Controllable fully-dissolvable bridge plug and use method therefor

Abstract

A controllable fully-dissolvable bridge plug and a use method therefor. The bridge plug comprises a central tube (2), a setting assembly sealingly engaged with the outer peripheral surface of the central tube, and a sealing rod (5) sealingly engaged with the inner peripheral surface of the central tube; the setting assembly comprises a rubber sleeve (12), a slip (10), and a push sleeve (9); the central tube and the setting assembly are made of a dissolvable material; the central tube is provided with a dissolution-resistant layer only on the outer surface area other than the inner peripheral surface engaged with the sealing rod; the slip and the push sleeve are provided with a dissolution-resistant layer only on the outer surface area other than the inner peripheral surface engaged with the central tube; and the sealing rod can be detached from the central tube to allow the central tube and the setting assembly to be directionally dissolved from inside to outside. By performing dissolution resistance treatment on each component, accidental dissolution of the bridge plug can be avoided, and the bridge plug can be controlled to start to dissolve as needed, thereby improving the controllability of dissolution of the bridge plug; moreover, the bridge plug can be completely dissolved, thereby avoiding or reducing the impact on subsequent oil and gas exploitation.

Description

Controlled total dissolution bridge plugs and their usage methods

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411574654.5, filed on November 6, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the technical field of oil and gas well tools, and more particularly to a controllable total dissolution bridge plug, and a method of using a controllable total dissolution bridge plug. Background Technology

[0004] Currently, the known methods for quickly running production tubing after oil and gas well fracturing are either running the drill string under pressure using a live drilling rig or running the production tubing under pressure using coiled tubing. However, live drilling is time-consuming and costly, and the limited availability of live drilling rigs in the market leads to a significant shortage of production tubing. Furthermore, using live drilling rigs in conjunction with production tubing often results in other high-risk wells being shut down, affecting the progress of fluid drainage and production, and hindering the efficient development of oil and gas resources.

[0005] To improve drilling efficiency, control operating costs, and ensure effective well completion and production, pump-opening temporary plugs are used to seal high-pressure areas in directional oil and gas wells with low well pressure after fracturing. This allows for the installation of production tubing at atmospheric pressure at the wellhead, thereby accelerating well completion and production. However, currently used pump-opening temporary plugs lack the ability to completely dissolve and eliminate their own pressure, easily causing wellbore blockage and production stoppages during subsequent well workover. Furthermore, temporary plugs made of soluble materials are limited by the properties of these materials, resulting in limited pressure resistance, poor controllability of component dissolution, and significant susceptibility to interference from various operating conditions, impacting construction safety. Especially after sealing the wellbore, the tool's condition is uncontrollable and unreliable, posing well control risks for safe atmospheric pressure drilling at the wellhead. Summary of the Invention

[0006] One of the technical problems this disclosure aims to solve is that the dissolution after the bridge plug seals the wellbore is difficult to control.

[0007] To address the aforementioned technical problems, this disclosure provides a controllable total dissolution bridge plug, comprising a central tube, a sealing assembly sealingly joined to the outer circumferential surface of the central tube, and a sealing rod sealingly joined to the inner circumferential surface of the central tube. The sealing assembly includes a rubber sleeve, a slip, and a push sleeve located at the upper part of the central tube. The central tube and the sealing assembly are made of a soluble material. The central tube has a solvent-resistant layer only on its outer surface areas other than the inner circumferential surface that engages with the sealing rod. The slip and the push sleeve also have solvent-resistant layers only on their outer surface areas other than the inner circumferential surface that engages with the central tube. The sealing rod can disengage from the central tube when its upper end face is subjected to a predetermined pressure, thereby allowing the central tube and the sealing assembly to dissolve directionally from the inside out.

[0008] In some embodiments, a release lever is further included, which is partially inserted into the upper end of the central tube, and the release lever and the central tube are connected by a first shear pin.

[0009] In some embodiments, the release lever is provided with a pressure transmission channel extending from the outer peripheral surface of the portion of the release lever located outside the central tube to the lower end surface.

[0010] In some embodiments, a first sealing ring is provided on the upper outer periphery of the sealing rod, a second sealing ring is provided on the lower outer periphery of the sealing rod, an annular recess is provided on the outer periphery of the sealing rod between the first sealing ring and the second sealing ring, and an internal flow channel is provided inside the sealing rod to communicate with the annular recess and the upper space of the sealing rod.

[0011] In some embodiments, the upper end face of the sealing rod is provided with a blind hole communicating with the internal flow channel, and the blind hole is provided with sealing grease and a slidable balance plug that seals the outlet of the blind hole.

[0012] In some embodiments, a third shear pin is provided between the push sleeve and the central tube.

[0013] In some embodiments, a support base is provided at the lower end of the central tube, the upper part of the support base is engaged with the outer peripheral surface of the lower end of the central tube, the lower end of the sealing rod is engaged with the inner peripheral surface of the lower part of the support base, a second shear pin is provided between the sealing rod and the support base, and the support base is provided with a solvent-resistant layer only in the outer surface area other than the inner peripheral surface engaged with the central tube and the sealing rod.

[0014] In some embodiments, the sealing assembly includes two slips located at both axial ends of the rubber sleeve.

[0015] In some embodiments, the sealing assembly further includes a cone located between the slip and the cartridge, the cone having a tapered portion that partially inserts into the slip, and the cone having a solvent-resistant layer on its outer surface only in areas other than the inner circumferential surface that engages with the center tube.

[0016] In some embodiments, the cone has an umbrella-shaped portion connected to the conical portion, the umbrella-shaped portion forming a conical space for accommodating the insertion of the rubber sleeve portion.

[0017] In some embodiments, the umbrella-shaped portion is provided with a plurality of circumferentially spaced slits to divide the umbrella-shaped portion into a plurality of umbrella petals that can be bent and deformed outwards.

[0018] In some embodiments, an annular groove is provided on the outer periphery of the cone between the conical portion and the umbrella-shaped portion to allow each of the umbrella petals to bend outward along the annular groove.

[0019] In some embodiments, a fourth shear pin is provided between the cone and the central tube.

[0020] In some embodiments, the rubber sleeve is made of soluble rubber.

[0021] In some embodiments, the central tube and the other components of the sealing assembly, excluding the rubber sleeve, are made of magnesium-aluminum alloy, and the solvent-resistant layer comprises a ceramic film and an organic coating made by micro-arc oxidation.

[0022] In some embodiments, the organic coating is a polytetrafluoroethylene coating.

[0023] On the other hand, embodiments of this disclosure provide a method for using the controllable total dissolution bridge plug described above, including:

[0024] Drilling begins, and the bridge plug is lowered into the oil and gas well.

[0025] A seat, which is seated in the sleeve by the seat assembly;

[0026] The pump is turned on, and the preset pressure is injected to cause the sealing rod to disengage from the central tube;

[0027] Dissolution occurs as follows: the central tube dissolves from the inside out, the seat assembly dissolves from the inside out, and the bridge plug gradually dissolves completely.

[0028] By implementing the above technical solution and performing anti-dissolution treatment on each component, the accidental dissolution of the bridge plug can be avoided. Furthermore, the dissolution of the bridge plug can be controlled as needed, improving the controllability of the bridge plug dissolution. Moreover, the entire bridge plug can be dissolved, thus avoiding or reducing the impact on subsequent oil and gas extraction. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is a schematic diagram of the initial state of the controllable total dissolution bridge plug disclosed in an embodiment of this disclosure;

[0031] Figure 2 is a structural schematic diagram of the seated state of the controllable total dissolution bridge plug disclosed in an embodiment of this disclosure;

[0032] Figure 3 is a structural schematic diagram of the open and dissolved state of the controllable total dissolution bridge plug disclosed in an embodiment of this disclosure;

[0033] Figure 4 is a schematic diagram of the structure of the release lever disclosed in the embodiment of this disclosure;

[0034] Figure 5 is a schematic diagram of the structure of the cone disclosed in an embodiment of this disclosure.

[0035] Explanation of reference numerals in the attached drawings: 1-Release lever; 2-Central tube; 3-First shear pin; 4-Sealing ring; 5-Sealing rod; 6-First sealing ring; 7-Balance plug; 8-Third shear pin; 9-Push sleeve; 10-Slipper; 11-Cone; 12-Rubber sleeve; 13-Support seat; 14-Anti-reverse pin; 15-Second sealing ring; 16-Second shear pin; 17-Sealing grease; 18-Fourth shear pin; 19-Pressure transmission channel; 20-Conical part; 21-Umbrella-shaped part; 22-Annular groove; 23-Annular recess; 24-Internal flow channel. Detailed Implementation

[0036] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0037] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0038] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and 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, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0040] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0041] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0042] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0043] Referring to Figures 1-5, this solution provides a controllable total dissolution bridge plug, which includes a central tube 2, a sealing assembly sealed to the outer circumferential surface of the central tube 2, and a sealing rod 5 sealed to the inner circumferential surface of the central tube 2. The sealing assembly includes a rubber sleeve 12, a slip 10, and a push sleeve 9 located at the upper part of the central tube 2. The central tube 2 and the sealing assembly are made of a soluble material. The central tube 2 has a solvent-resistant layer only on the outer surface area other than the inner circumferential surface that engages with the sealing rod 5. The slip 10 and the push sleeve 9 also have solvent-resistant layers only on the outer surface areas other than the inner circumferential surface that engages with the central tube 2. The sealing rod 5 can disengage from the central tube 2 when its upper end face is subjected to a predetermined pressure, so as to allow the central tube 2 and the sealing assembly to dissolve directionally from the inside out.

[0044] The central tube 2 is the main supporting structure, which can support the seat assembly and can be connected to other structures.

[0045] The sealing assembly includes a rubber sleeve 12, a slip 10, and a push sleeve 9, which are fitted onto the central tube 2. The inner circumferential surface of each component is sealed to the outer circumferential surface of the central tube 2 to prevent other fluids from entering between the central tube 2 and these components, and to prevent the components from dissolving under the action of fluids.

[0046] Among them, the rubber sleeve 12 is the core sealing structure of the sealing assembly. It can expand radially outward to seal on the inner circumferential surface of the casing, thereby achieving sealing, which means stratifying the oil and gas well.

[0047] The 10 can also expand and deform radially outward, thereby locking the tool on the inner circumferential surface of the sleeve and preventing the tool from moving along the length of the sleeve, thus keeping it in a specific target position.

[0048] The push sleeve 9 is an annular structure fitted onto the central tube 2. It is located at the upper part of the central tube 2. When a setting is required, the push sleeve 9 can be pushed downward relative to the central tube 2 by a setting tool. This causes the pressure of the push sleeve 9 to act on the slip 10 and the rubber sleeve 12, so that the slip 10 can be locked onto the sleeve and the rubber sleeve 12 expands and sets onto the sleeve.

[0049] In addition, a sealing rod 5 is installed inside the central tube 2 to seal the inner circumferential surface of the central tube 2, preventing it from contacting the fluid in the oil and gas well, thus protecting the central tube 2.

[0050] Specifically, the central tube 2 is made of a soluble material, and the inner circumferential surface of the part that seals with the sealing rod 5 is not specially treated, while other parts are provided with a solvent-resistant layer, which can prevent the fluid in contact from dissolving the central tube 2.

[0051] In addition, the slip 10 and the push sleeve 9 are also made of soluble materials, and their inner circumferential surfaces that are sealed to the central tube 2 are not specially treated, while the outer surfaces of other parts are provided with a solvent-resistant layer to prevent the fluid slip 10 and the push sleeve 9 from contacting each other.

[0052] In its initial state, the exposed surfaces of the bridge plug, including the central tube 2, slips 10, and push sleeve 9, are protected from dissolution by the fluid due to the presence of an anti-dissolution layer. After setting, when dissolution of the bridge plug is required, pressure is applied to the upper end of the sealing rod 5, causing it to detach from the central tube 2 and expose its inner circumferential surface (the surface without the anti-dissolution layer). This allows the central tube 2 to begin dissolving. After the central tube 2 dissolves, the inner circumferential surfaces of the slips 10 and push sleeve 9 are exposed, and they also begin to dissolve. It can be seen that by applying anti-dissolution treatment to specific locations of each component, the bridge plug can dissolve almost unaffected by external factors in its initial state, and dissolution can begin from the inside out as needed.

[0053] In addition, the glue cartridge 12 is also made of a soluble material. Because it is elastic, its material is different from that of other parts, and its dissolution rate is different from that of other parts, that is, it is significantly slower than other parts. It can meet the usage requirements within the service life (it will not dissolve prematurely when it is not needed to dissolve), so it does not need to be treated with solvent inhibition.

[0054] In this solution, by performing anti-dissolution treatment on each component, the accidental dissolution of the bridge plug can be avoided, and the dissolution of the bridge plug can be controlled as needed, which improves the controllability of the bridge plug dissolution. Furthermore, the entire bridge plug can be dissolved, thus avoiding or reducing the impact on subsequent oil and gas extraction.

[0055] In some embodiments, the controllable total dissolution bridge plug also includes a release rod 1 partially inserted into the upper end of the central tube 2. The release rod 1 and the central tube 2 are connected by a first shear pin 3. The upper end of the release rod 1 is provided with threads for connection with the sealing tool. The first shear pin 3 is provided between the release rod 1 and the central tube 2, passing through the central tube 2 and partially inserted into the release rod 1, thereby achieving a fixed connection between the release rod 1 and the central tube 2. Multiple first shear pins 3 can be spaced apart circumferentially to make the force between the release rod 1 and the central tube 2 more uniform in the circumferential direction. After the sealing is completed, the rubber sleeve 12 and slips 10 are engaged with the casing. When a release operation is required, an upward pulling force is applied to the release rod 1 to shear the first shear pin 3, thereby disconnecting the connection between the release rod 1 and the central tube 2, allowing the tubing and other equipment to be extracted from the oil and gas well.

[0056] In some embodiments, the release lever 1 is provided with a pressure transmission channel 19 extending from the outer peripheral surface of the portion of the release lever 1 located outside the central tube 2 to its lower end surface. Referring to Figure 4, the pressure transmission channel 19 includes a radial portion and an axial portion. The radial portion is located in the middle of the release lever 1, and the axial portion extends downward from the radial portion, i.e., towards the sealing rod 5. The radial portion is located outside the central tube 2 and is not threaded, i.e., outside the sealing tool, to allow fluid in the casing to enter the portion of the release lever 1 from the radial portion and reach the sealing rod 5. Conventional bridge plug sealing operations have a certain risk of jamming. When the bridge plug cannot be released after setting, hydraulic force can be transmitted to the upper end of the sealing rod 5 through the pressure transmission channel 19, so that the sealing rod 5 is pushed downward and disengaged from the central tube 2, and the central tube 2 and the setting assembly are gradually dissolved, i.e., the bridge plug dissolution operation is initiated in advance to ensure smooth unblocking on site.

[0057] In some embodiments, a first sealing ring 4 is provided on the upper outer periphery of the sealing rod 5, and a second sealing ring 15 is provided on the lower outer periphery of the sealing rod 5. An annular recess 24 is provided on the outer periphery of the sealing rod 5 between the first sealing ring 4 and the second sealing ring 15. An internal flow channel 23 is provided inside the sealing rod 5, connecting the annular recess 24 and the upper space of the sealing rod 5. The upper and lower parts of the outer periphery of the sealing rod 5 may be provided with annular grooves to accommodate the first sealing ring 4 and the second sealing ring 15. The first sealing ring 4 and the second sealing ring 15 can be pressed against the inner circumferential surface of the central tube 2 to improve the sealing effect between the sealing rod 5 and the central tube 2, and to prevent or reduce fluid from entering between the central tube 2 and the sealing rod 5. In addition, an annular recess 24 is provided on the outer periphery of the seal 5, located between the first sealing ring 4 and the second sealing ring 15. The annular recess 24 is connected to the space above the sealing rod 5 through the internal flow channel 23 inside the sealing rod 5. This allows the fluid reaching the upper part of the sealing rod 5 to transmit pressure to the annular recess 24. On the one hand, this balances the internal and external pressures of the central tube 2, improving the pressure-bearing safety of the parts. On the other hand, it reduces the pressure difference on both sides of the first sealing ring 4 axially, keeping the pressure on both sides of the first sealing ring 4 as balanced as possible, thus improving the sealing reliability of the first sealing ring 4. In some embodiments, the internal flow channel 23 can extend from the annular recess 24 to the upper end face of the sealing rod 5.

[0058] In some embodiments, the upper end face of the sealing rod 5 is provided with a blind hole communicating with the internal flow channel 23. A sealing grease 17 and a slidable balance plug 7 sealing the outlet of the blind hole are disposed in the blind hole. The upper end of the sealing rod 5 has a blind hole communicating with the internal flow channel 23. The blind hole contains the slidable balance plug 7 and the sealing grease 17. The fluid in the upper part of the sealing rod 5 can exert pressure on the balance plug 7, and the pressure is transmitted through the sealing grease 17 to the internal flow channel 23 and the annular recess 24, so as to make the pressure on both sides of the first sealing ring 4 more balanced. A third sealing ring 6 is provided on the outer periphery of the balance plug 7 to improve the sealing performance between the balance plug 7 and the sealing rod 5. In this embodiment, the internal flow channel 23 communicates with the upper space of the sealing rod 5 through the blind hole.

[0059] In some embodiments, a third shear pin 8 is provided between the push sleeve 9 and the central tube 2. The third shear pin 8 passes radially through the push sleeve 9 and partially inserts into the outer circumferential surface of the central tube 2. The third shear pin 8 can be evenly distributed circumferentially to ensure uniform circumferential force. Under the action of the third shear pin 8, the push sleeve 9 remains in its initial state. When setting is required, the setting tool applies an axial force to the push sleeve 9, and the third shear pin 8 is sheared, allowing the push sleeve 9 to move downward relative to the central tube 2 and act on the slip 10 and the rubber sleeve 12, causing the slip 10 to expand radially and the rubber sleeve 12 to expand radially, thereby achieving setting of the rubber sleeve 12.

[0060] In some embodiments, a support base 13 is provided at the lower end of the central tube 2. The upper part of the support base 13 is engaged with the outer peripheral surface of the lower end of the central tube 2, and the lower end of the sealing rod 5 is engaged with the inner peripheral surface of the lower part of the support base 13. A second shear pin 16 is provided between the sealing rod 5 and the support base 13. The support base 13 has a solvent-resistant layer only on the outer surface area other than the inner peripheral surface that engages with the central tube 2 and the sealing rod 5. Referring to Figure 1, a support base 13 is provided at the upper end of the central tube 2. The support base 13 is partially sleeved on the lower end of the central tube 2. The lower end of the sealing rod 5 is partially located in the lower end of the support base 13, and the outer peripheral surface of the sealing rod 5 and the inner peripheral surface of the support base 13 are sealed together to prevent fluid from entering between them and further into the space between the sealing rod 5 and the central tube 2. The support seat 13 is connected to the central tube 2 via a retaining pin 14. The retaining pin 14 passes through the support seat 13 and is partially inserted into the outer circumferential surface of the central tube 2 to restrict the axial relative movement and relative rotation of the support seat 13 and the central tube 2. Furthermore, the inner circumferential surface of the support seat 13 where it seals against the sealing rod 5 and the central tube 2 is not specially treated for solvent resistance; however, solvent-resistant layers are provided on other exposed surfaces to prevent accidental dissolution. When the sealing rod 5 detaches from the central tube 2, the support seat 13 begins to come into contact with the fluid and gradually dissolves. The inner diameter of the portion of the support seat 13 fitted onto the sealing rod 5 is smaller than the inner diameter of the central tube 2, thus forming a stepped surface at the lower end of the central tube 2. Correspondingly, the outer diameter of the portion of the sealing rod 5 located in the central tube 2 is smaller than the inner diameter of the portion located in the support seat 13, allowing the sealing rod 5 to be stopped against the lower end surface of the central tube 2.

[0061] In some embodiments, the sealing assembly includes two slips 10 located at both axial ends of the rubber sleeve 12. The two slips 10 are symmetrical about the rubber sleeve 12 and can be respectively engaged with the inner wall of the sleeve on both sides of the rubber sleeve 12 to ensure that the rubber sleeve 12 will not move axially under the action of external force.

[0062] In some embodiments, the sealing assembly further includes a cone 11 located between the slip 10 and the sleeve 12. The cone 11 has a tapered portion 20 that partially inserts into the slip 10. The cone 11 has a solvent-resistant layer only on its outer surface area, other than the inner circumferential surface that engages with the central tube 2. The sealing assembly includes two cones 11 located on opposite axial sides of the sleeve 12, symmetrical about the sleeve 12. The cone 11 has a tapered portion at one end facing the slip 10, which partially inserts into the slip 10. Under the axial force of the push sleeve 9 and the support of the support seat 13, the two slips 10 move relative to each other toward the sleeve 12. The tapered portions of the two cones 11 further insert into the corresponding slips 10, causing the slips 10 to expand radially and increase their overall outer diameter, thereby locking onto the inner circumferential surface of the sleeve.

[0063] The slip 10 has an opening crack and multiple compensation cracks on its outer periphery. Under the radial outward expansion of the cone 11, the slip 10 breaks at the opening crack to form a C-shaped structure and bends at the compensation cracks to form a structure with a larger outer diameter so that it can be clamped on the inner circumferential surface of the sleeve.

[0064] In some embodiments, the cone 11 has an umbrella-shaped portion 21 connected to the cone portion 20, the umbrella-shaped portion 21 forming a conical space for accommodating the insertion of a portion of the rubber tube 12. The inner diameter of the central hole of the umbrella-shaped portion 21 gradually increases in the direction toward the rubber tube 12, and it can partially accommodate the rubber tube 12, for example, the shoulder of the rubber tube 12. Such an umbrella-shaped portion 21 can limit the excessive axial expansion of the shoulders at both ends of the rubber tube 12 toward the cone 11, so that the expansion direction of the rubber tube 12 is mainly radially outward.

[0065] Furthermore, in some embodiments, the umbrella-shaped portion 21 is provided with a plurality of circumferentially spaced slits to divide the umbrella-shaped portion 21 into a plurality of umbrella petals that can be bent and deformed outwards. The umbrella-shaped portion 21 forms a plurality of umbrella petals that are relatively independent of each other, and each umbrella petal can be bent and deformed outwards. Under the expansion force of the rubber tube 12, the end of the umbrella petal facing the rubber tube 12 bends radially outwards, and finally the end of the umbrella petal facing the rubber tube 12 contacts the inner circumferential surface of the sleeve, thereby restricting the rubber tube 12 from further expanding and moving towards the cone 11.

[0066] In some embodiments, an annular groove 22 is provided on the outer periphery of the cone 11 between the conical portion 20 and the umbrella-shaped portion 21 to allow each umbrella petal to bend outward along the annular groove 22. The cone 11 is thinner at the annular groove 22, so that the umbrella petals can bend radially outward at the annular groove 22.

[0067] In some embodiments, a fourth shear pin 18 is provided between the cone 11 and the central tube 2. The fourth shear pin 18 passes radially through the cone 11 and partially inserts into the central tube 2 to achieve relative fixation between the cone 11 and the central tube 2, preventing axial movement and rotation of the cone 11 relative to the central tube 2. The fourth shear pin 18 can be evenly distributed circumferentially. Fixing the cone 11 relative to the central tube 2 can prevent the cone 11 from accidentally squeezing the rubber sleeve 12, causing the rubber sleeve 12 to be accidentally seated. When seating is required, the push sleeve 9 is pushed by the seating tool, the second shear pin 8 is sheared, the push sleeve 9 pushes the slip 10 toward the cone 11, and subsequently the fourth shear pin 18 at the cone 11 is sheared, thereby squeezing the rubber sleeve 12 by the cone 11, causing the rubber sleeve 12 to expand radially and be seated on the inner circumferential surface of the sleeve.

[0068] In some embodiments, the rubber sleeve 12 is made of soluble rubber. Soluble rubber dissolves relatively slowly, therefore no solvent-inhibiting treatment is required. During its service life, a small amount of dissolution of the rubber sleeve 12 will not affect the normal use of the bridge plug.

[0069] In some embodiments, the central tube 2 and other components of the sealing assembly, excluding the rubber sleeve 12, are made of magnesium-aluminum alloy. The solvent-resistant layer comprises a ceramic film formed by micro-arc oxidation and an organic coating. Magnesium-aluminum alloy can dissolve in a fluid environment, for example, in a solution containing chloride ions. Through the micro-arc oxidation process, a ceramic film can be formed on the surface of the magnesium-aluminum alloy. Furthermore, an organic coating is applied to the outer surface of the ceramic film to form a solvent-resistant layer through the cooperation of the ceramic film and the organic coating. This ensures that the exposed surfaces of each component are protected from premature dissolution.

[0070] In some embodiments, the organic coating is a polytetrafluoroethylene coating.

[0071] On the other hand, this solution provides a method for using the controllable total dissolution bridge plug described in the above solution, including:

[0072] Drilling begins, and the bridge plug is lowered into the oil and gas well.

[0073] A seat, which is seated in the sleeve by the seat assembly;

[0074] The pump is turned on, and the preset pressure is injected to cause the sealing rod 5 to disengage from the central tube 2;

[0075] Dissolution occurs as follows: the central tube 2 dissolves from the inside out, the seat assembly dissolves from the inside out, and the bridge plug gradually dissolves completely.

[0076] The preferred method for using the controlled total dissolution bridge plug in this scheme is as follows:

[0077] Step 1: Drilling down. Connect the upper end of the release rod of the controllable fully dissolved bridge plug to the threaded connection of the setting tool connector. After the pusher on the setting tool is installed in place, it contacts the upper end face of the pusher sleeve. Connect the upper end of the setting tool to the wellhead with a cable. Send the bridge plug and setting tool into the casing of the oil and gas well, as shown in Figure 1.

[0078] Step 2: Sealing. Following the existing sealing method, a controllable fully fused bridge plug is delivered. The pusher moves downwards under the force of the sealing tool, pushing and opening the slips symmetrically arranged around the rubber sleeve. This causes the slips to slide relative to the cone and open, locking the inner wall of the sleeve. Simultaneously, the umbrella-shaped portion on the cone opens to fill the annular gap between the bridge plug and the sleeve, further compacting the compressed rubber sleeve. The rubber sleeve is in close contact with the inner wall of the sleeve and the central tube. After reaching the predetermined load, the release lever pulls off the release pin at the upper end of the central tube, completely releasing the bridge plug. The internal channel of the central tube is sealed by the sealing rod and sealing ring. At this point, the tool completely seals the inner hole of the sleeve, as shown in Figure 2.

[0079] Step 3: Pump Start. After the wellbore operation is completed, the wellhead facilities are installed on the oil and gas well, and the pump truck is connected to pump the predetermined pressure into the wellbore. The sealing rod is subjected to downward piston force, which shears off the second shear pin. The sealing rod falls to the bottom of the well, and the internal channel of the central tube is opened. The surface area that has not been treated with surface anti-dissolution treatment comes into contact with the liquid in the well and starts to dissolve. The oil and gas well is then put into normal production by draining the fluid, as shown in Figure 3.

[0080] Step 4: Dissolution. After the oil and gas well is put into normal production, the central tube dissolves from the inside out, and the cone, slips, rubber sleeve, and support seat gradually dissolve and fail, eventually the bridge plug completely dissolves.

[0081] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0082] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A controllable full-bore bridge plug, characterized in that, The center tube (2), the seat seal assembly sealingly engaged with the outer periphery of the center tube (2), and the sealing rod (5) sealingly engaged with the inner periphery of the center tube (2), the seat seal assembly comprising the rubber sleeve (12), the slip (10) and the push sleeve (9) located at the upper part of the center tube (2), the center tube (2) and the seat seal assembly are made of soluble material, wherein the center tube (2) is provided with a dissolution-resistant layer only on the outer surface area other than the inner periphery surface engaged with the sealing rod (5), the slip (10) and the push sleeve (9) are provided with a dissolution-resistant layer only on the outer surface area other than the inner periphery surface engaged with the center tube (2), the sealing rod (5) can be separated from the center tube (2) when the upper end surface can withstand a predetermined pressure, so that the center tube (2) and the seat seal assembly can be oriented and dissolved from the inside to the outside.

2. The controllable full-bore bridge plug of claim 1, wherein, It also includes a release rod (1) partially inserted into the upper end of the center tube (2), and the release rod (1) and the center tube (2) are connected by a first shear pin (3).

3. The controllable full-bore bridge plug of claim 2, wherein, The release rod (1) is provided with a pressure transmission channel (19) extending from the outer periphery of the part of the release rod (1) outside the center tube (2) to the lower end surface.

4. The controllable full-bore bridge plug of claim 1, wherein, A first sealing ring (4) is arranged on the upper outer periphery of the sealing rod (5), a second sealing ring (15) is arranged on the lower outer periphery of the sealing rod (5), and an annular recess (24) is arranged between the first sealing ring (4) and the second sealing ring (15) on the outer periphery of the sealing rod (5), and an internal flow passage (23) is arranged in the interior of the sealing rod (5) to communicate with the annular recess (24) and the upper space of the sealing rod (5).

5. The controllable full-solution bridge plug of claim 4, wherein, The upper end surface of the sealing rod (5) is provided with a blind hole communicating with the internal flow passage (23), and the blind hole is provided with sealing grease (17) and a slidable balance plug (7) sealing the outlet of the blind hole.

6. The controllable full-bore bridge plug of claim 1, wherein, A third shear pin (8) is arranged between the push sleeve (9) and the center tube (2).

7. The controllable full-bore bridge plug of claim 1, wherein, The lower end of the center tube (2) is provided with a support seat (13), the upper part of the support seat (13) is engaged with the outer periphery of the lower end of the center tube (2), the lower end of the sealing rod (5) is engaged with the inner periphery of the lower part of the support seat (13), a second shear pin (16) is arranged between the sealing rod (5) and the support seat (13), and the support seat (13) is provided with a dissolution-resistant layer only on the outer surface area other than the inner peripheries engaged with the center tube (2) and the sealing rod (5).

8. The controllable full-bore bridge plug of claim 7, wherein, The seat seal assembly comprises two slips (10) located at the axial ends of the rubber sleeve (12).

9. The controllable full-bore bridge plug of claim 8, wherein, The seat seal assembly further comprises a cone (11) located between the slip (10) and the rubber sleeve (12), the cone (11) has a conical part (20) partially inserted into the slip (10), and the cone (11) is provided with a dissolution-resistant layer only on the outer surface area other than the inner periph-ery engaged with the center tube (2).

10. The controllable full-bore bridge plug of claim 9, wherein, The cone (11) has a umbrella-shaped part (21) connected to the conical part (20), which forms a conical space accommodating the inserted part of the rubber cylinder (12).

11. The controllable full-bore bridge plug of claim 10, wherein, The umbrella-shaped part (21) is provided with a plurality of circumferentially spaced slits to divide the umbrella-shaped part (21) into a plurality of umbrella petals capable of being deformed by bending outward.

12. The controllable full-bore bridge plug of claim 11, wherein, An annular groove (22) is provided on the outer periphery of the cone (11) between the conical part (20) and the umbrella-shaped part (21) to allow each umbrella petal to bend outward along the annular groove (22).

13. The controllable full-bore bridge plug of claim 9, wherein, A fourth shear pin (18) is provided between the cone (11) and the central tube (2).

14. The controllable full-bore bridge plug of claim 1, wherein, The rubber cylinder (12) is made of soluble rubber.

15. The controllable full-bore bridge plug of claim 1, wherein, The central tube (2) and other components of the setting assembly except the rubber cylinder (12) are made of magnesium-aluminum alloy, and the dissolution-resistant layer includes a ceramic film made by micro-arc oxidation and an organic coating.

16. The controllable full-bore bridge plug of claim 15, wherein, The organic coating is a polytetrafluoroethylene coating.

17. A method of using the controllable full-soluble bridge plug according to any one of claims 1-16, characterized in that, Comprising: Lowering the bridge plug into the oil and gas well; Setting by the setting assembly in the casing; Pump opening, pumping a preset pressure to make the sealing rod (5) separate from the central tube (2); Dissolution, the central tube (2) is dissolved from inside to outside, the setting assembly is dissolved from inside to outside, and the bridge plug is gradually completely dissolved.

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