 to achieve a better sealing effect. (Refer to...) Figure 1 As shown, in this embodiment of the invention, the soluble bridge plug structure support ring 9 is set to one. Optionally, in practical applications, the structure of the support ring 9 can be set to multiple support rings 9 overlapping each other according to the pressure bearing capacity requirements. The number can be 1 to 4. When setting the support ring, attention should be paid to the layout of the groove direction. The grooves of two adjacent support rings should be staggered. Preferably, the staggered angle can be 180°. Furthermore, two adjacent support rings 9 can be glued together to prevent directional rotation during storage, transportation, and placement.

[0093] The gasket 11 and clamping ring 12 are located on the right side of the sealing body 10 (i.e. the side away from the first cone 81), and also serve as supports. When pressure is applied to the sealing body 10 through the support ring 9, if the rear end of the sealing body 10 is not supported, it cannot achieve sufficient deformation, which may also lead to the failure of the bridge plug to set.

[0094] Specifically, the gasket 11 is located on the right side of the sealing body 10, and is also generally ring-shaped, with an inner hole that mates with the conical surface of the second cone 82. Furthermore, the circumference of the gasket 11 is machined with long, thin grooves to reduce the fracture area, ensuring that the gasket 11 can break under a certain degree of pressure. When the sealing body 10 is compressed, the gasket 11 acts as a rear support. The cooperation between the gasket 11 and the support ring 9 allows for the overall deformation of the sealing body 10, preventing insufficient compression strength and small deformation due to gaps, thus avoiding failure to achieve the pre-sealing purpose. (Refer to...) Figure 1 As shown, in this embodiment of the invention, the soluble bridge plug structure has one gasket 11. Optionally, in practical applications, multiple gaskets 11 can be stacked according to the pressure-bearing capacity requirements, with the number ranging from 1 to 6. When setting the gaskets, attention should also be paid to the layout of the groove direction. The grooves of adjacent gaskets 11 should be staggered, preferably at an angle of 180°. Furthermore, adjacent gaskets 11 can be bonded together to prevent rotation during storage, transportation, and placement.

[0095] The clamping ring 12 is located to the right of the washer ring 11 and has an overall annular structure. A long, narrow groove is machined on the inner circumference of the clamping ring 12 to reduce the fracture area and ensure that the clamping ring 12 can break under a certain degree of pressure. During assembly, the grooves of the washer ring 11 and the clamping ring 12 can be staggered by 180°. During setting, after the two pieces break, they can overlap, preventing the formation of a support gap for the sealing body 10.

[0096] Furthermore, the stepped hole is set on the end face of the clamping ring 12 near the lower slip 13, and cooperates with the annular groove set on the front of the lower slip 13. Together with the clamping ring 15 on the rear side of the lower slip 13, it can clamp the lower slip 13 into a whole, ensuring the smooth progress of the soluble bridge plug lowering process and preventing the soluble bridge plug from setting prematurely.

[0097] In an optional embodiment, the outer diameter of the sealing body 10 in the sealing assembly is larger than the outer diameters of the support ring 9, the gasket 11, and the clamping ring 12, to ensure that the sealing body 10 has a sufficiently large compression to achieve the initial seal of the bridge plug. Optionally, during the design, the outer diameters of the support ring, gasket, and clamping ring can be set to the same value or different values. When they are the same value, the difference between the outer diameter of the sealing body 10 and this value can be 0.5 to 3 mm; when they are different values, the difference between the outer diameter of the sealing body 10 and the maximum value is 0.5 to 3 mm. The specific structural design of this embodiment is not specifically limited and can be selected according to actual needs.

[0098] Optionally, the upper slip 3 in this embodiment of the invention includes a plurality of upper slip segments 31 arranged in the circumferential direction. The plurality of upper slip segments 31 are clamped together into a ring by a locking ring 2 and an anti-expansion ring 6; and the locking ring 2 and the anti-expansion ring 6 can break under a preset pressure.

[0099] The upper slip 3 can be a segmented structure, typically with 6 to 12 segments. When the segments of the upper slip 3 are combined, they form a ring-like structure. The multiple segments of the upper slip 3 can be evenly distributed circumferentially. The inner hole of the upper slip 3 sits on the outer circle of the mandrel 1, and the inner side of the rear end of the upper slip 3 is a conical surface, which is the first conical surface that matches the first cone 81. Optionally, the specific structure of the upper slip segment 31 can be the same as that of the lower slip segment 131, or it can be the same as the existing upper slip segment 31. This embodiment of the invention does not specifically limit this.

[0100] Furthermore, refer to Figure 2 As shown, the front and rear ends of the upper slip 3 can be machined with annular grooves, which are used to assemble the locking ring 2 and the anti-expansion ring 6 respectively. Specifically, the locking ring 2 and the anti-expansion ring 6 can be set on the front and rear sides of the upper slip 3.

[0101] The anti-expansion ring 6 and locking ring 2 are annular structures. The anti-expansion ring 6 is located at the rightmost end of the upper slip 3. The cross-section of the anti-expansion ring 6 can be L-shaped, and its inner surface can be machined with a small U-shaped groove. The fracture strength of the locking ring 2 and the anti-expansion ring 6 can be determined by calculating their cross-sectional area. In the initial state before the bridge plug is set, the locking ring 2 and the anti-expansion ring 6 are used to tighten the upper slip 3 into a whole, ensuring that the locking ring 2 and the anti-expansion ring 6 only break under pressure exceeding their fracture strength. This prevents the upper slip 3 from disintegrating or expanding prematurely, which could lead to premature or abnormal setting of the bridge plug, while also ensuring normal setting of the bridge plug. After the anti-expansion ring 6 breaks and forms a C-shape, it continues to expand along the large end of the cone surface of the upper slip 3 to a certain position without freely detaching, thus avoiding affecting the setting effect of the bridge plug.

[0102] Furthermore, the upper slip 31 is provided with a plurality of first mounting holes inclined along the direction of the first cone 81, and the lower slip 131 is provided with a plurality of second mounting holes inclined along the direction of the second cone 82. The first mounting holes and the second mounting holes are used to install the anchor teeth. Each upper slip 3 and lower slip has a first mounting hole with a certain angle on its outer circumference. Specifically, the first mounting hole can be a cylindrical blind hole. The tilt angle of the cylindrical blind hole on the upper slip 31 is generally rotated 10°-20° clockwise to be used to insert the first anchor tooth 4. Under the action of axial sealing force, the upper slip 3 gradually expands outward and contacts the sleeve, and is then fixed to the sleeve by the first anchor tooth 4, locking the front end position of the bridge plug and preventing axial slippage of the bridge plug. The tilt angle of the cylindrical blind hole on the lower slip 131 is tilted counterclockwise to be used to insert the second anchor tooth 14. Under the action of axial sealing force, the lower slip 13 gradually expands outward and contacts the sleeve, and is then fixed to the sleeve by the second anchor tooth 14, locking the rear end position of the bridge plug.

[0103] Specifically, the anchor teeth have a cylindrical structure, and their main function is to gradually bite into the inner wall of the sleeve under axial force, achieving firm anchoring of the slips and providing a certain anchoring strength. Optionally, the diameter of the anchor teeth is generally 5–12 mm; for example, in application, anchor teeth with a diameter of 9 mm can be selected. Furthermore, the number of anchor teeth on each upper slip 3 or lower slip 13 can be selected from 2 to 6. For example, refer to… Figure 1 As shown, each upper jaw 3 is provided with two first anchor teeth 4, and each lower jaw 13 is provided with three second anchor teeth 14. Furthermore, the anchor teeth can be made of materials with certain hardness and strength, such as ceramics or alloys. Regarding the distribution of the anchor teeth on the upper jaw 3 or lower jaw 13, they can be distributed on the outer surface of the jaw block in triangular, rectangular, or rhomboid patterns, depending on the selected number of anchor teeth. Specifically, the specific number, material, and distribution of the anchor teeth are not specifically limited in this embodiment and can be selected according to actual needs.

[0104] In an optional embodiment, refer to Figure 2 and Figure 9 As shown, a third locking tooth 132 is provided on the first conical surface of the lower slip 13 near the end of the connector 16. Correspondingly, a fourth locking tooth 83 adapted to the third locking tooth 132 is provided on the outer surface of the second cone 82, so as to limit the lower slip 13 through the cooperation of the third locking tooth 132 and the fourth locking tooth 83.

[0105] Specifically, the third tooth 132 on the first conical surface of the lower slip 13 has a serrated structure, and correspondingly, the fourth tooth 83 on the outer surface of the second cone 82 has a serrated structure that matches the third tooth 132. During setting, the lower slip 13 moves upward along the conical surface of the second cone 82 and gradually expands radially along the second cone 82. The third tooth 132 of the lower slip 13 will mesh with the fourth tooth 83 of the second cone 82 to ensure the positional relationship between the cone and the lower slip 13. This prevents slippage between the lower slip 13 and the second cone 82 after setting, effectively preventing the sealing component from detaching from the lower conical surface of the cone 8 and causing sealing failure, thus ensuring the smooth progress of subsequent operations. The bridge plug provided in this embodiment of the invention, with the special serrated thread in the inner hole at the front end of the cone and the serrated structure at the rear end, achieves self-locking after the bridge plug is set, ensuring that the setting of the bridge plug is more reliable and stable.

[0106] In an optional embodiment, a plurality of first guide protrusions are provided on the end face of the upper collet 3, and correspondingly, a first guide groove 110 adapted to the first guide protrusions is provided on the spindle 1 to circumferentially limit the upper collet 3.

[0107] Multiple second guide protrusions are provided on the end face of the lower slip 13. Correspondingly, the connector 16 is provided with a second guide groove that matches the second guide protrusions to limit the lower slip 13 in the circumferential direction.

[0108] Specifically, the upper slip 3 is located in the middle of the mandrel 1 and the cone 8, and is abutted against the first guide groove of the mandrel 1 and the first cone 81 end of the cone, respectively. The inner side of the large diameter end of the mandrel (i.e. the end with the conical hole) is evenly distributed with first guide grooves 110 at a certain inclination angle. The left end of each upper slip 3 is provided with a first guide boss at the same angle as the first guide groove 110 of the mandrel 1, and during assembly, it is respectively fitted with the first guide groove 110 on the inner side of the mandrel 1 with clearance, thereby realizing the circumferential positioning of the upper slip 31, and can also serve as a guide when the upper slip expands outward.

[0109] Furthermore, the connector 16 in this embodiment of the invention serves to support the lower slip 13 and is equipped with a release force to protect the lower end of the bridge plug and prevent premature setting of the soluble bridge plug. Generally, in the design of the bridge plug, the outer circle of the connector 16 is usually the largest part of the entire bridge plug. Its specific size can be set to be at least 0.5 mm larger than the highest point of the anchor tooth and the outer diameter of other components. The front end of the connector 16 is provided with multiple second guide grooves, which cooperate with the second guide boss 133 on the right end face of the lower slip 13 to fix the circumferential position of each lower slip flap 131 and guide the lower slip flap 131 to expand outwards, allowing the lower slip flap 131 to expand radially in a preset direction. The lower end of the connector 16 is also provided with a large conical surface at a certain angle, which serves to guide the bridge plug.

[0110] The inner hole of the connector 16 is provided with a release thread for connection to the release mandrel via the release thread. The setter sleeve abuts against the left step of the mandrel 1. During the release process, the connector 16 is initially fixedly connected to the release mandrel via the release thread. Under the action of axial force, the setter sleeve pushes the mandrel 1, the upper slip 3, and the cone 8 to move backward. The upper slip 3 expands along the conical surface of the first cone 81, further pushing the sealing assembly and the lower slip 13 to expand outward along the conical surface of the second cone 82. The sealing assembly is compressed, achieving bridge plug sealing. When the release mandrel transmits a certain axial tensile force, the release thread of the connector 16 can be sheared off, thereby achieving bridge plug release and setting. Furthermore, the rear end of the connector 16 is provided with multiple set screw holes for installing set screws to limit the release spindle; this ensures a tight connection between the bridge plug and the release spindle, preventing relative rotation between the release spindle and the bridge plug, and serving to prevent loosening and reverse threading; optionally, the number of set screws can be set to 1 to 4, as per [reference]. Figure 2 As shown, in this embodiment of the invention, the selected quantity is 2.

[0111] In this embodiment of the invention, the dual-slip soluble bridge plug, except for the sealing body 10, anchor teeth, and sealing ring, has all other parts made of soluble metals, typically soluble aluminum alloys, soluble magnesium alloys, soluble magnesium-aluminum alloys, and other soluble materials with a certain strength. The practical application of this invention uses soluble magnesium alloy, which enables rapid dissolution during fracturing operations, achieving a residue-free effect.

[0112] The working process of the bridge plug in this embodiment of the invention for setting, anchoring, and bearing pressure downhole is as follows: After the bridge plug is lowered into the preset position downhole, a certain setting force is first provided by the standard setting tool on the tool string for lowering the bridge plug to release the bridge plug and set it in the designated position inside the casing. Under the action of the axial force provided by the setting tool, the upper slip 3 and lower slip 13 of the bridge plug expand radially and adhere tightly to the inner wall of the casing, while the anchor teeth bite into the inner wall of the casing to form initial anchoring; then, during the fracturing operation, as the pressure inside the wellbore continues to rise, the anchor teeth further bite into the inner wall of the casing, keeping the anchoring state of the bridge plug tending to be stable.

[0113] Specifically, the setting tool mainly includes a setting sleeve and a release mandrel. The release mandrel is threadedly engaged with the connector 16 and positioned by the set screw at the rear end of the connector 16 to fix the position between the mandrel 1 and the connector 16 and to prevent loosening. The end of the setting sleeve abuts against the front step of the mandrel 1. When released, the release mandrel is fixed, and the setting sleeve axially pushes the mandrel 1 forward relative to the release mandrel (i.e., from the first cone 81 to the second cone 82), thereby causing the upper slip 3, the sealing assembly, and the lower slip 13 to expand outward respectively. Finally, the outer circle of the sealing body 10 of the sealing assembly fits with the sleeve to form a seal, and the outer circles of the upper slip 3 and the lower slip 13 are basically fitted with the inner hole of the sleeve. The anchor teeth bite into the sleeve to form a preliminary seal. Then, when the forward movement of the setting sleeve pushes the bridge plug to the preset strength of the release thread, the release thread is sheared, and the release is completed. Then, according to the fracturing construction process requirements, the sealing ball 17 is dropped from the wellhead and continuously pumped to the sealing cone surface at the upper end of the cone body of the bridge plug at the bottom of the well to complete the setting, seal the inner hole of the bridge plug, and achieve the overall sealing of the wellbore inside the casing.

[0114] Reference Figure 10 The diagram shows a schematic of a large-diameter double-slip soluble bridge plug after setting. As can be seen, after setting, the mandrel 1 pushes the upper slip 3 to expand radially. At this time, the anchor teeth of the upper slip 3 anchor into the sleeve wall. Simultaneously, the mandrel 1 moves backward, driving the locking ring 7 to move backward. The locking ring 7 has a C-shaped structure and can radially shrink or expand during movement along the conical surface where the second locking teeth 84 are located, achieving a reverse locking effect. The sealing assembly and the lower slip 13 expand forward and outward relative to the second cone 82 end of the cone. The sealing body 10, supported by the support ring 9, gasket 11, and clamping ring 12, is pressed between the sleeve and the cone, adhering tightly to the sleeve and the conical surface of the second cone 82, forming a preliminary effective seal. The anchor teeth of the lower slip 13 also partially bite into the inner wall of the sleeve to determine the overall position of the bridge plug and ensure that the bridge plug does not slip backward.

[0115] The sealing ball 17 is located at the central conical surface of the front end of the mandrel 1 to achieve overall sealing of the wellbore inside the casing. Furthermore, during the fracturing operation, as the pressure inside the wellbore continues to rise, the anchor teeth further bite into the inner wall of the casing, achieving stable anchoring of the bridge plug; and further compacting the sealing body 10. Under the support and protection of the support ring 9, the gasket ring 11, and the locking ring 7, the sealing body 10 is in a state of increasing pressure, thereby establishing an effective seal inside the wellbore, enabling pressure-bearing and fracturing operations to be completed within a certain period of time.

[0116] The purpose of this invention is to provide a soluble bridge plug with dual slips in the field of key downhole tools for oil and gas drilling and fracturing. Based on existing technology, the overall structure is optimized to eliminate the gaps between the 13 slips after setting, improving the bridge plug's stable setting and pressure bearing under large annular casing and complex operating conditions. This ensures bidirectional locking of the bridge plug, enhances its applicability to setting in large annular casing and withstanding complex well conditions, and increases its dissolution rate. It guarantees stable setting and pressure bearing of the soluble bridge plug, ensuring smooth operation and facilitating rapid well completion and production after fracturing in unconventional oil and gas wells, while reducing construction time and economic costs.

[0117] The large-diameter double-slip soluble bridge plug of this invention combines the advantages of various bridge plug structures, such as the double-slip soluble gel tube bridge plug and the single-slip all-metal soluble bridge plug, and optimizes the design of the mandrel 1, cone 8, lower slip 13, and sealing assembly. The sealing assembly has a support ring 9 at the front end of the sealing body 10 with an internal groove, and a gasket ring 11 and a locking ring 7 at the rear end, which support the sealing body 10 from both ends, ensuring the compaction and reliable support of the seal, thus withstanding greater pressure, ensuring stable setting and pressure bearing of the soluble bridge plug, and ensuring smooth construction. The Z-shaped lower slip 131 structure enables zero gap between the slips after the bridge plug is set, with each slip interlocking and self-locking. During the lowering process, under the action of the clamping ring 12 and clamping ring 15, even in complex situations such as obstruction or jamming, the bridge plug will not prematurely expand or disintegrate under axial force. After setting, there is still an overlap between the slips, preventing the formation of a continuous gap. This allows for support of the sealing assembly throughout the entire circumferential direction during the setting process, achieving a highly efficient sealing effect. It avoids sealing failure due to excessive gaps between the slips or insufficient deformation at the sealing assembly gaps. The mandrel 1 engages with the cone 8 via a special serrated thread through the locking ring 7. The lower slip 13 engages with the second cone end of the cone 8 through a serrated structure. With upper and lower bidirectional slips, the bridge plug achieves bidirectional anchoring and locking after setting, ultimately securing the entire bridge plug as a single unit. The anchoring teeth of the upper slip 3 and lower slip 13 fix the overall position of the bridge plug, significantly improving its anchoring stability and bidirectional pressure-bearing capacity. This prevents slippage, movement, disintegration, or loss of seal during wellbore pressure fluctuations. This effectively improves the pressure-bearing stability and reliability of bridge plugs during fracturing operations, and significantly reduces the volume of soluble rubber seals, increasing the dissolution rate. It not only achieves a large diameter and rapid dissolution of the double-slip soluble bridge plug, but also meets the needs of large annular casing setting and complex well conditions, greatly enhancing the overall performance of the soluble bridge plug. It features double-slip anchoring self-locking, large diameter, short length, rapid dissolution, and high reliability. Its applicable temperature can reach up to 120℃, its maximum pressure resistance reaches 85MPa, and its applicable salinity can reach up to 40000mg / L; effectively ensuring rapid wellbore completion after fracturing operations in unconventional oil and gas wells.

[0118] Furthermore, the soluble bridge plug structure of this invention combines the advantages of various bridge plug structure types, such as the double-slip soluble rubber cylinder bridge plug and the single-slip all-metal soluble bridge plug, and is optimized through design. It adopts slips distributed in opposite directions on both sides of the seal, resulting in strong anchoring and locking capabilities after the bridge plug is set. In contrast, existing single-slip soluble bridge plugs typically only have unidirectional slips, leading to poor anchoring stability and weak reverse pressure bearing capacity after setting. When pressure fluctuations occur at the bottom of the well, the bridge plug is prone to upward slippage, disintegration, or loss of seal. It also reduces the gap between adjacent slips after the bridge plug is set, ensuring bidirectional locking and pressure bearing capacity of the bridge plug, significantly reducing the volume of the soluble rubber seal, and improving the dissolution rate. Moreover, it can meet the needs of small-sized bridge plugs for setting in large annular casings and complex operating conditions.

[0119] Based on the same inventive concept, the present invention also provides the above-mentioned double slip soluble bridge plug system, including: a setting tool and the above-mentioned double slip soluble bridge plug;

[0120] The setting tool includes: a release mandrel and a setting sleeve;

[0121] The release mandrel and the connector are connected by the release thread, and the seat sleeve abuts against the step of the mandrel.

[0122] Regarding the dual-slip soluble bridge plug system in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the dual-slip soluble bridge plug, and will not be elaborated here.

[0123] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0124] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0125] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," just as "comprising" is interpreted as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A double-slip soluble bridge plug, characterized in that, include: Mandrel, upper jaw, cone, sealing assembly, lower jaw and connecting parts; The cone includes a first cone and a second cone connected together. The radial dimension at the connection between the first cone and the second cone is greater than the radial dimension at both ends, and the cone has a hollow structure. The mandrel is connected to the inner wall of the cone, one end of the upper collet is connected to the mandrel, and the other end is provided with a first conical surface that matches the outer surface of the first cone, so as to be fitted onto the first cone; The sealing assembly, lower slip, and connector are connected in sequence. The sealing assembly is used to seal the gap between the second cone and the inner wall of the sleeve, and is provided with a second conical surface that matches the outer surface of the second cone, so as to be fitted onto the second cone; The lower slip is provided with a third conical surface that matches the outer surface of the second cone, so as to be fitted onto the second cone. The lower slip includes multiple lower slip lobes. The lower slip includes a main body, and protrusions and grooves respectively disposed on both sides of the main body, and the protrusions and grooves between adjacent lower slips are adapted to each other; When the groove and the boss of the lower slip are fitted together, the lower slip forms an annular whole; after the bridge plug is set, the adjacent lower slips are staggered from each other, and the staggered distance is less than the length of the contact surface of the adjacent lower slips in the circumferential direction. The lower slip flaps are zig-shaped in the radial direction, and the protrusions and grooves between two adjacent lower slip flaps are staggered in the radial direction, which can achieve zero gap between the lower slip flaps after the bridge plug is set, and support the sealing assembly in the entire circumferential direction.

2. The dual-slip soluble bridge plug as described in claim 1, characterized in that, The thickness of the protrusion of the lower clasp is set to 4~8mm; The length of the protrusion of the lower clasp along the circumferential direction is set to 5~10mm.

3. The dual-slip soluble bridge plug as described in claim 1, characterized in that, The taper of the first cone is greater than the taper of the second cone; The taper of the first cone is 10° to 30°, and the taper of the second cone is 5° to 13°.

4. The dual-slip soluble bridge plug as described in claim 1, characterized in that, One end of the mandrel is provided with a conical hole for cooperating with a sealing ball and a step for cooperating with a seated sleeve, and the other end is provided with an annular groove. A locking ring is provided in the annular groove, and a first locking tooth is provided on the outer surface of the locking ring. Correspondingly, a second locking tooth is provided on the inner wall of the cone to match the first locking tooth, so as to limit the mandrel through the cooperation of the first locking tooth and the second locking tooth; Furthermore, at least one sealing ring is provided between the mandrel and the cone.

5. The dual-slip soluble bridge plug as described in claim 4, characterized in that, The first locking tooth is a sawtooth external thread; correspondingly, the second locking tooth is a sawtooth internal thread adapted to the sawtooth external thread; In the assembled state before the bridge plug is set, the engagement length of the first locking tooth and the second locking tooth is not less than 1 / 5 of the total length of the external thread of the sawtooth.

6. The dual-slip soluble bridge plug as described in claim 1, characterized in that, The sealing assembly includes: at least one support ring, a sealing body, at least one gasket ring, and a clamping ring sequentially sleeved on the second cone; The sealing body is a soluble rubber material or a soluble metal material, used to seal the gap between the second cone and the inner wall of the sleeve; One end of the clamping ring is provided with a stepped hole for engaging with the annular groove of the lower clamping slip to connect the clamping ring with the lower clamping slip.

7. The dual-slip soluble bridge plug as described in claim 6, characterized in that, The support ring, the washer ring, and the clamping ring are provided with grooves along the axial direction, and the grooves of the support ring and the clamping ring are staggered from the grooves of the washer ring.

8. The dual-slip soluble bridge plug as described in claim 6, characterized in that, The inner wall of the sealed body is provided with an extrusion groove.

9. The double-slip soluble bridge plug as described in claim 6, characterized in that, The support ring, sealing body, gasket ring, and clamping ring are ring-shaped structures, and the outer diameter of the sealing body is larger than the outer diameter of the support ring, the gasket ring, and the clamping ring.

10. The dual-slip soluble bridge plug as described in claim 1, characterized in that, The upper slip includes multiple upper slip segments arranged in the circumferential direction. The multiple upper slip segments are clamped together into a ring by a pre-tightening ring and an anti-expansion ring; and the pre-tightening ring and the anti-expansion ring can break under a preset pressure.

11. The dual-slip soluble bridge plug as described in claim 10, characterized in that, The upper slip flap is provided with a plurality of first mounting holes inclined along the direction of the first cone, and the lower slip flap is provided with a plurality of second mounting holes inclined along the direction of the second cone. The first mounting holes and the second mounting holes are used to install anchor teeth.

12. The dual-slip soluble bridge plug as described in claim 1, characterized in that, The number of lower vane segments included in the lower vane is 6 to 12.

13. The dual-slip soluble bridge plug as described in claim 1, characterized in that, A third locking tooth is provided on the first conical surface of the lower slip near the end of the connector. Correspondingly, a fourth locking tooth is provided on the outer surface of the second cone to match the third locking tooth, so as to limit the lower slip through the cooperation of the third locking tooth and the fourth locking tooth.

14. The dual-slip soluble bridge plug as described in claim 1, characterized in that, A first guide protrusion is provided on the end face of the upper collet, and correspondingly, a first guide groove adapted to the first guide protrusion is provided on the spindle to circumferentially limit the upper collet; A second guide protrusion is provided on the end face of the lower slip, and correspondingly, a second guide groove is provided on the connector to fit the second guide protrusion, so as to circumferentially limit the lower slip.

15. The double-slip soluble bridge plug as described in any one of claims 1-14, characterized in that, The inner hole of the connector is provided with a release thread so as to be connected to the release mandrel through the release thread; Furthermore, the connector is provided with multiple set screw holes for installing set screws to limit the release spindle through the set screws.

16. A dual-slip soluble bridge plug system, characterized in that, Includes: a setting tool and a double slip soluble bridge plug as described in any one of claims 1-15; The setting tool includes: a release mandrel and a setting sleeve; The release mandrel and the connector are connected by a release thread, and the seat sleeve abuts against the step of the mandrel.

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