Soluble drilling-free tapping coupling

Abstract

The invention belongs to the technical field of well cementation, and discloses a soluble drilling-free tapping coupling which comprises a casing pipe nipple connected with a casing pipe body, and a sliding sleeve is arranged in the casing pipe body in a sliding mode. The upper coupling is arranged at the joint of the casing pipe nipple and the casing pipe body; the opening sleeve and the opening cushion sleeve are arranged at the two ends of the outer side of the sleeve body respectively; the closing sleeve is arranged between the upper coupling and the opening sleeve; the first limiting piece is arranged on the sleeve body, the sliding sleeve, the opening cushion sleeve and the opening sleeve, and a protection assembly is arranged on the outer side of the first limiting piece; the protection assembly comprises an elastic gasket arranged on the outer side of the first limiting piece. The outer side of the shear pin is protected and limited through the protection assembly, the situation that the shear pin is loosened and damaged when the sleeve body vibrates and collides due to direct contact between the shear pin and the mounting hole is prevented, the stability of the shear pin in the mounting hole is improved, and the limiting effect of the shear pin is improved conveniently.

Description

Technical Field

[0001] This invention belongs to the field of cementing technology, and in particular relates to soluble, drill-free couplings. Background Technology

[0002] A staged cementing clamp, also known as a staged cementing injector, is primarily used in multi-stage cementing well cementing projects. It achieves cementing results through segmented cementing, solving the problem of poor single-stage cementing effectiveness. By dropping balls or controlling pressure, the sliding sleeve inside the staged clamp descends, opening the circulation hole, allowing cement slurry to enter the next stage of casing. The cement slurry is then injected downhole through the staged clamp, achieving staged cementing. After cementing is complete, pressure changes or other mechanisms close the staged clamp to prevent backflow of cement slurry. After the operation is finished, the inner sleeve of the staged clamp and other accessories automatically detach to the bottom of the well, eliminating the need for further drilling.

[0003] However, during use, when the casing body is lowered into the well, vibration or collision of the casing body can cause the shear pins to loosen or be damaged, causing the sliding sleeve to move prematurely and open the grouting hole, affecting the subsequent grouting effect. Summary of the Invention

[0004] To address the problems in the prior art, the present invention proposes the following technical solution: a soluble, drill-free coupling, comprising a casing short section connected to a casing body, wherein a sliding sleeve is slidably disposed inside the casing body; The upper coupling is located at the connection between the casing sub and the casing body; The opening sleeve and the opening gasket sleeve are respectively set at both ends of the outer side of the sleeve body; The closing sleeve is located between the upper coupling and the opening sleeve; The first limiting component is provided on the sleeve body, the sliding sleeve, the opening gasket sleeve and the opening sleeve, and a protective component is provided on the outside of the first limiting component. The protective components include: An elastic gasket is disposed on the outside of the first limiting member; The limiting mechanism is located on one side of the elastic gasket and is used to press against the elastic gasket.

[0005] As a preferred embodiment of the above technical solution, the casing body has a mortar injection hole at one end near the opening sleeve, the casing body and the sliding sleeve are connected through the mortar injection hole, the opening sleeve and the outside of the casing body and the closing sleeve and the outside of the casing body are slidably connected, the opening pad is located between the casing body and the closing sleeve, and the casing body has a liquid injection hole at one end near the opening pad.

[0006] As a preferred embodiment of the above technical solution, the first limiting element includes: Mounting holes are provided on the sleeve body, sliding sleeve, and opening washer sleeve; The shear pin connects to the closing sleeve, the opening sleeve, and the inner wall of the opening sleeve; the shear pin is inserted into the mounting hole.

[0007] As a preferred embodiment of the above technical solution, an installation groove is provided on the outer side of the mounting hole and on the inner wall of the opening pad, the sliding sleeve, and the sleeve body. The limiting mechanism is located in the installation groove. There are four limiting mechanisms and elastic pads, which are arranged in a circular array around the center of the scissor pin. One end of the elastic pad is located in the installation groove, and the other end is located in the mounting hole and close to the outer side of the scissor pin.

[0008] As a preferred embodiment of the above technical solution, the elastic gasket has an arc-shaped groove on the side near the shear pin, and a shearing groove is formed on the outer side of the shear pin. The shearing groove and the arc-shaped groove are arranged opposite to each other, and the elastic gasket is made of spring steel.

[0009] As a preferred embodiment of the above technical solution, the limiting mechanism includes: A gear-moving structure, set in the mounting groove, is used to limit the movement of the elastic pad; The first elastic element is connected to the gear moving structure and is used to connect the gear moving structure with the elastic pad and the inner wall of the mounting groove. A limiting rod is connected to the upper and lower sides of the gear moving structure to support the movement of the gear moving structure within the mounting slot.

[0010] As a preferred embodiment of the above technical solution, a sealing groove is provided on the inner wall of the sleeve body near the sliding sleeve, and a limiting structure is provided in the sealing groove and between the sliding sleeve and the sleeve body. The limiting structure is distributed in a ring array around the center of the sleeve body to limit the position of the sliding sleeve.

[0011] As a preferred embodiment of the above technical solution, the defined structure includes: The movable groove is formed on the inner wall of the casing body; A movable plate is connected to the outer wall of the sliding sleeve, and one end of the movable plate is slidably connected to the movable groove. A push block is connected to one side of the moving plate, and a round protrusion is connected to one side of the push block; The second limiting element is disposed on the inner wall of the sealing groove.

[0012] As a preferred embodiment of the above technical solution, the second limiting element includes: The limiting block is connected to the inner wall of the sealing groove via a telescopic rod, and the side of the limiting block near the round convex part is inclined. A limiting groove is formed on the outside of the sliding sleeve, and the limiting block is inserted into the limiting groove.

[0013] The beneficial effects of this invention are as follows: (1) This invention can be used for cementing operations in deep wells, horizontal wells, lost circulation zones, and oil layer protection. It helps to reduce the pressure difference during the cementing process and the scouring of the well wall by cement, improve the cementing quality and protect the oil layer, realize the full sealing of the open hole section, protect shallow surface water resources, and improve the high pressure bearing effect of the wellbore by closing the cement injection hole in both directions and adopting three-stage closure measures.

[0014] (2) The present invention protects and limits the outer side of the shear pin by means of a protective component, preventing the shear pin from directly contacting the mounting hole. When the sleeve body vibrates and collides, the shear pin will be loosened and damaged. This is beneficial to improving the stability of the shear pin in the mounting hole and improving the limiting effect of the shear pin. (3) The present invention limits the position of the sliding sleeve after it moves by limiting the structure between the sliding sleeve and the sleeve body and the sealing groove, preventing the sliding sleeve from moving excessively and preventing the shear pin from being deformed by additional axial tension after shearing, which would affect its use. Attached Figure Description

[0015] Figure 1 The diagram shown is a schematic representation of the overall structure of the embodiment; Figure 2 The diagram shown is a cross-sectional view of the overall structure of the embodiment; Figure 3 What is shown is Figure 2 Enlarged view of point A; Figure 4 What is shown is Figure 2 Enlarged view of point B; Figure 5 The diagram shown is a structural diagram of the shear pin and protective assembly of an embodiment; Figure 6 The diagram shown is a structural diagram of the sliding sleeve and the defined structure of the embodiment; Figure 7 The diagram shown is a structural diagram of the second limiting component of the embodiment.

[0016] In the diagram: 1. Sleeve short section; 2. Sleeve body; 3. Sliding sleeve; 4. Upper coupling; 5. Opening sleeve; 6. Opening gasket; 7. Closing sleeve; 8. Elastic gasket; 9. Filling hole; 10. Liquid filling hole; 11. Shear pin; 12. Shear groove; 13. Rack; 14. Gear; 15. First elastic element; 16. Limiting rod; 17. Sealing groove; 18. Moving plate; 19. Pushing block; 20. Round convexity; 21. Limiting block; 22. Mounting plate; 23. Telescopic rod; 24. Second elastic element; 25. Limiting groove. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0018] This invention provides a soluble, drill-free coupling, such as Figures 1 to 2As shown, the casing includes a casing sub 1, a casing body 2, a sliding sleeve 3, an upper coupling 4, an opening sleeve 5, an opening gasket 6, a first limiting component, and a protective assembly. One end of the casing sub 1 is fixedly connected to the casing body 2. The sliding sleeve 3 is slidably connected inside the casing body 2. The upper coupling 4 is fixedly connected at the connection between the casing sub 1 and the casing body 2, providing radial support to the casing body 2 through its outer diameter, ensuring the casing body 2 is centered within the wellbore. The opening sleeve 5 and the opening gasket 6 are slidably connected to the outer ends of the casing body 2, respectively. The lower opening of the opening sleeve 5 is designed as a bell-shaped opening to prevent cement slurry from forming a columnar backflow through the injection hole 9, thus effectively improving cementing quality. A closing sleeve 7 is positioned between the upper coupling 4 and the opening sleeve 5. An injection hole 9 is provided at one end of the casing body 2 near the opening sleeve 5. The casing body 2 and the sliding sleeve 3 communicate through the injection hole 9, which is used to inject mud for cementing. The opening sleeve 5 is connected to the outer ends of the casing body 2... The closing sleeve 7 and the outer side of the casing body 2 are slidably connected. The opening pad 6 is located between the casing body 2 and the closing sleeve 7. Through the cooperation of the closing sleeve 7, the opening sleeve 5, the opening pad 6, and the casing body 2, it is used to close the ash injection hole 9 of the graded clamp. The casing body 2 has a liquid injection hole 10 at one end near the opening pad 6. By changing the annular pressure, liquid can enter the inner cavity of the sliding sleeve 3 from the liquid supply hole and then flow into the oil pipe, realizing the liquid replacement between the oil pipe and the annular space. The first limiting member is set on the casing body 2, the sliding sleeve 3, the opening pad 6, and the opening sleeve 5. A protective component is set on the outer side of the first limiting member. In order to protect the shear pin 11 and reduce the vibration and collision of the shear pin 11, the protective component includes an elastic gasket 8 and a limiting mechanism. The elastic gasket 8 is set on the outer side of the first limiting member to prevent the shear pin 11 from directly contacting the inner wall of the mounting hole and causing damage to the shear pin 11. The limiting mechanism is set on one side of the elastic gasket 8 to press against the elastic gasket 8.

[0019] The first limiting component includes an installation hole and a shear pin 11. The installation hole is opened at both ends of the casing body 2. The end of the sliding sleeve 3 near the injection hole 10 is connected to the opening pad sleeve 6. The shear pin 11 is connected to the closing sleeve 7, the opening sleeve 5 and the inner wall of the opening sleeve 5. The shear pin 11 is inserted into the installation hole. When the shear pin 11 is not shearing, it keeps the seal to prevent abnormal fluid flow. When pressure is applied, the shear pin 11 breaks, making it easy to open the ash injection hole 9 for secondary cementing.

[0020] The no-drill classifier collar is attached 11 meters above the screen pipe. When used with an external packer, the classifier collar does not need to be connected to a blind plate. The function of a blind plate can be achieved by dropping a blocking ball, thus eliminating the need for drilling a blind plate (Note: the pressure of the external packer must be less than the pressure of the no-drill classifier collar, otherwise the external packer cannot be opened). Furthermore, placing the classifier collar 100-200 meters above the oil layer can significantly reduce oil layer contamination caused by the pressure difference of the cement slurry column during cementing.

[0021] When the no-drill stage hoop is inserted into the well, the closed sleeve 7, open gasket sleeve 6, and open sleeve 5 are fixed in position to the casing body 2 by shear pins 11, and the grout injection hole 9 is sealed. During the first-stage cementing operation, fluid is pumped into the casing body 2 to increase pressure. When the pressure reaches the set value (16MPa, adjustable on-site), the shear pins 11 on the open sleeve 5 are sheared, and at the same time, the open gasket sleeve 6 is elastically released, providing a smooth channel for the movement of the open sleeve 5. The open sleeve 5 moves downward under the pressure of the hydraulic column, exposing the stage hoop grout injection hole 9, opening the annulus channel, and allowing fluid to be injected into the casing body 2 and the well. Cement slurry is injected into the wall gap to complete the first stage of cementing. Before the second stage of cementing, fusible balls are inserted into the sliding sleeve 3 through the casing sub 1. The fusible balls replace the release liner to ensure no cement residue and achieve the effect of a no-drill cement plug. A gravity plug is then inserted, and 2 cubic meters of saturated brine is injected to replace the mud. After the gravity plug enters the sliding sleeve 3, the pressure is increased to 6 MPa (adjustable), and the center tube shear pin 11 is sheared, causing the sliding sleeve 3 to descend. The slurry injection hole 9 is closed, and at the same time, the fluid supply hole of the sleeve 7 is also opened, allowing the fluid to enter the inner cavity of the sliding sleeve 3 and then flow into the tubing. When the pressure of the mud column pushes the sleeve 7 to close... The shear pin 11 is cut off and moved downwards, and the injection hole 9 is closed again. At the same time, the soluble ball slides down and gradually melts, preventing the cement slurry and drilling fluid from being displaced by gravity and affecting the solidification interface. The gravity plug assembly slowly melts within a set time (within 20 hours) and sinks in a petal shape. At this time, the casing body 2 and the annulus of the well wall have completed the lower section (first stage) cementing. The stage circulation holes on the casing body 2 are in the open state, establishing an annulus channel for the second stage cementing. Relying on the circulation holes that have been opened by the stage clamp (which remain open after the first stage cementing), cement is pumped from inside the casing body 2 or the annulus. Secondary cement slurry enters the upper annulus (the section of the well that was not sealed by primary cementing) between the casing body 2 and the well wall through the staged hoop circulation hole. Secondary rubber plugs are placed and descend with the displacement fluid. After being pressed, the pressure is applied and sheared off the shear pins 11 of the casing 7, causing the staged hoop circulation hole to close and reset, ensuring that the secondary cement slurry solidifies in the annulus and does not communicate with the fluid below. After closing the circulation hole, the pressure is stabilized for a certain period of time (5 minutes). After confirming that there is no backflow, the pressure is maintained or left open for solidification, allowing the secondary cement slurry to solidify into cement stone in the annulus, sealing the upper section of the well. The staged hoop cementing is then completed.

[0022] The gravity valve is installed on the casing body 2 and is made of fusible material. Fluid flows in from the upper end of the casing body 2. When a certain pressure and flow rate are reached, the gravity valve opens by the pressure of the fluid and its own gravity, allowing the fluid to pass through smoothly. The mud scraper is made of lotus-shaped rubber. The mud scraper is powered by the mud returning from the annulus between the casing body 2 and the well wall. It moves back and forth between the upper couplings 4 of the casing body 2 to scrape and clean the well wall and the outer wall of the couplings, effectively removing mud cake. After the entire cementing process is completed, the gravity valve and the mud scraper will completely melt and sink to the bottom of the well within 15 hours, realizing unobstructed cementing of large-angle wells (above 50 degrees).

[0023] When the casing body 2 is placed in the well and vibrates or collides, the elastic gasket 8 absorbs the vibration and collision force, reduces the vibration of the shear pin 11, prevents the shear pin 11 from becoming loose or damaged, and affects the performance. When the elastic gasket 8 deforms, it squeezes the limiting mechanism, so that the limiting mechanism can press against the elastic gasket 8, so that the elastic gasket 8 is close to the shear pin 11, protects the shear pin 11, and improves the stability of the elastic gasket 8.

[0024] like Figure 2 , Figure 4 and Figure 5 As shown, mounting grooves are provided on the outer side of the mounting hole and on the inner wall of the opening pad 6, sliding sleeve 3, and sleeve body 2. The limiting mechanism is located in the mounting groove. There are four limiting mechanisms and elastic pads 8, which are arranged in a circular array around the center of the shear pin 11. One end of the elastic pad 8 is located in the mounting groove, and the other end is located in the mounting hole and close to the outer side of the shear pin 11. An arc-shaped groove is provided on the side of the elastic pad 8 near the shear pin 11. A shearing groove 12 is provided on the outer side of the shear pin 11. The shearing groove 12 is arranged opposite to the arc-shaped groove. The material of the elastic pad 8 is spring steel.

[0025] The elastic gasket 8 is model 65Mn. Through the circular array distribution of the limiting mechanism and the elastic gasket 8, the vibration generated by the sleeve body 2 can be absorbed, reducing the risk of the shear nail 11 breaking prematurely due to instantaneous impact, causing the sliding sleeve 3 to move prematurely and open the grouting hole 9, affecting the subsequent grouting effect. There is a gap of 0.1 to 0.5 mm between the elastic gasket 8 and the shear nail 11 (adjusted according to the diameter of the shear nail 11), ensuring that after deformation, the shear nail 11 can be squeezed tightly without damaging the installation hole structure. The shearing groove 12 and the arc groove make the shear nail 11 break along the circumference of the groove opening, making the fracture surface flat, ensuring that after the shear nail 11 breaks, the opening sleeve 5 and the opening gasket 6 can move smoothly.

[0026] like Figures 4 to 5 As shown, in order to improve the stability of the elastic gasket 8 and facilitate the restraint of the shear pin 11 to prevent it from loosening and affecting its use, the limiting mechanism includes a gear moving structure, a first elastic element 15, and a limiting rod 16. The gear moving structure is set in the mounting groove to limit the elastic gasket 8. The first elastic element 15 is connected to the gear moving structure to connect the gear moving structure with the elastic gasket 8 and the inner wall of the mounting groove. The limiting rod 16 is connected to the upper and lower sides of the gear moving structure to support the movement of the gear moving structure in the mounting groove.

[0027] The gear moving structure includes two racks 13, with a gear 14 meshing in the middle of the two racks 13. A rotating rod is fixedly connected to the middle of the gear 14, and both ends of the rotating rod are rotatably connected to the inner wall of the mounting groove. A first elastic element 15 is fixedly connected to one side of the rack 13. The first elastic element 15 is arranged rotationally symmetrically about the center of the gear 14. The first elastic element 15 is fixedly connected to the inner wall of the mounting groove and the elastic pad 8, respectively. The side of the two racks 13 away from the gear 14 is fixedly installed with a limiting rod 16, and the side of the limiting rod 16 away from the racks 13 is slidably connected to the inner wall of the mounting groove.

[0028] In this embodiment, the first elastic element 15 can be a compression spring. When the sleeve body 2 vibrates, causing the elastic pad 8 to deform and move, the elastic pad 8 presses against the first elastic element 15, causing the rack 13 to move into the mounting groove. The gear 14 drives the rotating rod to rotate, causing the other rack 13 meshed with the gear 14 to move towards the pad. The first elastic element 15 is stretched, causing the current rack 13 to press against the elastic pad 8, so that the elastic pad 8 can be close to the outside of the shear pin 11, protecting and limiting the outside of the shear pin 11, and improving the use effect of the shear pin 11.

[0029] like Figure 3 , Figure 6 and Figure 7 As shown, a sealing groove 17 is provided on the inner wall of the sleeve body 2 near the sliding sleeve 3. A limiting structure is provided in the sealing groove 17 between the sliding sleeve 3 and the sleeve body 2. The limiting structure is distributed in a ring array around the center of the sleeve body 2 to limit the position of the sliding sleeve 3. In order to limit the position of the sliding sleeve 3 after movement and improve the stability of the sliding sleeve 3 after movement, the limiting structure includes a moving groove, a moving plate 18, a pushing block 19, a round protrusion 20 and a second limiting member. The moving groove is opened in the inner wall of the sleeve body 2. The moving plate 18 is fixedly connected to the outer wall of the sliding sleeve 3. One end of the moving plate 18 is slidably connected in the moving groove. The pushing block 19 is fixedly connected in the moving groove. A fixed connection is made to one side of the movable plate 18, and a round protrusion 20 is fixedly connected to one side of the push block 19. A second limiting member is set on the inner wall of the sealing groove 17. The second limiting member includes a limiting block 21, a telescopic rod 23, a second elastic member 24, and a limiting groove 25. Mounting plates 22 are fixedly installed on both sides of the limiting block 21. The telescopic rod 23 and the second elastic member 24 are fixedly connected on the mounting plates 22. The limiting block 21 is connected to the inner wall of the sealing groove 17 through the telescopic rod 23 and the second elastic member 24. The side of the limiting block 21 near the round protrusion 20 is inclined. The limiting groove 25 is opened on the outside of the sliding sleeve 3. The limiting block 21 and the limiting groove 25 are inserted into each other.

[0030] In this embodiment, the second elastic element 24 can be a compression spring. The stability of the limiting block 21 during movement is improved by the telescopic rod 23 and the second elastic element 24. When the sliding sleeve 3 moves, it drives the moving plate 18, the pushing block 19 and the round protrusion 20 to move into the sealing groove 17. When the sliding sleeve 3 moves into the sealing groove 17, it closes the mortar injection hole 9. At the same time, the moving plate 18 and the pushing block 19 drive the round protrusion 20 to move along the inclined surface of the limiting block 21, squeezing the limiting block 21. This causes the telescopic rod 23 to extend and the second elastic element 24 to stretch, thereby allowing the limiting block 21 to engage with the limiting groove 25 on the sliding sleeve 3. This limits the position of the sliding sleeve 3, improves the stability of the sliding sleeve 3, ensures the stability of the opening area of ​​the mortar injection hole 9, reduces the error in the amount of cement slurry injected, improves the sealing effect, prevents cement slurry backflow and contamination, and avoids the shear nail 11 from bearing additional axial tension and reducing its service life due to the sliding sleeve 3 retraction.

[0031] Working principle: During use, the no-drill stage clamp is lowered into the well. The closing sleeve 7, opening pad sleeve 6, opening sleeve 5 and casing body 2 are fixed in position by the shear pin 11. The ash injection hole 9 is closed. The soluble ball and gravity plug assembly are inside the sliding sleeve 3 to be triggered. When the casing body 2 is placed in the well and vibrates or collides, the vibration and collision force are absorbed by the elastic pad 8, reducing the vibration of the shear pin 11. The elastic pad 8 deforms and squeezes the first elastic element 15, so that the first elastic element 15 compresses and pushes the rack 13 to move into the mounting groove. The gear 14 drives the rotating rod to rotate, so that the other rack 13 meshed with the gear 14 moves towards the pad, and stretches the first elastic element 15 connected to the rack 13, pressing against the elastic pad 8, so that the elastic pad 8 can be close to the outside of the shear pin 11, protecting and limiting the outside of the shear pin 11.

[0032] During the first-stage cementing operation, fluid is pumped into the casing body 2 to increase pressure. When the pressure reaches the set value (16MPa, adjustable on-site), the shear pins 11 on the opening sleeve 5 break along the shear groove 12, causing the shear pins 11 to be sheared off. The opening sleeve 5 is pushed downward by the fluid column pressure, exposing the staged injection hole 9 and opening the annulus channel. Cement slurry can then be injected into the gap between the casing body 2 and the wellbore, completing the first-stage cementing operation. Before the second-stage cementing, fusible balls are inserted into the sliding sleeve 3 through the casing sub 1, followed by a gravity plug. Two cubic meters of saturated brine are injected to replace the mud, and gravity is applied. After the plug enters the sliding sleeve 3, the shear pin 11 on the sliding sleeve 3 is cut by applying a pressure of 6MPa (adjustable). The sliding sleeve 3 moves downward, driving the moving plate 18, the pushing block 19, and the round protrusion 20 to move into the sealing groove 17. When the sliding sleeve 3 moves into the sealing groove 17, the moving plate 18 pushes the pushing block 19, causing the round protrusion 20 to move along the inclined surface of the limiting block 21, squeezing the limiting block 21. This causes the telescopic rod 23 to extend and the second elastic element 24 to stretch, thereby causing the limiting block 21 to engage with the limiting groove 25 on the sliding sleeve 3, limiting the position of the sliding sleeve 3 and allowing the ash to be injected. Hole 9 is closed, and simultaneously the fluid supply hole of sleeve 7 is opened, allowing fluid to enter the inner cavity of sliding sleeve 3 and then flow into the tubing. When the pressure of the mud column pushes sleeve 7 to shear the shear pin 11 downwards, it closes the ash injection hole 9 again. At the same time, the soluble ball slides down and gradually melts. The gravity plug assembly slowly melts within a set time (within 20 hours) and sinks in a petal shape. At this time, the casing body 2 and the annulus of the well wall have completed the lower section (first stage) cementing. The stage circulation holes on casing body 2 are in the open state, establishing an annulus channel for the second stage cementing. Relying on the already opened circulation holes of the stage collar... The hole (kept open after primary cementing) is pumped into the casing body 2 or annulus to inject secondary cement slurry. The cement slurry enters the upper annulus between the casing body 2 and the well wall (the section not sealed by primary cementing) through the stage hoop circulation hole. The secondary rubber plug is placed and goes down with the displacement fluid. After being pressed, the pressure is broken and the shear pin 11 on the closed casing 7 is cut off, so that the stage hoop circulation hole is closed and reset. After closing the circulation hole, the pressure is stabilized for a certain period of time (5 minutes). After confirming that there is no backflow, the pressure is maintained or left open for solidification, so that the secondary cement slurry solidifies into cement stone in the annulus, sealing the upper section of the well. The stage hoop cementing is completed.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A soluble, drill-free coupling, characterized in that, include: A sleeve short section (1) is connected to a sleeve body (2), and a sliding sleeve (3) is slidably disposed inside the sleeve body (2); an upper coupling (4) is disposed at the connection between the sleeve short section (1) and the sleeve body (2); an opening sleeve (5) and an opening pad sleeve (6) are respectively disposed at both ends of the outer side of the sleeve body (2); a closing sleeve (7) is disposed between the upper coupling (4) and the opening sleeve (5); a first limiting member is disposed on the sleeve body (2), the sliding sleeve (3), the opening pad sleeve (6) and the opening sleeve (5), and a protective component is disposed on the outer side of the first limiting member; The protective assembly includes: an elastic gasket (8) disposed on the outside of the first limiting member; a limiting mechanism disposed on one side of the elastic gasket (8) for pressing against the elastic gasket (8); the sleeve body (2) has a mortar injection hole (9) at one end near the opening sleeve (5), the sleeve body (2) and the sliding sleeve (3) are connected through the mortar injection hole (9), and the opening sleeve (5) and the outside of the sleeve body (2) and the closing sleeve (7) and the outside of the sleeve body (2) are both The sliding connection is provided, the opening pad (6) is located between the sleeve body (2) and the closing sleeve (7), and the sleeve body (2) has an injection hole (10) at one end near the opening pad (6); the first limiting member includes: an installation hole, which is opened on the sleeve body (2), the sliding sleeve (3) and the opening pad (6); and a shear pin (11), which is connected to the closing sleeve (7), the opening sleeve (5) and the inner wall of the opening sleeve (5), and the shear pin (11) is inserted into the installation hole.

2. The soluble, drill-free coupling according to claim 1, characterized in that, The mounting hole is provided with mounting grooves on the outer side of the opening pad (6), the sliding sleeve (3), and the inner wall of the sleeve body (2). The limiting mechanism is located in the mounting groove. There are four limiting mechanisms and four elastic pads (8), which are arranged in a circular array with the center of the scissor pin (11). One end of the elastic pad (8) is located in the mounting groove, and the other end is located in the mounting hole and close to the outer side of the scissor pin (11).

3. The soluble, drill-free coupling according to claim 2, characterized in that, The elastic pad (8) has an arc-shaped groove on the side near the shear pin (11), and a shearing groove (12) is provided on the outside of the shear pin (11). The shearing groove (12) is arranged opposite to the arc-shaped groove. The elastic pad (8) is made of spring steel.

4. The soluble, drill-free coupling according to claim 3, characterized in that, The limiting mechanism includes: a gear moving structure disposed in the mounting groove for limiting the elastic pad (8); a first elastic element (15) connected to the gear moving structure for connecting the gear moving structure with the elastic pad (8) and the inner wall of the mounting groove; and a limiting rod (16) connected to the upper and lower sides of the gear moving structure for supporting the gear moving structure to move within the mounting groove.

5. The soluble, drill-free coupling according to claim 4, characterized in that, A sealing groove (17) is provided on the inner wall of the sleeve body (2) near the sliding sleeve (3). A limiting structure is provided in the sealing groove (17) between the sliding sleeve (3) and the sleeve body (2). The limiting structure is arranged in a ring array around the center of the sleeve body (2) to limit the position of the sliding sleeve (3).

6. The soluble, drill-free coupling according to claim 5, characterized in that, The limiting structure includes: a movable groove, which is formed on the inner wall of the sleeve body (2); a movable plate (18), which is connected to the outer wall of the sliding sleeve (3), and one end of the movable plate (18) is slidably connected to the movable groove; a push block (19), which is connected to one side of the movable plate (18), and a round protrusion (20) is connected to one side of the push block (19); and a second limiting member, which is set on the inner wall of the sealing groove (17).

7. The soluble, drill-free coupling according to claim 6, characterized in that, The second limiting member includes: a limiting block (21), which is connected to the inner wall of the sealing groove (17) via a telescopic rod (23) and a second elastic member (24), and the limiting block (21) is inclined on the side near the round protrusion (20); a limiting groove (25), which is opened on the outside of the sliding sleeve (3), and the limiting block (21) is inserted into the limiting groove (25).

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