Combined sealing ring type metal soluble bridge plug and its forming assembly method

Abstract

The application discloses a combined sealing ring type metal soluble bridge plug and a forming and assembling method thereof. The bridge plug comprises a cone body, a supporting slip, a combined sealing ring and a guide releasing sub. The supporting slip comprises a plurality of slip units made of soluble metal. The first end of each slip unit is connected to the first end of a limiting hoop ring. The limiting hoop ring and each slip unit are slidably sleeved on the small-diameter end of the first outer conical surface. Each slip unit can climb and expand to abut against the inner wall of a casing or be circumferentially closed. The combined sealing ring can be deformed along with the expansion of the limiting hoop ring. The combined sealing ring comprises a ductile metal inner framework and a soluble rubber sealing ring. The outer wall of the soluble rubber sealing ring is provided with a protrusion. The guide releasing sub can be connected to or separated from the second end of each slip unit. The application improves the sealing and pressure bearing capacity and stability of the metal soluble bridge plug under high temperature and high pressure conditions in a well, and realizes that the soluble bridge plug can be quickly dissolved after completing a fracturing operation at the bottom of the well, reduces the dissolution residues, and reduces the use of high-ductility magnesium alloy metal materials.

Description

Technical Field

[0001] This invention relates to the field of key downhole tools for oil and gas drilling and fracturing, and particularly to a combined sealing ring type soluble metal bridge plug and its molding and assembly method. Background Technology

[0002] As oilfields gradually enter the medium-to-high water-cut stage, the undeveloped formations are increasingly thinner and less efficient. To increase oil recovery and improve oilfield production efficiency, stratified injection and production, and multi-stage fracturing are effective methods for developing special oil layers. Typically, during fracturing, bridge plugs are used to seal the downhole casing and isolate the target formation. Soluble bridge plugs are a new type of stratified fracturing tool for shale gas. After fracturing, the bridge plug body can be completely dissolved by the wellbore temperature and a certain level of salinity in the liquid environment, ensuring full-bore production. This method offers advantages such as low overall cost, short commissioning time, reduced operational risks, and the ability to perform secondary fracturing.

[0003] Most commonly used soluble bridge plugs have a double-slip structure at both ends. They achieve sealing of the downhole casing and interlayer isolation through the elastic deformation of the soluble rubber sleeve under compression. Under certain downhole temperature and salinity conditions, the metal components of soluble bridge plugs can dissolve well, ultimately forming powdery or fine granular residues. In contrast, the soluble rubber sleeve mainly degrades into blocky residues, resulting in slower dissolution and longer cycles. As the number of bridge plugs deployed increases, the accumulation of dissolved residues affects flowback production, often requiring drilling and well cleaning operations, increasing costs. Another type of bridge plug is the all-metal soluble bridge plug. All-metal soluble bridge plugs without rubber can achieve rapid dissolution with less residue. However, due to the high-ductility metal sealing rings used, the pressure drop is significant during the pressure-bearing period, and the cost is higher.

[0004] Therefore, based on years of experience and practice in related industries, the inventor proposes a combined sealing ring type soluble metal bridge plug and its molding and assembly method to overcome the defects of the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a combined sealing ring type soluble metal bridge plug and its molding and assembly method, which overcomes the shortcomings of the prior art, improves the sealing and pressure bearing capacity and stability of the soluble metal bridge plug under high temperature and high pressure conditions downhole, and enables the soluble bridge plug to dissolve quickly after fracturing operations are completed at the bottom of the well, reducing dissolution residues, reducing the use of high ductility magnesium alloy metal materials, shortening the processing cycle, reducing processing risks, ensuring rapid well commissioning and production of unconventional oil and gas wells, and reducing construction cycle and economic costs.

[0006] The object of this invention is achieved as follows: a combined sealing ring type soluble metal bridge plug, comprising,

[0007] A cone, wherein the outer wall of the cone is provided with a first outer conical surface;

[0008] A combined sealing ring is disposed at the second end of the limiting ring and can crawl and expand in diameter along the first outer conical surface as the limiting ring moves along the first outer conical surface. The combined sealing ring includes an extendable metal inner skeleton, and a soluble rubber sealing ring is bonded to the metal inner skeleton. The outer wall of the soluble rubber sealing ring is provided with a protrusion that can seal the inner wall of the sleeve.

[0009] The support slip includes multiple slip units made of soluble metal. The first end of each slip unit is connected to the first end of the limiting ring. The limiting ring and each slip unit can be slidably fitted onto the small-diameter end of the first outer conical surface. The second end of each slip unit can crawl along the first outer conical surface, expand, and abut against the inner wall of the sleeve or close circumferentially.

[0010] The guide release connector can connect to or disconnect from the second end of each of the aforementioned chuck units.

[0011] In a preferred embodiment of the present invention, the metal inner skeleton includes a skeleton body, a skeleton protrusion with a decreasing diameter is provided at the first end of the skeleton body, a side-embedding structure is provided on the side wall of the skeleton protrusion, an end-embedding structure is provided on the end face of the skeleton protrusion and the end face of the first end of the skeleton body, an adhesive layer is coated on the side wall of the skeleton protrusion, the end face of the skeleton protrusion and the end face of the first end of the skeleton body, and the soluble rubber sealing ring is integrally injection bonded to the metal inner skeleton.

[0012] In a preferred embodiment of the present invention, the metal inner frame is provided with a first inner conical hole that mates with the first outer conical surface, and a first groove is provided on the side wall of the first inner conical hole.

[0013] In a preferred embodiment of the present invention, a tapered end bearing surface is provided at the end of the first inner conical hole.

[0014] In a preferred embodiment of the present invention, the bottom angle of the end bearing surface is 5° to 15°.

[0015] In a preferred embodiment of the present invention, the elongation of the metal inner skeleton is ≥12%.

[0016] In a preferred embodiment of the present invention, an inner inclined surface is provided on the inner wall of the slip unit, and the inner inclined surface can fit against the first outer conical surface; a first end inclined surface is provided on the end face of the second end of the slip unit, and a second end inclined surface is provided on the end face of the first end of the guide release connector that can fit against the first end inclined surface; a second groove is provided inward on the second end of the slip unit, and a release key is provided on the first end of the guide release connector that can be inserted into the second groove; a release thread is provided on the inner wall of the first end of the guide release connector.

[0017] In a preferred embodiment of the present invention, a hoop is provided on the outer wall of the second end of each of the slip units, which can close and fix the slip unit and can break during crawling expansion.

[0018] In a preferred embodiment of the present invention, a plurality of slots are provided on the outer wall of the slip unit, and slip teeth that can be embedded in the inner wall of the sleeve are embedded in each slot.

[0019] In a preferred embodiment of the present invention, a first serrated portion is provided on the outer wall of the cone from the small diameter end inward, and a second serrated portion is provided on the inner wall of each of the slip units from the first end inward. The second serrated portion and the first serrated portion are inserted and engaged to fix each of the slip units circumferentially relative to the cone.

[0020] In a preferred embodiment of the present invention, a solution-promoting hole is provided on the cone.

[0021] In a preferred embodiment of the present invention, a central hole is provided axially through the cone body, and a first end of the central hole is provided with a setting cone surface for setting a soluble ball.

[0022] The objective of this invention can also be achieved as follows: a molding and assembly method for the aforementioned combined sealing ring type soluble metal bridge plug includes: using a combined sealing ring molding tool to complete the pressure molding of the combined sealing ring; using a supporting slip tool to process the supporting slip and then connecting the limiting ring to its first end; machining a cone and a guide release joint; inserting the second end of each slip unit of the supporting slip into the guide release joint, and then installing the ring to fix it after closing; and fitting the combined sealing ring, the limiting ring, and the supporting slip onto the small diameter end of the cone to complete the molding and assembly of the combined sealing ring type soluble metal bridge plug.

[0023] In a preferred embodiment of the present invention, the combined sealing ring forming fixture includes a base, a base groove with an inner diameter that is the same as the outer diameter of the metal inner skeleton at the first end of the base, a connecting sleeve on the outer side of the base groove, the inner wall of the connecting sleeve matching the outer circle and protrusion of the soluble rubber sealing ring, an inner bushing coaxially and radially spaced inside the connecting sleeve, the outer wall of the inner bushing matching the inner wall of the soluble rubber sealing ring; and a top cover on the top of the connecting sleeve and the inner bushing.

[0024] In a preferred embodiment of the present invention, when using a combined sealing ring molding fixture to perform combined sealing ring pressure molding, the fixture is preheated to 150°C, a metal inner skeleton is placed in the base, the inner bushing, connecting sleeve and top cover are assembled in sequence, soluble rubber is filled, the pressure head presses down on the top cover, the pressure is maintained at 10-15 MPa, after the rubber overflows smoothly, it is kept at 150°C, and after the heat preservation time is over, the mold is removed, and the combined sealing ring is formed.

[0025] In a preferred embodiment of the present invention, the supporting slip tooling includes a slip mandrel and a pressure cap. The slip mandrel includes a long shaft body. A positioning boss with an increasing diameter is provided at the first end of the long shaft body. A slip rear end fixing groove is provided at the first end of the positioning boss. The pressure cap is sleeved on the second end of the long shaft body. A plurality of slip slit grooves are provided circumferentially at intervals on the positioning boss. The width of the slip slit grooves is greater than the gap between adjacent slip units when the slip unit is supported to the inner wall of the sleeve. A slip front end fixing groove is provided at the end of the pressure cap near the positioning boss. The pressure cap is fixed by a lock nut.

[0026] In a preferred embodiment of the present invention, the undivided support slip body is machined to a set size, placed between the slip mandrel and the pressure cap, locked by a locking nut, and then cut by a cutting tool installed in the reserved slip slit groove to cut the support slip body into a set number of slip units.

[0027] As described above, the combined sealing ring type soluble metal bridge plug and its molding and assembly method of the present invention have the following beneficial effects:

[0028] This invention achieves reliable and stable pressure bearing of the soluble bridge plug through a combination of sealing rings. Unlike double-slip anchoring and rubber sleeve sealing structures, or single-slip anchoring and high-ductility metal sealing structures, this invention achieves reliable sealing using a single-support slip and a combination of sealing rings. It features a simple overall structure, stable pressure bearing, large diameter, and rapid dissolution. It can be quickly dissolved after staged fracturing operations, enabling wellbore completion and production, thus reducing construction time and economic costs.

[0029] This invention improves the sealing and pressure-bearing capacity and stability of soluble metal bridge plugs under high temperature and high pressure conditions downhole, and enables the soluble bridge plugs to dissolve rapidly after fracturing operations are completed at the bottom of the well, reducing dissolution residues, reducing the use of high-ductility magnesium alloy materials, shortening the processing cycle, reducing processing risks, ensuring rapid well commissioning and production of unconventional oil and gas wells, and reducing construction cycle and economic costs. Attached Figure Description

[0030] The accompanying drawings are intended only to illustrate and explain the present invention and do not limit the scope of the invention.

[0031] in:

[0032] Figure 1 : This is a schematic diagram of the combined sealing ring type soluble metal bridge plug of the present invention.

[0033] Figure 2 : This is a schematic diagram of the combined sealing ring of the present invention.

[0034] Figure 3: This is a cross-sectional view of the combined sealing ring of the present invention.

[0035] Figure 4 : This is a schematic diagram of the combined sealing ring forming tooling of the present invention.

[0036] Figure 5 : This is a schematic diagram of the base of the combined sealing ring forming fixture of the present invention.

[0037] Figure 6 : This is a schematic diagram of the support clamping fixture of the present invention.

[0038] Figure 7 : This is a side view of the support clamping fixture of the present invention.

[0039] Figure 8 This is a schematic diagram of the combined sealing ring type soluble metal bridge plug before setting according to the present invention.

[0040] Figure 9 : This is a schematic diagram of the combined sealing ring type soluble metal bridge plug after setting according to the present invention.

[0041] In the picture:

[0042] 1. Cone;

[0043] 2. Combined sealing ring;

[0044] 21. Soluble rubber sealing ring; 211. Upper pressure bearing surface of the rubber ring; 212. Protrusion; 213. Side embedding surface of the rubber ring; 214. Inner conical surface of the rubber ring; 215. Upper embedding surface of the rubber ring;

[0045] 22. Metal inner frame; 221. First inner conical hole; 222. First groove; 223. End embedding structure; 224. Side embedding structure; 225. End bearing surface;

[0046] 23. Top cover; 231. Top cover pressure bearing surface; 232. Stepped top cover pressing surface;

[0047] 24. Inner bushing; 241. Outer conical surface of the inner bushing;

[0048] 25. Connecting sleeve; 251. Inner bushing sealing surface;

[0049] 26. Base; 261. Inner boss of base; 262. Groove of base; 263. Outer boss of base; 264. Vent slot;

[0050] 3. Limiting hoop;

[0051] 4. Support the slip;

[0052] 41. Kawa unit;

[0053] 42. Vault teeth;

[0054] 43. Second groove;

[0055] 45. Pressure cap; 451. Slip mandrel fixing hole; 452. Slip front end fixing groove;

[0056] 46. ​​Slipper mandrel; 461. Slipper inner bore positioning surface; 462. Slipper rear end fixing groove; 463. Slipper slit groove; 464. Mandrel connecting thread;

[0057] 47. Tighten the nut;

[0058] 5. Hoop;

[0059] 6. Guide release connector;

[0060] 700. Inner wall of the sleeve; 701. Adapter push cylinder; 702. Release thread; 703. Sealing ring extrusion surface; 704. Slip tooth embedding surface; 705. Slip cone thread meshing surface; 706. Sealing cone surface. Detailed Implementation

[0061] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0062] The specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, all of which should be considered within the scope of the invention. It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "mounted," "connected," and "linked" should be interpreted broadly; for example, they can refer to mechanical or electrical connections, or internal communication between two elements, and can be direct or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0064] Example 1

[0065] like Figure 1 , Figure 2 , Figure 3 , Figure 8 , Figure 9 As shown, the present invention provides a combined sealing ring type soluble metal bridge plug, comprising,

[0066] Cone 1, the outer wall of cone 1 is provided with a first outer conical surface, the apex angle of the first outer conical surface is between 12° and 24°;

[0067] The combined sealing ring 2 is located at the second end of the limiting ring 3 and can crawl and expand in diameter along the first outer conical surface of the limiting ring 3. The combined sealing ring 2 is a combined structure, including an extendable metal inner skeleton 22, the metal inner skeleton 22 is bonded to a soluble rubber sealing ring 21, and the outer wall of the soluble rubber sealing ring 21 is provided with a protrusion 212 that can seal the inner wall 700 of the sleeve. The soluble rubber sealing ring 21 can be formed into a small rubber tube to achieve the sealing purpose.

[0068] The supporting slip 4 includes multiple slip units 41 made of soluble metal. The first end of each slip unit 41 is connected to the first end of the limiting ring 3. The limiting ring 3 and each slip unit 41 can be slidably fitted onto the small-diameter end of the first outer conical surface. The second end of each slip unit 41 can crawl along the first outer conical surface of the cone to expand its diameter and abut against the inner wall of the sleeve 70° or close circumferentially. The supporting slip 4 is made of high-strength magnesium alloy. Several slip units 41 of the same size form a circumferential shape. The structure of 8 to 12 segments is selected according to the sleeve specifications.

[0069] The guide release connector 6 can connect to or disconnect from the second end of each slip unit 41.

[0070] The combined sealing ring type soluble metal bridge plug of the present invention achieves reliable and stable pressure bearing through the combined sealing ring. The present invention is different from the double slip anchoring and rubber sleeve sealing structure, as well as the single slip anchoring and high ductility metal sealing structure. It can achieve reliable sealing by using a single support slip and combined sealing ring. It has the technical characteristics of simple overall structure, stable pressure bearing, large diameter and fast dissolution. It can be quickly dissolved after staged fracturing operation, realize well opening and production, and reduce construction cycle and economic cost.

[0071] Furthermore, the outer circle of the metal inner skeleton 22 adopts a shoulder design. The metal inner skeleton 22 includes a skeleton body. The first end of the skeleton body is provided with a skeleton protrusion with a decreasing diameter. The side wall of the skeleton protrusion is provided with a side embedding structure 224. The end face of the skeleton protrusion and the end face of the first end of the skeleton body are provided with an end embedding structure 223. The side wall of the skeleton protrusion, the end face of the skeleton protrusion, and the end face of the first end of the skeleton body are coated with an adhesive layer. The soluble rubber sealing ring 21 is integrally injection bonded to the metal inner skeleton 22. The end embedding structure 223 and the side embedding structure 224 can adopt a process groove structure. The cross-section of the process groove structure can be V-shaped, rectangular, toothed, etc., and it is sandblasted and coated with a special high-temperature adhesive for soluble rubber to form an adhesive layer, which facilitates reliable adhesive application to the soluble rubber sealing ring 21.

[0072] Furthermore, the metal inner frame is provided with a first inner conical hole 221 that mates with the first outer conical surface, and a first groove 222 is provided on the side wall of the first inner conical hole 221. The cross-section of the first groove 222 is V-shaped.

[0073] Furthermore, a tapered end bearing surface 225 is provided at the end of the first inner conical hole 221. The end bearing surface 225 constitutes the lower bearing surface of the metal inner frame. In a specific embodiment of the present invention, the bottom angle of the end bearing surface 225 is 5° to 15°, which facilitates concentrated stress deformation under pressure.

[0074] Furthermore, considering the working characteristics, the metal inner skeleton 22 should be made of materials with good ductility, and the elongation of the metal inner skeleton should be ≥12%.

[0075] The soluble rubber sealing ring 21 is made of soluble rubber. The end face of the soluble rubber sealing ring 21 away from the slip unit 41 forms the upper pressure bearing surface 211 of the rubber ring. The upper pressure bearing surface 211 of the rubber ring can be designed as a plane or a small conical surface. The inner hole of the soluble rubber sealing ring 21 is provided with an inner conical surface 214 of the rubber ring that mates with the first outer conical surface of the cone 1. The outer wall of the soluble rubber sealing ring 21 is provided with one or more protrusions 212. The protrusions 212 can be arc-shaped, rectangular, toothed, or other cross-sections to ensure sealing performance. According to the inner skeleton design, the rubber sealing ring is pressed to form a rubber ring side embedding surface 213 and a rubber ring upper embedding surface 215.

[0076] The combined sealing ring 2 can move upward with the support slip 4 under the action of axial force, expand and deform along the first outer conical surface of the cone 1, and finally embed into the annular space between the cone 1 and the inner wall of the sleeve to form a seal. The structure of the combined sealing ring 2 can improve the sealing pressure bearing reliability and stability of the metal soluble bridge plug, and effectively reduce the cost of parts, shorten the processing cycle, and reduce the processing risk of high ductility magnesium alloy metal materials.

[0077] The limiting ring 3 is installed between the combined sealing ring 2 and the supporting slip 4. One side of the limiting ring 3 has a countersunk hole that can wrap the outer circle of the first end of each slip unit 41 into a unified whole. The other side has an inner conical surface that matches the combined sealing ring 2 to facilitate bearing pressure and force.

[0078] Furthermore, an inner inclined surface is provided on the inner wall of the slip unit 41, which can fit against the first outer conical surface. The inner inclined surfaces of each slip unit 41 enclose a conical surface, and the angle of the conical surface is the same as the angle of the first outer conical surface of the cone 1. A first end inclined surface is provided on the end face of the second end of the slip unit, and a second end inclined surface is provided on the end face of the first end (the end near the supporting slip) of the guide release connector 6, which can fit against the first end inclined surface. A second groove 43 is provided inward on the second end of the slip unit, and the second groove forms a slip guide groove. A release key is provided on the first end of the guide release connector 6, which can be inserted into the second groove. A release thread 702 is provided on the inner wall of the first end of the guide release connector. The guide release connector 6 is installed on the second end of the supporting slip 4. The release thread 702 is designed according to the setting release force and is used to connect with the adapter (existing technology). The first end bevel and the second end bevel cooperate, and the release key cooperates with the second groove 43 to guide the expansion of the support slip 4, ensuring that the slip unit 41 is evenly distributed along the circumferential direction when crawling and expanding.

[0079] Furthermore, each slip unit 41 has a clamping ring 5 on its second end outer wall that can close and fix the slip unit and break during crawling expansion. Specifically, a circumferential groove is provided on the second end outer wall of each slip unit 41. During initial operation, the clamping ring 5 is installed in the circumferential groove, clamping the segmented slip units 41 into a whole. When the release force reaches a certain level, the clamping ring 5 breaks, thus supporting the free expansion of the slip 4.

[0080] Furthermore, the outer wall of the slip unit 41 is provided with multiple slots, each slot containing slip teeth 42 that can embed into the inner wall of the sleeve. The slots are evenly distributed circular holes with a certain angle on the outer circumference of the supporting slip, and the slip teeth 42 have high hardness to ensure reliable anchoring. During operation, the supporting slip 4 moves forward along the cone under the action of axial force and simultaneously expands radially, so that the slip teeth 42 embed into the inner wall of the sleeve by 70°, achieving setting and sealing.

[0081] Furthermore, a first serrated portion is provided on the outer wall of the cone 1 from the small diameter end inward, and a second serrated portion is provided on the inner wall of each slip unit from the first end inward. The second serrated portion and the first serrated portion are inserted and matched to fix each slip unit relative to the cone circumferentially, ensuring that each slip unit 41 firmly grips the cone 1 during the setting process, and preventing the soluble bridge plug from rebounding and failing during the setting process.

[0082] Furthermore, a dissolution-promoting hole is provided on the cone 1 to meet the need for rapid dissolution.

[0083] Furthermore, a central hole is provided axially through the cone 1, and a setting cone surface 706 for setting the soluble ball is provided at the first end of the central hole. During downhole operation, when the soluble ball is pressed against the bridge plug, it seals the central hole of the bridge plug, establishing a seal at the setting cone surface 706 (the sealing surface of the soluble ball in the cone).

[0084] The working principle of the combined sealing ring type soluble metal bridge plug is as follows: After installing the combined sealing ring type soluble metal bridge plug as described above, install the adapter (existing technology). Place the combined sealing ring type soluble metal bridge plug inside the setting sleeve. Apply the adapter pusher 701 to the cone 1. Install the adapter mandrel at the release thread 702 of the guide release connector 6. Under the action of axial force, the support slip 4 moves forward along the cone 1 and simultaneously expands radially. When it expands to a certain extent, the clamping ring 5 shears off. The slip unit 41 continues to expand, causing the slip teeth 42 to embed into the inner wall 700 of the sleeve, forming the slip tooth embedding surface 704 to achieve setting. The first serrated part of the cone 1 and the second serrated part of each slip unit form the slip cone thread meshing surface 705. Under the action of axial force, the limiting ring 3 and the combined sealing ring 2 simultaneously achieve radial expansion, and finally embed into the annular space between the cone 1 and the inner wall 700 of the sleeve, forming the sealing ring extrusion surface 703. After reaching the release force, the guide release joint 6 is disengaged due to thread cutting, and the soluble ball is inserted. The soluble ball and the cone 1 form the cone soluble ball sealing surface, and the soluble bridge plug completes the setting and forms a seal.

[0085] This invention provides a molding and assembly method for a combined sealing ring type soluble metal bridge plug, comprising: using a combined sealing ring molding tool to complete the pressure molding of the combined sealing ring 2; using a supporting slip tool to process the supporting slip 4 and then connecting the limiting ring 5 to its first end; machining the cone 1 and the guide release joint 6; inserting the second end of each slip unit of the supporting slip 4 into the guide release joint 6, and fixing it with the ring 5 after closing; and fitting the combined sealing ring 2, the limiting ring 3, and the supporting slip 4 onto the small diameter end of the cone 1 to complete the molding and assembly of the combined sealing ring type soluble metal bridge plug.

[0086] Example 2

[0087] like Figure 4 , Figure 5 As shown, the combined sealing ring forming fixture includes a base 26. The first end of the base 26 is provided with a base groove 262, the inner diameter of which is the same as the outer diameter of the metal inner skeleton 22. A connecting sleeve 25 is provided on the outer side of the base groove 262. The inner wall of the connecting sleeve 25 matches the outer circle and protrusion of the soluble rubber sealing ring 21. An inner bushing 24 is provided coaxially and radially spaced inside the connecting sleeve 25. The outer wall of the inner bushing 24 matches the inner wall of the soluble rubber sealing ring 21. A top cover 23 is provided on the top of the connecting sleeve 25 and the inner bushing 24.

[0088] The base 26 is placed at the bottom of the entire tooling. The first end (top end) is provided with a base groove 262 that is the same size as the bottom of the metal inner skeleton 22. Before pressing, the metal inner skeleton is placed in the base groove 262. At the same time, there are base inner bosses 261 that cooperate with the inner bushing 24 and base outer bosses 263 that cooperate with the connecting sleeve 25. There is an exhaust groove 264 on the end face that cooperates with the connecting sleeve 25. In order to facilitate the disassembly of the tooling, a mold release groove is also provided on the base.

[0089] The connecting sleeve 25 is placed between the top cover 23 and the base 26. The upper end of the inner hole of the connecting sleeve 25 is provided with an inner conical hole that fits with the top cover 23. During the pressing process, it can achieve axial introduction and facilitate demolding and separation. The inner wall of the connecting sleeve 25 matches the outer circle and protrusion of the soluble rubber sealing ring to form the inner bushing sealing surface 251. The lower end of the connecting sleeve 25 is provided with an exhaust hole or groove for exhaust. The exhaust hole is located in the area where the upper end of the outer circle of the metal inner skeleton 22 meets the soluble rubber sealing ring 21 to ensure the smoothness and flatness of the outer surface of the soluble rubber sealing ring 21.

[0090] The inner sleeve 24 is placed between the base 26 and the top cover 23, connecting the inside of the sleeve 25. The outer wall of the inner sleeve 24 matches the inner wall of the soluble rubber sealing ring 21 to form the outer conical surface 241 of the inner sleeve. The upper end has a positioning outer circle that matches the top cover 23, and the lower end has a positioning inner hole that matches the base 26, ensuring that the metal inner skeleton 22 and the soluble rubber sealing ring 21 are coaxial.

[0091] The top cover 23 adopts a blind hole structure. Its upper surface has a top cover pressure bearing surface 231, serving as the contact plane for the pressure head. The lower end has a protruding stepped top cover pressing surface 232. The inner surface has a cylindrical inner hole that mates with the inner bushing 24, and the outer surface has an outer conical surface that mates with the connecting sleeve 25. The injection pressure is transmitted through the lower surface of the boss. A mold release groove can be pre-reserved at the contact end between the outer circle of the top cover 23 and the connecting sleeve 25 for easy mold release. Additionally, the upper end of the top cover 23 has a threaded process hole for convenient mold release.

[0092] When using a combined sealing ring molding fixture for pressure molding of combined sealing rings, first prepare all parts, preheat the fixture to 150℃, place the metal inner skeleton 22 inside the base 26, assemble the inner bushing 24, connecting sleeve 25 and top cover 23 in sequence, fill with enough soluble rubber, press down the top cover 23 with the pressure head, maintain the pressure at 10-15MPa, after the rubber overflows smoothly, keep it at 150℃, after the heat preservation time is over, remove the mold, and the combined sealing ring is formed.

[0093] The combined sealing ring molding fixture can smoothly realize the molding of combined sealing rings, and has the characteristics of quick glue pressing, convenient demolding, and simple maintenance.

[0094] Example 3

[0095] like Figure 6 , Figure 7As shown, the supporting slip fixture includes a slip mandrel 46 and a pressure cap 45. The slip mandrel 46 includes a long shaft body, which is used to pass through and fix the body of the supporting slip 4 (a sleeve-like body when the slip unit is not divided and can be expanded in diameter). The outer wall of the long shaft body forms the slip inner hole positioning surface 461. The first end of the long shaft body is provided with a positioning boss with an increasing diameter. The first end of the positioning boss is provided with a slip rear end fixing groove 462, which is used to fix the first end of the supporting slip 4 body. A pressure cap 45 is fitted onto the second end of the shaft body; multiple slip grooves 463 are spaced circumferentially along the positioning boss, the width of which is greater than the gap between adjacent slip units 41 when the slip unit 41 is supported to the inner wall of the sleeve by 700, to ensure that the supporting slip 4 can be machined in place; a slip front fixing groove 452 is provided at the end of the pressure cap 45 near the positioning boss, which is used to fix the second end of the supporting slip 4, and the pressure cap 45 is fixed to the slip mandrel 46 by a locking nut 47. A mandrel connecting thread 464 is provided at the second end of the long shaft body, and a slip mandrel fixing hole 451 is provided axially through the pressure cap 45. After the second end of the long shaft body passes through the slip mandrel fixing hole 451, the locking nut 47 is threadedly connected to the mandrel connecting thread 464 to tighten and fix the pressure cap 45.

[0096] The shape of the support slip 4 is directly related to the stress state when the support slip opens. In order to ensure the stability and reliability of the operation, the size and angle of each slip unit 41 should be uniform and consistent. Support slip processing fixtures are used for processing.

[0097] When manufacturing the support slip 4, the body of the support slip 4 without segmentation of slip units is machined to a set size, placed between the slip mandrel 46 and the pressure cap 45, locked by the locking nut 47, and cut by installing the cutting tool through the reserved slip slit groove 463 to cut the body of the support slip 4 into a set number of slip units.

[0098] As described above, the combined sealing ring type soluble metal bridge plug and its molding and assembly method of the present invention have the following beneficial effects:

[0099] This invention achieves reliable and stable pressure bearing of the soluble bridge plug through a combination of sealing rings. Unlike double-slip anchoring and rubber sleeve sealing structures, or single-slip anchoring and high-ductility metal sealing structures, this invention achieves reliable sealing using a single-support slip and a combination of sealing rings. It features a simple overall structure, stable pressure bearing, large diameter, and rapid dissolution. It can be quickly dissolved after staged fracturing operations, enabling wellbore completion and production, thus reducing construction time and economic costs.

[0100] This invention improves the sealing and pressure-bearing capacity and stability of soluble metal bridge plugs under high temperature and high pressure conditions downhole, and enables the soluble bridge plugs to dissolve rapidly after fracturing operations are completed at the bottom of the well, reducing dissolution residues, reducing the use of high-ductility magnesium alloy materials, shortening the processing cycle, reducing processing risks, ensuring rapid well commissioning and production of unconventional oil and gas wells, and reducing construction cycle and economic costs.

[0101] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A combined sealing ring type soluble metal bridge plug, characterized in that, include, A cone, wherein the outer wall of the cone is provided with a first outer conical surface; A combined sealing ring is disposed at the second end of the limiting ring and can crawl and expand in diameter along the first outer conical surface as the limiting ring moves along the first outer conical surface. The combined sealing ring includes an extendable metal inner skeleton, and a soluble rubber sealing ring is bonded to the metal inner skeleton. The outer wall of the soluble rubber sealing ring is provided with a protrusion that can seal the inner wall of the sleeve. The support slip includes multiple slip units made of soluble metal. The first end of each slip unit is connected to the first end of the limiting ring. The limiting ring and each slip unit can be slidably fitted onto the small-diameter end of the first outer conical surface. The second end of each slip unit can crawl along the first outer conical surface, expand, and abut against the inner wall of the sleeve or close circumferentially. A guide release connector, capable of connecting to or disconnecting from the second end of each of the aforementioned slip units; The metal inner skeleton includes a skeleton body, a skeleton protrusion with a decreasing diameter is provided at the first end of the skeleton body, a side-embedding structure is provided on the side wall of the skeleton protrusion, and an end-embedding structure is provided on the end face of the skeleton protrusion and the end face of the first end of the skeleton body. An adhesive layer is coated on the side wall of the skeleton protrusion, the end face of the skeleton protrusion and the end face of the first end of the skeleton body. The soluble rubber sealing ring is integrally injection bonded to the metal inner skeleton. The inner wall of the slip unit is provided with an inner inclined surface, which can fit against the first outer conical surface; the end face of the second end of the slip unit is provided with a first end inclined surface, and the end face of the first end of the guide release connector is provided with a second end inclined surface that can fit against the first end inclined surface; the second end of the slip unit is provided with a second groove inward, and the first end of the guide release connector is provided with a release key that can be inserted into the second groove; the inner wall of the first end of the guide release connector is provided with a release thread. Each of the aforementioned slip units has a hoop on the outer wall of its second end that can close and fix the slip unit and break during crawling expansion.

2. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The metal inner frame is provided with a first inner conical hole that mates with the first outer conical surface, and a first groove is provided on the side wall of the first inner conical hole.

3. The combined sealing ring type soluble metal bridge plug as described in claim 2, characterized in that, The end of the first inner conical hole is provided with a conical end bearing surface.

4. The combined sealing ring type soluble metal bridge plug as described in claim 3, characterized in that, The bottom angle of the end bearing surface is 5° to 15°.

5. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The elongation of the metal inner skeleton is ≥12%.

6. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The outer wall of the slip unit is provided with multiple slots, and each slot is inlaid with slip teeth that can be embedded in the inner wall of the sleeve.

7. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The outer wall of the cone is provided with a first serrated portion from the small diameter end inward, and the inner wall of each slip unit is provided with a second serrated portion from the first end inward. The second serrated portion and the first serrated portion are inserted and engaged to fix each slip unit circumferentially relative to the cone.

8. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The cone is provided with a solution-promoting hole.

9. The combined sealing ring type soluble metal bridge plug as described in claim 1, characterized in that, The cone body has a central hole that extends axially through it, and the first end of the central hole is provided with a setting cone surface for setting the soluble ball.

10. A method for molding and assembling a combined sealing ring type soluble metal bridge plug as described in any one of claims 1 to 9, characterized in that, include: The combined sealing ring is formed by pressure molding using a combined sealing ring forming tool. After the supporting slip is processed using a supporting slip tool, the limiting ring is connected to its first end. The cone and guide release joint are machined and formed; the second end of each slip unit of the supporting slip is inserted into the guide release joint and then the clamping ring is installed to fix it after closing; the combined sealing ring, the limiting clamping ring and the supporting slip are sleeved on the small diameter end of the cone to complete the forming and assembly of the combined sealing ring type metal soluble bridge plug.

11. The molding and assembly method of the combined sealing ring type soluble metal bridge plug as described in claim 10, characterized in that, The combined sealing ring forming fixture includes a base, a base groove with an inner diameter that is the same as the outer diameter of the metal inner skeleton at the first end of the base, a connecting sleeve on the outer side of the base groove, the inner wall of the connecting sleeve matching the outer circle and protrusion of the soluble rubber sealing ring, an inner bushing coaxially and radially spaced inside the connecting sleeve, the outer wall of the inner bushing matching the inner wall of the soluble rubber sealing ring; and a top cover on the top of the connecting sleeve and the inner bushing.

12. The molding and assembly method of the combined sealing ring type soluble metal bridge plug as described in claim 11, characterized in that, When using a combined sealing ring molding fixture for pressure molding of combined sealing rings, the fixture is preheated to 150℃. A metal inner skeleton is placed inside the base, and the inner bushing, connecting sleeve and top cover are assembled in sequence. Soluble rubber is filled in, and the pressure head is pressed down on the top cover. The pressure is maintained at 10-15MPa. After the rubber overflows and becomes smooth, it is kept at 150℃. After the heat preservation time is over, the mold is removed, and the combined sealing ring is formed.

13. The molding and assembly method of the combined sealing ring type soluble metal bridge plug as described in claim 10, characterized in that, The supporting slip tooling includes a slip mandrel and a pressure cap. The slip mandrel includes a long shaft body. The first end of the long shaft body is provided with a positioning boss with an increasing diameter. The first end of the positioning boss is provided with a slip rear end fixing groove. The pressure cap is sleeved on the second end of the long shaft body. The positioning boss is provided with multiple slip slit grooves spaced circumferentially. The width of the slip slit grooves is greater than the gap between adjacent slip units when the slip unit is supported to the inner wall of the sleeve. The pressure cap is provided with a slip front end fixing groove at the end near the positioning boss. The pressure cap is fixed by a lock nut.

14. The molding and assembly method of the combined sealing ring type soluble metal bridge plug as described in claim 13, characterized in that, The undivided support slip body is machined to the set size, placed between the slip mandrel and the pressure cap, and locked with a lock nut. The support slip body is then cut into a set number of slip units by installing a cutting tool through the reserved slip slit groove.

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