A bridge plug

Abstract

The application discloses a bridge plug and belongs to the technical field of oil exploitation. The bridge plug comprises an outer cylinder, an anchoring sealing mechanism is arranged on the outer periphery of the outer cylinder, a floating pipe is arranged in the inner portion of the outer cylinder, the inner cavity of the floating pipe is communicated with the inner cavity of the outer cylinder to form a production channel, a sealing mechanism is arranged for sealing the production channel, the floating pipe can slide along the axial direction of the outer cylinder, a slide structure is arranged on the side wall of the floating pipe, a sliding guide is arranged in the outer cylinder, the sliding guide is in sliding cooperation with the slide structure, the slide structure is provided with a first sliding end point and a second sliding end point, when the sliding guide is located at the first sliding end point, the production channel is sealed, when the sliding guide is located at the second sliding end point, the production channel is unsealed, a spring is arranged between the floating pipe and the outer cylinder, one end of the spring is connected with the floating pipe, and the other end of the spring is connected with the outer cylinder. The bridge plug can realize well killing-free operation, the opening and closing control of the production channel is very convenient, the production efficiency can be improved, and the operation risk can be reduced.

Description

Technical Field

[0001] This application relates to the field of oil extraction technology, and more specifically, to a bridge plug. Background Technology

[0002] Currently, fracturing technology is widely used in tight oil and gas reservoirs, shale oil and gas reservoirs, and coalbed methane. The most widely used fracturing process is the bridge plug perforation combined operation technique. After fracturing, there are three main options: 1) direct production via casing; 2) running production tubing under pressure; and 3) well control using high-density kill fluid to achieve wellhead depressurization. However, all these methods have certain drawbacks and well control risks. Option 1, direct production via casing, causes significant damage to the casing and is rarely used now. Option 2 is currently the most common method, but it has a long construction period, high well control risks, and is expensive. Option 3 is relatively low-cost, but the high-density kill fluid causes significant formation damage and severely impacts production. After well control, running production tubing under conventional methods carries high well control risks and is prone to blowouts. Summary of the Invention

[0003] This application aims to provide a bridge plug that addresses the problem of high well control risk after fracturing in existing technologies.

[0004] A bridge plug includes: an outer cylinder with an anchoring and sealing mechanism disposed on its outer periphery; a floating tube disposed inside the outer cylinder and coaxially arranged with the outer cylinder, the inner cavity of the floating tube communicating with the inner cavity of the outer cylinder to form a production channel; and a sealing mechanism disposed inside the outer cylinder for isolating the inner cavity of the floating tube from the inner cavity of the outer cylinder to seal the production channel. The floating tube can slide axially relative to the outer cylinder to release the closure mechanism from the production channel. A slide rail structure is provided on the side wall of the floating tube, and a sliding guide is provided inside the outer cylinder. The sliding guide partially extends into the slide rail structure and slides in cooperation with it. The slide rail structure has at least a first sliding end point and a second sliding end point, and the first and second sliding end points are at different axial positions on the floating tube. When the sliding guide is located at the first sliding end point, the production channel is closed; when the sliding guide is located at the second sliding end point, the production channel is unclosed. A spring is also provided between the floating tube and the outer cylinder. One end of the spring is connected and fixed to the floating tube, and the other end of the spring is connected and fixed to the outer cylinder.

[0005] Optionally, the sealing mechanism includes a first sealing structure and a second sealing structure; the first sealing structure is disposed at the first end of the floating tube, and the second sealing structure is disposed at the second end of the floating tube.

[0006] Optionally, the first sealing structure includes a first sealing ball; a first sealing surface is formed on the inner side of the first end of the floating tube, the first sealing ball is movably disposed in the outer cylinder, and the first sealing ball abuts against the first sealing surface.

[0007] Optionally, a stop block is provided in the outer cylinder corresponding to the first sealing ball. The stop block is located at the end of the first sealing ball away from the floating tube, and the first sealing ball can move axially between the stop block and the first end of the floating tube.

[0008] Optionally, a first liquid flow hole is provided on the side wall of the second end of the floating tube, and the first liquid flow hole communicates with the inner cavity of the floating tube; the second sealing structure includes a sealing sleeve, a first sealing ring and a second sealing ring; the sealing sleeve is disposed on the inner wall of the outer cylinder and fitted onto the outer periphery of the second end of the floating tube, the first liquid flow hole is located inside the sealing sleeve, and the first sealing ring and the second sealing ring tightly fill the space between the sealing sleeve and the floating tube, and along the axial direction of the floating tube, the first sealing ring and the second sealing ring are respectively located at both ends of the first liquid flow hole.

[0009] Optionally, the second sealing structure further includes a second sealing ball, which is connected to the second end of the floating tube. A second sealing surface is formed on the inner side of the end of the sealing sleeve, and the second sealing ball abuts against the second sealing surface.

[0010] Optionally, a fixing ring is provided on the floating tube, and the spring is sleeved on the outer periphery of the floating tube. One end of the spring is connected to the fixing ring, and the other end of the spring is connected to the sealing sleeve.

[0011] Optionally, the slide structure includes a first slide, a second slide, and a third slide; The first slide and the second slide are spaced apart, and the length of the first slide is greater than the length of the second slide. Both the first slide and the second slide include an open end and a blind end. The open ends of the first slide and the open ends of the second slide are aligned. The blind ends of the first slide and the blind ends of the second slide extend to different positions along the axial direction of the floating tube. The blind end of the first slide is the first sliding end point, and the blind end of the second slide is the second sliding end point. The third slide is located at the opening end of the first slide and the second slide, and the third slide connects the first slide and the second slide. The sliding guide can switch between the first slide and the second slide via the third slide.

[0012] Optionally, a switching guide is provided at the connection between the third slide and the first slide, and at the connection between the third slide and the second slide, wherein the extension direction of the switching guide is arranged at an angle to the axial direction of the floating tube.

[0013] Optionally, a plurality of first slides and a plurality of second slides are distributed at intervals along the circumference of the floating tube, and the first slides and the second slides are arranged alternately; a plurality of third slides are continuously distributed along the circumference of the floating tube.

[0014] Beneficial effects: The bridge plug described in this application, by setting an anchoring and sealing mechanism on the outer periphery of the outer cylinder, can anchor the bridge plug in the casing during operation and seal the gap between the bridge plug and the casing. By setting a sealing mechanism inside the outer cylinder, the inner cavity of the outer cylinder can be isolated from the inner cavity of the floating tube, thereby sealing the production channel and ultimately sealing the wellbore. This completely seals the bottom hole pressure, leaving the wellhead pressure-free, enabling pressure-free well operations, effectively protecting the oil and gas reservoir, and reducing the risks and economic losses of traditional construction operations. By setting up a floating tube, a slide structure, and a sliding guide, and using external hydraulic pressure as a drive, the axial sliding of the floating tube relative to the outer cylinder can be controlled. With the elastic restoring effect of the spring, the sliding guide can be restricted to the first or second sliding end point, thereby locking the relative position of the floating tube and the outer cylinder. This realizes the sealing mechanism's sealing or unsealing of the production channel, ultimately achieving on / off control of the production channel, improving the convenience of operation and increasing production efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the bridge plug structure proposed in one embodiment of this application; Figure 2 This is a partially enlarged schematic diagram of the upper half of the bridge plug according to an embodiment of this application; Figure 3 This is a partially enlarged schematic diagram of the lower half of the bridge plug according to an embodiment of this application; Figure 4 This is a planar unfolded schematic diagram of the slide rail structure on the floating tube in a bridge plug according to an embodiment of this application; Figure 5 This is a schematic diagram of the slip structure of a bridge plug according to an embodiment of this application; Figure 6 This is a schematic diagram of the connection structure between the bridge plug seat, pusher, and adapter according to an embodiment of this application.

[0017] Explanation of reference numerals in the attached figures: 1. Outer cylinder; 11. Hand release ring; 111. Shear weakness structure; 12. Well washing sleeve; 121. Stop block; 122. Second fluid flow hole; 123. Third fluid flow hole; 13. Sealing center tube; 14. Transformer joint; 15. Connecting sleeve; 151. Retaining ring; 16. Spring sleeve; 17. Lower joint; 2. Floating tube; 21. First flow hole; 22. Fixed ring; 3. Anchoring and sealing mechanism; 30. Limiting ring; 311. Upper slip; 3110. Hard alloy post; 312. Upper cone; 313. Upper shear pin; 321. Lower slip; 322. Lower cone; 323. Lower shear pin; 331. Upper rubber sleeve; 332. Intermediate rubber sleeve; 333. Lower rubber sleeve; 341. Upper protective cover; 342. Lower protective cover; 4. First sealing structure; 41. First sealing ball; 5. Second sealing structure; 51. Sealing sleeve; 52. Second sealing ball; 521. Countersunk hexagonal groove; 6. Slide structure; 61. First slide; 62. Second slide; 63. Third slide; 64. Switching guide; 7. Sliding guide; 71. Rotating ring; 72. Guide post; 8. Spring; 001, First sealing ring; 002, Second sealing ring; 003, Third sealing ring; 004, Fourth sealing ring; 005, Fifth sealing ring; 006, Sixth sealing ring; 007, Seventh sealing ring; 008, Eighth sealing ring; 009, Ninth sealing ring; A. First taxiing end point; B. Second taxiing end point; C. Third taxiing blind end; D. Push tube; E. Adapter. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] Among related technologies, fracturing technology has been widely applied to tight oil and gas reservoirs, shale oil and gas reservoirs, and coalbed methane. Currently, the most widely used fracturing process is the bridge plug perforation combined operation technology. After fracturing, there are three main options: 1) direct production via casing; 2) running production tubing under pressure; and 3) well control using high-density kill fluid to achieve wellhead depressurization. Currently, all these methods have certain shortcomings and well control risks. Option one, direct production via casing, causes significant damage to the casing and is rarely used now. Option two is currently the most common method, but it has a long construction period, high well control risks, and is expensive. Option three is relatively low-cost, but the high-density kill fluid causes significant formation damage and severely impacts production. After well control, running production tubing under conventional methods carries high well control risks and is prone to blowouts.

[0020] In view of this, embodiments of this application propose a bridge plug.

[0021] A bridge plug includes: an outer cylinder 1, wherein an anchoring and sealing mechanism 3 is provided on the outer periphery of the outer cylinder 1; a floating tube 2, disposed inside the outer cylinder 1 and coaxially arranged with the outer cylinder 1, wherein the inner cavity of the floating tube 2 is interconnected with the inner cavity of the outer cylinder 1 to form a production channel; and a sealing mechanism, disposed inside the outer cylinder 1, for isolating the inner cavity of the floating tube 2 from the inner cavity of the outer cylinder 1 to seal the production channel. The floating tube 2 can slide axially relative to the outer cylinder 1 to release the closure mechanism from the production channel. A slide rail structure 6 is provided on the side wall of the floating tube 2, and a sliding guide 7 is provided inside the outer cylinder 1. The sliding guide 7 partially extends into the slide rail structure 6 and slides in cooperation with it. The slide rail structure 6 has at least a first sliding endpoint A and a second sliding endpoint B, with the first sliding endpoint A and the second sliding endpoint B having different axial positions on the floating tube 2. When the sliding guide 7 is located at the first sliding endpoint A, the production channel is closed; when the sliding guide 7 is located at the second sliding endpoint B, the production channel is unclosed. A spring 8 is also provided between the floating tube 2 and the outer cylinder 1. One end of the spring 8 is connected and fixed to the floating tube 2, and the other end of the spring 8 is connected and fixed to the outer cylinder 1.

[0022] Specifically, the bridge plug includes an outer cylinder 1 and a floating tube 2 coaxially positioned within and coaxial with the outer cylinder 1. An anchoring and sealing mechanism 3 is installed on the outer periphery of the outer cylinder 1. During operation, the bridge plug is delivered to a predetermined position in the wellbore using a cable or tubing string. Pressure generated by explosive detonation, hydraulic setting, or mechanical setting tools acts on the anchoring and sealing mechanism 3, causing it to deform and expand outward, thereby anchoring itself to the inner wall of the casing and sealing the gap between the bridge plug and the casing. The inner cavity of the outer cylinder 1 and the inner cavity of the floating tube 2 are interconnected to form a production channel. A sealing mechanism is installed inside the outer cylinder 1, which isolates the inner cavity of the outer cylinder 1 from the inner cavity of the floating tube 2, thus sealing the production channel. Therefore, the wellbore can be sealed through the anchoring and sealing mechanism 3 and the sealing mechanism, completely sealing the bottom hole pressure and placing the wellhead in a pressureless state, enabling pressure-free well operations, effectively protecting the oil and gas reservoir, and reducing well control risks.

[0023] The floating tube 2 can slide axially relative to the outer cylinder 1. In actual operation, the floating tube 2 can be driven to slide axially in the first direction by applying pressure through an external hydraulic device. During the sliding process of the floating tube 2, the relative position of the floating tube 2 and the outer cylinder 1 changes, and the state of the closing mechanism changes accordingly. Therefore, by controlling the axial position of the floating tube 2 relative to the outer cylinder 1, the closure mechanism can be used to close or release the production channel, thereby realizing the control of the closure and opening of the production channel.

[0024] Specifically, a slide rail structure 6 is provided on the side wall of the floating tube 2, and a sliding guide 7 is provided inside the outer cylinder 1. A portion of the sliding guide 7 extends into the slide rail structure 6. When the floating tube 2 slides relative to the outer cylinder 1, the sliding guide 7 slides relative to it within the slide rail structure 6. Through the cooperation between the sliding guide 7 and the slide rail structure 6, the sliding distance of the floating tube 2 relative to the outer cylinder 1 can be limited. The slide rail structure 6 has at least two sliding endpoints, namely a first sliding endpoint A and a second sliding endpoint B. The axial positions of the first sliding endpoint A and the second sliding endpoint B on the floating tube 2 are different. When the sliding guide 7 is at the first sliding endpoint A, the floating tube 2 is at the first target position relative to the outer cylinder 1, and the closed structure is in working condition, with the production channel completely closed. When the sliding guide 7 is at the second sliding endpoint B, the floating tube 2 is at the second target position relative to the outer cylinder 1, and the closed structure is in non-working condition, with the production channel unclosed.

[0025] A spring 8 is provided between the floating tube 2 and the outer cylinder 1. One end of the spring 8 is connected to the floating tube 2, and the other end of the spring 8 is connected to the outer cylinder 1. The spring 8 is used to provide elastic force when the external hydraulic equipment is depressurized, so as to drive the floating tube 2 to slide along the second axial direction, that is, the opposite direction to the first direction, and finally restrict the sliding guide 7 at the first sliding end point A or the second sliding end point B, thereby locking the relative position of the floating tube 2 and the outer cylinder 1, so that the production channel can still be maintained in the closed or open state after the external hydraulic equipment is depressurized.

[0026] With the above configuration, the opening and closing control of the production channel is simple and convenient, thanks to the cooperation of the floating tube 2, the slide structure 6, the sliding guide 7 and the spring 8, which helps to reduce the difficulty of operation and improve production efficiency.

[0027] Optionally, the sealing mechanism includes a first sealing structure 4 and a second sealing structure 5; the first sealing structure 4 is disposed at the first end of the floating tube 2, and the second sealing structure 5 is disposed at the second end of the floating tube 2.

[0028] See Figure 2 and Figure 3 The sealing mechanism includes a first sealing structure 4 and a second sealing structure 5, wherein the first sealing structure 4 is disposed at the first end of the floating tube 2, that is... Figure 1 The upper end of the floating tube 2 shown has a second sealing structure 5 located at the second end, i.e. Figure 1 The lower end of the floating tube 2 shown can be sealed by setting a first sealing structure 4 and a second sealing structure 5 at the upper and lower ends of the floating tube 2 respectively, thereby achieving the separation between the inner cavity of the floating tube 2 and the inner cavity of the outer cylinder 1.

[0029] Optionally, the first sealing structure 4 includes a first sealing ball 41; a first sealing surface is formed on the inner side of the first end of the floating tube 2, and the first sealing ball 41 is movably disposed in the outer cylinder 1, with the first sealing ball 41 abutting against the first sealing surface.

[0030] Specifically, such as Figure 2 As shown, the first sealing structure 4 includes a first sealing ball 41, which is movably disposed inside the outer cylinder 1 and located at the upper end of the floating tube 2. A first sealing surface is formed on the inner side of the upper end of the floating tube 2. Under the action of gravity, the first sealing ball 41 can abut against the first sealing surface, thereby achieving a seal on the upper end of the floating tube 2. Preferably, the first sealing surface is set as an inclined surface, which can increase the contact area with the first sealing ball 41, making the contact between the two tighter and helping to improve the reliability of the seal.

[0031] Optionally, a stop 121 is provided in the outer cylinder 1 corresponding to the first sealing ball 41. The stop 121 is located at the end of the first sealing ball 41 away from the floating tube 2, and the first sealing ball 41 can move axially between the stop 121 and the first end of the floating tube 2.

[0032] Specifically, a stop 121 is provided in the outer cylinder 1. The stop 121 is located at the upper end of the first sealing ball 41. The distance between the bottom end of the stop 121 and the bottom end of the first sealing surface should be greater than the diameter of the first sealing ball 41 to ensure that the first sealing ball 41 can move axially between the stop 121 and the end of the floating pipe 2. When the production channel is closed, the first sealing ball 41 is pressed against the first sealing surface by gravity. When the floating pipe 2 slides downward until the second sealing structure 5 releases the seal on the lower end of the floating pipe 2, under the reservoir pressure of the oil and gas layer, the oil and gas enter the inner cavity of the floating pipe 2 through the lower end of the floating pipe 2, and then reach the upper end of the floating pipe 2. The first sealing ball 41 moves upward against its own gravity under the pressure of the oil and gas until it separates from the first sealing surface. Thus, the seal on the upper end of the floating pipe 2 is also released, and the oil and gas can continue to be transported to the ground along the pipeline through the upper end of the floating pipe 2 to complete the oil and gas collection. By setting the stop 121, the limit position of the upward movement of the first sealing ball 41 can be restricted when the production channel is opened, so as to prevent the first sealing ball 41 from being pushed out of the outer cylinder 1 under oil and gas pressure.

[0033] Optionally, a first liquid flow hole 21 is provided on the side wall of the second end of the floating tube 2, and the first liquid flow hole 21 communicates with the inner cavity of the floating tube 2; the second sealing structure 5 includes a sealing sleeve 51, a first sealing ring 001 and a second sealing ring 002; the sealing sleeve 51 is disposed on the inner wall of the outer cylinder 1 and fitted on the outer periphery of the second end of the floating tube 2, the first liquid flow hole 21 is located inside the sealing sleeve 51, the first sealing ring 001 and the second sealing ring 002 are tightly filled between the sealing sleeve 51 and the floating tube 2, and along the axial direction of the floating tube 2, the first sealing ring 001 and the second sealing ring 002 are respectively located at both ends of the first liquid flow hole 21.

[0034] For details, see Figure 3One or more first liquid flow holes 21 are provided on the lower side wall of the floating tube 2. The first liquid flow holes 21 are connected to the inner cavity of the floating tube 2, serving as the inlet and outlet of the lower end of the inner cavity of the floating tube 2. The second sealing structure 5 includes a sealing sleeve 51, a first sealing ring 001, and a second sealing ring 002. The sealing sleeve 51 is fitted between the outer cylinder 1 and the floating tube 2. The outer wall of the sealing sleeve 51 and the inner wall of the outer cylinder 1 can be connected and fixed by a threaded fit. The inner wall of the sealing sleeve 51 is in close contact with the outer wall of the floating tube 2 and completely covers the first liquid flow hole 21. A sealing groove is provided on the inner wall of the sealing sleeve 51. The first sealing ring 001 and the second sealing ring 002 are installed in the sealing groove and tightly fill the gap between the sealing sleeve 51 and the floating tube 2, forming the first sealing barrier at the lower end of the floating tube 2. Along the axial direction of the floating tube 2, the positions of the first sealing ring 001 and the second sealing ring 002 are respectively on the upper and lower sides of the first liquid flow hole 21, which can ensure the sealing effect of the first liquid flow hole 21.

[0035] When the floating tube 2 slides downward under the drive of external hydraulic force, the floating tube 2 slides downward relative to the sealing sleeve 51. The first liquid flow hole 21 gradually emerges from the sealing sleeve 51 as the floating tube 2 slides, connecting the inner cavity of the lower end of the outer cylinder 1 with the inner cavity of the floating tube 2, thereby releasing the seal at the lower end of the floating tube 2.

[0036] Optionally, the second sealing structure 5 further includes a second sealing ball 52, which is connected to the second end of the floating tube 2. A second sealing surface is formed on the inner side of the end of the sealing sleeve 51, and the second sealing ball 52 abuts against the second sealing surface.

[0037] Specifically, to further improve the sealing reliability of the lower end of the floating tube 2, the second sealing structure 5 also includes a second sealing ball 52. The second sealing ball 52 is connected to the lower end of the floating tube 2, and a second sealing surface is formed on the inner side of the lower end of the sealing sleeve 51. The second sealing ball 52 and the second sealing surface are tightly fitted together to form a second sealing barrier at the lower end of the floating tube 2, further ensuring the sealing performance. Preferably, the second sealing surface is set as an inclined surface, which can increase the contact area with the second sealing ball 52, making the contact between the two tighter and helping to improve the sealing reliability.

[0038] For ease of assembly, in this embodiment, the second sealing ball 52 is detachably connected to the lower end of the floating tube 2. The connecting shaft of the second sealing ball 52 extends into the interior of the lower end of the floating tube 2, and the outer wall of the connecting shaft of the second sealing ball 52 is threaded into the inner wall of the lower end of the floating tube 2 to achieve connection. Furthermore, a countersunk hexagonal groove 521 is also provided on the second sealing ball 52 to facilitate assembly with tools.

[0039] Optionally, a fixing ring 22 is provided on the floating tube 2, and the spring 8 is sleeved on the outer periphery of the floating tube 2. One end of the spring 8 is connected to the fixing ring 22, and the other end of the spring 8 is connected to the sealing sleeve 51.

[0040] Specifically, a fixing ring 22 is provided on the outer periphery of the floating tube 2. The inner wall of the fixing ring 22 is fixed to the outer wall of the floating tube 2 by a threaded connection. A spring 8 is fitted on the outer periphery of the floating tube 2. One end of the spring 8 is connected and fixed to the fixing ring 22, and the other end is connected and fixed to the sealing sleeve 51. The spring 8 is in a compressed state. When the floating tube 2 slides downward relative to the outer cylinder 1 under the pressure of the external hydraulic equipment, the spring 8 is further compressed. When the external hydraulic equipment is depressurized, the spring 8 can provide elastic force to drive the floating tube 2 to slide upward to the first target position or the second target position.

[0041] Optionally, the slide structure 6 includes a first slide 61, a second slide 62, and a third slide 63; The first slide rail 61 and the second slide rail 62 are spaced apart, and the length of the first slide rail 61 is greater than the length of the second slide rail 62. Both the first slide rail 61 and the second slide rail 62 include an open end and a blind end. The open end of the first slide rail 61 and the open end of the second slide rail 62 are aligned. The blind end of the first slide rail 61 and the blind end of the second slide rail 62 extend to different positions along the axial direction of the floating tube 2. The blind end of the first slide rail 61 is the first sliding end point A, and the blind end of the second slide rail 62 is the second sliding end point B. The third slide 63 is disposed at the opening end of the first slide 61 and the second slide 62. The third slide 63 connects the first slide 61 and the second slide 62. The sliding guide 7 can switch between the first slide 61 and the second slide 62 via the third slide 63.

[0042] For details, see Figure 4 The slide structure 6 includes a first slide 61, a second slide 62, and a third slide 63. Each of the first slide 61, the second slide 62, and the third slide 63 has an open end and a blind end. The first slide 61 and the second slide 62 are spaced apart and extend upward along the axial direction of the floating tube 2. The open end of the first slide 61 is flush with the open end of the second slide 62, and the blind ends of the first slide 61 and the second slide 62 extend toward the second end of the floating tube 2. The third slide 63 is positioned at the interval between the first slide 61 and the second slide 62. The open end of the third slide 63 faces and communicates with the open ends of the first slide 61 and the second slide 62, and the blind end of the third slide 63 extends toward the first end of the floating tube 2.

[0043] The blind end of the first slide 61 is the first sliding endpoint A, and the blind end of the second slide 62 is the second sliding endpoint B. Since the length of the first slide 61 is greater than the length of the second slide 62, the first sliding endpoint A is closer to the second end of the floating tube 2 than the second sliding endpoint B. Figure 1 The lower end of the floating tube 2 shown is in the first target position relative to the outer cylinder 1 when the sliding guide 7 is located at the first sliding end point A. When the sliding guide 7 is located at the second sliding end point B, the floating tube 2 is in the second target position relative to the outer cylinder 1. The second target position is lower than the first target position.

[0044] Since the third slide 63 connects the first slide 61 and the second slide 62 simultaneously, the sliding guide 7 can switch between the first slide 61 and the second slide 62 through the third slide 63.

[0045] Optionally, a switching guide 64 is provided at the connection between the third slide 63 and the first slide 61, and at the connection between the third slide 63 and the second slide 62. The extension direction of the switching guide 64 is arranged at an angle to the axial direction of the floating tube 2.

[0046] Specifically, to improve the smoothness of switching slides, switching guides 64 are provided at the connection points between the third slide 63 and the first slide 61, and at the connection points between the third slide 63 and the second slide 62. The switching guides 64 are inclined relative to the axis of the floating tube 2. Two switching guides 64 are configured for each third slide 63, and the two switching guides 64 are respectively connected to the first slide 61 and the second slide 62 corresponding to that third slide 63.

[0047] The axial position of the sliding guide 7 is fixed. When the floating tube 2 slides axially relative to the outer cylinder 1, the position of the sliding guide 7 in the slide rail structure 6 changes. Specifically, when the floating tube 2 is in the first target position, the sliding guide 7 is at the blind end of the first slide rail 61, that is... Figure 4At the first sliding endpoint A, when the external hydraulic pressure drives the floating tube 2 to slide down, the sliding guide 7 slides relative to the floating tube 2 toward the open end of the first slide rail 61. When it reaches the switching guide 64 on one side of the third slide rail 63, due to the inclined setting of the switching guide 64, the slide guide rotates a certain angle around the circumference under the pushing and guiding action of the switching guide 64, thus smoothly entering the third slide rail 63 and temporarily stopping at the blind end C of the third slide rail. When the external hydraulic equipment is depressurized, the floating tube 2 slides upward under the elastic force of the spring 8, and the sliding guide 7 slides relative to the floating tube 2 toward the open end of the third slide rail 63. When it reaches the switching guide 64 on the other side of the third slide rail 63, the slide guide rotates a certain angle around the circumference under the pushing and guiding action of the switching guide 64, and then enters the second slide rail 62, stopping at the blind end of the second slide rail 62, that is, at the second sliding endpoint B.

[0048] Each time the sliding guide 7 slides into or out of the third slide rail 63, it rotates circumferentially by a certain angle. By providing an inclined switching guide 64, the sliding guide 7 can rotate smoothly, thereby achieving the switching of the slide rail. The inclination angle of the switching guide 64 can be set as needed. As an optional implementation, in this embodiment, the angle between the extension direction of the switching guide 64 and the axis of the floating tube 2 is set to 30°, and the angle between the two switching guides 64 configured in the same third slide rail 63 is 60°.

[0049] Optionally, a plurality of first slide rails 61 and a plurality of second slide rails 62 are distributed at intervals along the circumference of the floating tube 2, and the first slide rails 61 and the second slide rails 62 are arranged alternately; a plurality of third slide rails 63 are continuously distributed along the circumference of the floating tube 2.

[0050] Specifically, multiple first slide rails 61, second slide rails 62, and third slide rails 63 are provided along the circumference of the floating tube 2. Figure 4 The diagram shows a planar unfolded schematic of the slide structure 6. The number of first slides 61 and second slides 62 is the same, and they are distributed at equal intervals in a staggered arrangement. The number of third slides 63 is equal to the sum of the number of first slides 61 and second slides 62. Adjacent third slides 63 are connected to each other, resulting in a continuous distribution of multiple third slides 63 around the circumference of the floating tube 2. Figure 4 As shown, in this embodiment, the number of first slide rails 61 and second slide rails 62 are both set to two, the central angle corresponding to the interval between adjacent first slide rails 61 and second slide rails 62 is 90°, and the number of third slide rails 63 is set to four.

[0051] Optionally, the sliding guide 7 includes a rotating ring 71 and a guide post 72. The rotating ring 71 is rotatably disposed inside the outer cylinder 1, and the guide post 72 is fixedly installed inside the rotating ring 71, with a portion of the guide portion extending into the slide rail structure 6 for sliding engagement. The rotating ring 71 can rotate circumferentially relative to the outer cylinder 1, thus providing the guide post 72 with circumferential rotational freedom, allowing the guide post 72 to smoothly switch slide rails. Furthermore, a retaining ring 151 is provided at the lower end of the rotating ring 71, which can axially limit the sliding guide 7.

[0052] Optionally, for ease of assembly, in this embodiment, the outer cylinder 1 adopts a multi-segment split structure, see [reference]. Figure 2 and Figure 3 The outer cylinder 1 includes a release ring 11, a well-washing sleeve 12, a sealing center tube 13, a conversion joint 14, a connecting sleeve 15, a spring sleeve 16, and a lower joint 17 connected in sequence. The floating tube 2 is placed inside the well-washing sleeve 12, the sealing center tube 13, the connecting sleeve 15, and the sealing sleeve 51, and can achieve axial sliding.

[0053] Specifically, the upper end of the release ring 11 is provided with a threaded hole for connecting with the matching setting tool. The release ring 11 and the well washing sleeve 12 are connected by a connecting plate and a shear pin. The connecting plate and the shear pin form a shear weakness structure 111, which can be disconnected when the setting force reaches a certain value, thereby completing the release action.

[0054] One or more second fluid flow holes 122 are provided on the side wall of the well-washing sleeve 12. A stop block 121 is disposed inside the well-washing sleeve 12, and one or more third fluid flow holes 123 are provided in the stop block 121. The second fluid flow holes 122 and the third fluid flow holes 123 are simultaneously connected with the inner cavity of the well-washing sleeve 12 to form a well-washing channel, which facilitates the flow of fluid during well washing. The floating pipe 2 is sealed to the well-washing sleeve 12 by a third sealing ring 003.

[0055] The sealing center tube 13 is threaded to the lower end of the well washing sleeve 12. A limit ring 30 is fitted on the upper end of the sealing center tube 13. The lower end of the sealing center tube 13 extends into the conversion joint 14 and is threaded to the conversion joint 14. The sealing center tube 13 and the conversion joint 14 are sealed by the fourth sealing ring 004. The outer periphery of the sealing center tube 13 is used to fit the anchoring sealing mechanism 3.

[0056] The connecting sleeve 15 is threaded to the lower end of the conversion joint 14. The connecting sleeve 15 and the floating tube 2 are sealed by the fifth sealing ring 005, and the connecting sleeve 15 and the conversion joint 14 are sealed by the sixth sealing ring 006. The sliding guide 7 is disposed inside the connecting sleeve 15.

[0057] The spring sleeve 16 is threaded to the lower end of the connecting sleeve 15 and is sealed to the connecting sleeve 15 by the seventh sealing ring 007. The spring 8 is placed inside the spring sleeve 16.

[0058] The upper and lower ends of the sealing sleeve 51 are threadedly connected to the spring sleeve 16 and the lower connector 17, respectively, and are sealed to the spring sleeve 16 and the lower connector 17 by the eighth sealing ring 008 and the ninth sealing ring 009, respectively.

[0059] Optionally, the anchoring sealing mechanism 3 includes a dual anchoring assembly and an expansion sealing assembly, see [link to documentation]. Figure 2 The dual anchoring assembly includes a first anchor and a second anchor. The first anchor and the second anchor have the same structure and are installed symmetrically at the upper and lower ends of the expansion seal assembly. Specifically, the first anchoring component includes an upper slip 311 and an upper cone 312. The upper cone 312 is arranged with its pointed end facing upwards. The upper cone 312 is connected to the sealing center tube 13 by an upper shear pin 313. The upper slip 311 is fitted onto the upper part of the upper cone 312. The upper end of the upper slip 311 abuts against the limiting ring 30, and the lower end abuts against the side of the upper cone 312. The second anchoring component includes a lower slip 321 and a lower cone 322. The lower cone 322 is arranged with its pointed end facing downwards. The lower cone 322 is connected to the sealing center tube 13 by a lower shear pin 323. The lower slip 321 is fitted onto the lower part of the lower cone 322. The upper end of the lower slip 321 abuts against the side of the lower cone 322, and the lower end abuts against the adapter 14. The expansion seal is located between the first anchor and the second anchor. The expansion seal adopts a rubber tube structure, which can expand and deform towards the middle when both ends are squeezed.

[0060] During setting, the setting pressure acts downward on the anchoring sealing mechanism 3, shearing off the upper shear pin 313 and the lower shear pin 323. The anchoring sealing mechanism 3 moves downward relative to the sealing center tube 13, and the upper slip 311 and lower slip 321 expand and rupture outward along the inclined surfaces of the upper cone 312 and the lower cone 322, respectively, thereby anchoring to the inner wall of the sleeve. At the same time, the first anchoring member and the second anchoring member squeeze the rubber sleeve structure towards the center, causing it to expand and deform towards the center, thereby sealing the gap between the bridge plug and the sleeve.

[0061] Figure 5 The diagram shows the structure of the upper slip 311. The upper slip 311 adopts an anchoring method using embedded hard alloy posts 3110, and has multiple stress grooves along the circumference to allow it to break and expand along the stress groove direction during setting, thus achieving smooth anchoring. The lower slip 321 has the same structure as the upper slip 311, but is installed in the opposite direction.

[0062] Optionally, the rubber sleeve structure specifically includes an upper rubber sleeve 331, an intermediate rubber sleeve 332, and a lower rubber sleeve 333 connected in sequence. An upper protective cover 341 is provided between the upper rubber sleeve 331 and the upper cone 312, and a lower protective cover 342 is provided between the lower rubber sleeve 333 and the lower cone 322. By providing the upper protective cover 341 and the lower protective cover 342, the rubber sleeve structure can be protected to a certain extent, avoiding premature deformation of the rubber sleeve structure during the process of sending the bridge plug into the wellbore, which would affect the normal setting of the seal.

[0063] Optionally, the side of the upper protective cover 341 facing the upper rubber cylinder 331 and the side of the lower protective cover 342 facing the lower rubber cylinder 333 are both set as inclined surfaces. The inclined surfaces are inclined outward from the end of the rubber cylinder structure to the middle of the rubber cylinder structure. By setting the inclined surfaces, a certain guiding role can be played when the rubber cylinder structure is squeezed, so as to ensure the accuracy of the deformation direction and expansion part of the rubber cylinder structure.

[0064] In this embodiment, the rubber sleeve structure and sealing ring are both made of rubber, the spring 8 is made of 60Si2Mn alloy spring steel, and the remaining parts are all made of composite materials, which facilitates subsequent drilling and grinding.

[0065] The bridge plug provided in this embodiment is lowered into the wellbore using a cable delivery method. (See [link to documentation]). Figure 6 The tubing structure, from bottom to top, consists of a bridge plug, pusher cylinder D, adapter E, cable seat and cable, with the cable extending to the wellhead.

[0066] The process of using the bridge plug provided in this embodiment is as follows: Sealing process: After the bridge plug is lowered to the designed position, the cable seater is activated. The cable seater generates a downward thrust through the explosion of gunpowder. This downward thrust acts on the limiting ring 30, upper slip 311, upper cone 312, upper protective cover 341, upper rubber sleeve 331, intermediate rubber sleeve 332, lower rubber sleeve 333, lower protective cover 342, lower cone 322, and lower slip 321, thereby shearing the upper shear pin 313 and lower shear pin 323, and activating the sealing mechanism. The setting and anchoring sealing mechanism 3 moves downward relative to the sealing center tube 13. The upper slip 311 and the lower slip 321 expand outward along the inclined surfaces of the upper cone 312 and the lower cone 322, respectively, and break along the set stress groove to achieve expansion sealing and anchoring to the inner wall of the sleeve. At the same time, under the compression of the upper and lower cones and the upper and lower slips, the upper rubber sleeve 331, the middle rubber sleeve 332 and the lower rubber sleeve 333 expand outward to seal to the inner wall of the sleeve, thus completing the setting and sealing process.

[0067] Release process: As the sealing force continues to rise, since the anchoring and sealing mechanism 3 has completed anchoring and sealing, when the sealing force reaches the shear force of the shear weak point structure 111, the shear weak point structure 111 breaks, and the release of the bridge plug and cable seater is completed. The cable, cable seater, pusher D and adapter E are then extracted.

[0068] Running the production tubing: After the setting seal is released, the wellbore is now completely sealed, the bottom hole pressure is completely sealed, and the wellhead is pressureless. The production tubing can then be run in using conventional operating methods.

[0069] Production channel opening process: Connect external hydraulic equipment to apply positive pressure to the bridge plug. The pressure is transmitted to the first sealing ball 41, which pushes the floating tube 2 downward. The floating tube 2 drives the fixed ring 22 to compress the spring 8. Since the guide column 72 is located at the first sliding end point A before entering the well, when the floating tube 2 moves downward, the guide column 72 moves upward relative to the first sliding end point A along the first slide 61. During this process, the second sealing ball 52 separates from the sealing sleeve 51, the second sealing barrier fails, and the first fluid flow hole 21 at the lower end of the floating tube 2 is exposed outside the sealing sleeve 51. The first sealing barrier also fails. When the guide column 72 slides to the blind end C of the third slide, the preparation for switching forward is completed. Subsequently, the external hydraulic equipment is depressurized. Under the elastic force of the spring 8, the fixed ring 22 is pushed upward, driving the floating tube 2 upward. The guide column 72 enters the second slide 62 from the third slide 63 and finally stops at the second sliding end point B. At this time, the opening of the production channel is completed.

[0070] Production channel closure process: When the production channel needs to be closed later, the operation method is similar to the opening process. First, positive pressure is applied by the external hydraulic equipment, the floating tube 2 slides downward, and the guide column 72 slides from the second sliding end point B along the second slide rail 62 into the third slide rail 63. When it reaches the blind end C of the third slide rail, the preparation for switching forward is completed. Then, the external hydraulic equipment is depressurized, and under the elastic force of the spring 8, the floating tube 2 moves upward, and the guide column 72 enters the first slide rail 61 from the third slide rail 63, and finally stops at the first sliding end point A, completing the closure of the production channel.

[0071] Compared to existing technologies, the bridge plug provided in this embodiment is made of composite material, eliminating the need for subsequent retrieval measures. It can be removed through drilling and milling, thus avoiding later accidents. The double-slip, double-cone anchoring method improves anchoring performance and ensures better sealing performance. The top of the bridge plug is equipped with a well-washing channel, which can prevent the production channel from being unable to open due to sand accumulation. The coordinated arrangement of the sliding guide 7, the slide structure 6, and the spring 8 makes the opening and closing control of the production channel very convenient. The lower end of the floating pipe 2 adopts a spherical steel body sealing structure and a double seal of sealing rubber to ensure the complete sealing of the production channel.

[0072] The bridge plug provided in this embodiment is mainly used for sealing the channel after fracturing in oil, water, and gas wells. The bridge plug is lowered into the wellbore via cable and reliably seated in the wellbore using a cable seater. This enables the sealing of the pressurized wellbore after fracturing. The production channel can be opened hydraulically, enabling pressure-free well operations, effectively protecting the oil and gas reservoir, reducing the risks and economic losses of traditional construction operations, and improving production efficiency.

[0073] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0074] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. In the absence of further restrictions, an element defined by the phrase "includes a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0075] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A bridge plug, characterized in that, include: The outer cylinder is provided with an anchoring and sealing mechanism on its outer periphery; A floating tube is disposed inside the outer cylinder and arranged coaxially with the outer cylinder. The inner cavity of the floating tube is interconnected with the inner cavity of the outer cylinder to form a production channel. A sealing mechanism is provided inside the outer cylinder to isolate the inner cavity of the floating tube from the inner cavity of the outer cylinder so that the production channel is sealed off; The floating tube can slide axially relative to the outer cylinder to release the closure mechanism from the production channel. A slide rail structure is provided on the side wall of the floating tube, and a sliding guide is provided inside the outer cylinder. The sliding guide partially extends into the slide rail structure and slides in cooperation with it. The slide rail structure has at least a first sliding end point and a second sliding end point, and the first and second sliding end points are at different axial positions on the floating tube. When the sliding guide is located at the first sliding end point, the production channel is closed; when the sliding guide is located at the second sliding end point, the production channel is unclosed. A spring is also provided between the floating tube and the outer cylinder. One end of the spring is connected and fixed to the floating tube, and the other end of the spring is connected and fixed to the outer cylinder.

2. The bridge plug according to claim 1, characterized in that: The sealing mechanism includes a first sealing structure and a second sealing structure; the first sealing structure is disposed at the first end of the floating tube, and the second sealing structure is disposed at the second end of the floating tube.

3. The bridge plug according to claim 2, characterized in that: The first sealing structure includes a first sealing ball; A first sealing surface is formed on the inner side of the first end of the floating tube, and the first sealing ball is movably disposed in the outer cylinder, with the first sealing ball and the first sealing surface abutting against each other.

4. The bridge plug according to claim 3, characterized in that: A stop block is provided in the outer cylinder corresponding to the first sealing ball. The stop block is located at the end of the first sealing ball away from the floating tube, and the first sealing ball can move axially between the stop block and the first end of the floating tube.

5. The bridge plug according to claim 2, characterized in that: A first liquid flow hole is provided on the side wall of the second end of the floating tube, and the first liquid flow hole communicates with the inner cavity of the floating tube. The second sealing structure includes a sealing sleeve, a first sealing ring, and a second sealing ring; The sealing sleeve is disposed on the inner wall of the outer cylinder and fitted onto the outer periphery of the second end of the floating tube. The first liquid flow hole is located inside the sealing sleeve. The first sealing ring and the second sealing ring are tightly filled between the sealing sleeve and the floating tube, and along the axial direction of the floating tube, the first sealing ring and the second sealing ring are respectively located at both ends of the first liquid flow hole.

6. The bridge plug according to claim 5, characterized in that: The second sealing structure further includes a second sealing ball, which is connected to the second end of the floating tube. A second sealing surface is formed on the inner side of the end of the sealing sleeve, and the second sealing ball abuts against the second sealing surface.

7. The bridge plug according to claim 5, characterized in that: A fixing ring is provided on the floating tube, and the spring is sleeved on the outer circumference of the floating tube. One end of the spring is connected to the fixing ring, and the other end of the spring is connected to the sealing sleeve.

8. The bridge plug according to claim 1, characterized in that: The slide structure includes a first slide, a second slide, and a third slide; The first slide and the second slide are spaced apart, and the length of the first slide is greater than the length of the second slide. Both the first slide and the second slide include an open end and a blind end. The open ends of the first slide and the open ends of the second slide are aligned. The blind ends of the first slide and the blind ends of the second slide extend to different positions along the axial direction of the floating tube. The blind end of the first slide is the first sliding end point, and the blind end of the second slide is the second sliding end point. The third slide is located at the opening end of the first slide and the second slide, and the third slide connects the first slide and the second slide. The sliding guide can switch between the first slide and the second slide via the third slide.

9. The bridge plug according to claim 8, characterized in that: A switching guide is provided at the connection between the third slide and the first slide, and at the connection between the third slide and the second slide. The extension direction of the switching guide is arranged at an angle to the axial direction of the floating tube.

10. The bridge plug according to claim 8 or 9, characterized in that: Multiple first slides and multiple second slides are distributed at intervals along the circumference of the floating tube, and the first slides and second slides are arranged alternately; multiple third slides are continuously distributed along the circumference of the floating tube.

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