Back-reaming drill-free plug cementing device and staged cementing method

Abstract

This invention relates to the field of cementing technology, and is a back-insertion type no-drill plug cementing device and a staged cementing method. The former includes a central tube, an outer cylinder, a lower connector, a support compensation ring, a plug seat, a hydraulic sleeve, and an anchoring support assembly. A suspension outer ring platform is provided on the outer side of the lower end of the central tube, and an outer cylinder is provided on the outer side of the lower part of the central tube. A suspension inner ring platform is provided on the inner side of the upper end of the outer cylinder, and the lower side of the suspension inner ring platform sits on the upper side of the suspension outer ring platform. The latter has the following steps: (1) Connect the cementing operation string and run it into the well for conventional first-stage cementing operation. After the first-stage cementing operation is completed, put in the opening plug. The opening plug falls into the plug seat and sits on the upper side of the limiting ring platform, forming a seal on the upper part of the casing. The invention has a reasonable and compact structure and ingenious design. By setting the anchoring support assembly, a stable suspension effect is formed. Through the cooperation of the central tube and the hydraulic sleeve, a circulation channel for cement slurry between the casing and the annulus is formed, which has the characteristics of being fast, stable, and efficient.

Description

Technical Field

[0001] This invention relates to the field of cementing technology, specifically to a back-insertion type non-drilling plug cementing device and a staged cementing method. Background Technology

[0002] In well cementing operations, due to the excessively long cementing section and high pressure differential in some wells, the displacement pressure of general cementing equipment is insufficient to meet the construction requirements. When cementing low-pressure wells prone to leakage, an excessively long primary cementing section can lead to excessively high pressure differential, which can also easily cause well leakage. In other cases where cementing cannot be achieved due to other reasons, a staged cementing process is required. This involves using a staged cementing device to first cement the lower part, and then cementing the upper part after the cement has set. Staged cementing can effectively solve the above problems.

[0003] In the existing staged cementing device, a combination of outer shell and closing element is used to open and close the circulation hole. After the first stage of cementing is completed, the circulation hole is opened and the circulation hole on the outer shell and the closing element is aligned. Cement slurry can enter the annulus from the pipe through the circulation hole. After cementing is completed, the closing element is used to cut off the connection between the pipe and the annulus. At this time, the closing element moves down and the sealing ring moves down with it. The sealing ring cuts off the connection between the first circulation hole and the pipe, forming a complete casing.

[0004] The existing problems with staged cement injectors are as follows: (1) The sealing rings rely on accumulation for sealing, resulting in poor sealing performance, especially for gas sealing in oil and gas wells; (2) The downhole environment is harsh, with high temperature, high pressure, acid and alkali corrosion significantly damaging the sealing rings, making them unable to withstand high pressure and resulting in a short service life; (3) The sealing rings are mostly used for static friction, and when the closing parts slide downwards, they are easily sheared and damaged, leading to sealing ring failure. Therefore, in summary, the existing staged cement injectors have significant safety hazards in terms of sealing. The failure of their sealing rings can lead to cement backflow, oil and gas leakage, and even blockage of the pipe, causing major accidents such as blowouts. Summary of the Invention

[0005] This invention provides a back-insertion type non-drilling plug cement injection device and a staged cement injection method, which overcomes the shortcomings of the prior art and can effectively solve the problems of poor sealing performance of existing staged cement injection devices and cumbersome staged cementing operations.

[0006] One of the technical solutions of this invention is achieved through the following measures: a back-insertion type non-drilling cement injection device, comprising a central tube, an outer cylinder, a lower connector, a support compensation ring, a plug seat, a hydraulic sleeve, and an anchoring support assembly. A suspension outer ring platform is provided on the outer side of the lower end of the central tube, and an outer cylinder is provided on the outer side of the lower part of the central tube. A suspension inner ring platform is provided on the inner side of the upper end of the outer cylinder, with the lower side of the suspension inner ring platform seated on the upper side of the suspension outer ring platform. A lower connector is fixedly installed on the inner side of the lower end of the outer cylinder. A support compensation ring is provided on the inner side of the outer cylinder corresponding to the position between the lower end of the central tube and the upper end of the lower connector. The support compensation ring is a C-shaped ring, and at least two first shear pin holes are provided at circumferential intervals along the outer side of the upper part of the support compensation ring. At least two second shear pin holes are provided at intervals. The second shear pin holes are oblong holes with their lower ends located below the first shear pin holes. A plug seat with its lower end located below the support compensation ring is provided on the inner side of the lower end of the central tube. A first shear pin is provided in the first shear pin hole, which can fix the support compensation ring and the plug seat together. A second shear pin is provided in the second shear pin hole, which can fix the support compensation ring and the plug seat together. A limiting ring platform is provided on the inner side of the lower end of the plug seat. A hydraulic sleeve is fixedly installed on the upper end of the outer cylinder by a third shear pin. Several flow grooves with their upper ends located in the middle of the hydraulic sleeve are provided at intervals along the circumference on the outer side of the lower end of the central tube. An anchoring support assembly that can expand radially outward when subjected to an upward thrust at the lower end is fixedly installed on the upper end of the hydraulic sleeve.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned anchoring support assembly may include a coupling sleeve, an anchor claw, an anchor claw sleeve, and a support rod. An anchor claw sleeve is fixedly installed on the inner side of the upper end of the hydraulic sleeve, and a coupling sleeve is fixedly installed on the outer side of the upper part of the central tube. Several placement grooves are provided at intervals along the circumference on the outer side of the lower end of the coupling sleeve. An anchor claw with its lower end hinged to the corresponding position of the anchor claw sleeve is provided in the placement groove. The middle part of the anchor claw is hinged to the lower end of the support rod, and the upper end of the support rod is hinged to the lower end of the coupling sleeve.

[0008] The aforementioned anchoring support assembly may also include a serrated retaining ring, with a serrated retaining ring provided between the inner side of the lower end of the anchor claw sleeve and the central tube.

[0009] An arc-shaped guide surface may be provided on the inner side of the upper end of the aforementioned anchor claw.

[0010] The above may also include high-pressure sealing rings and O-rings. At least two high-pressure sealing rings are provided vertically between the inner side of the hydraulic sleeve and the outer side of the central tube above the flow channel. At least one O-ring is provided vertically between the outer side of the upper part of the plug seat and the inner side of the central tube. At least one O-ring is provided vertically between the outer side of the lower part of the plug seat and the inner side of the lower connector. At least one O-ring is provided vertically between the outer side of the outer cylinder and the inner side of the hydraulic sleeve above the third shear pin.

[0011] The above may also include a retaining ring, with a retaining ring provided on the outer side of the middle part of the suspension outer ring platform, and a retaining ring groove provided on the inner side of the lower part of the outer cylinder corresponding to the position above the lower connector.

[0012] The inner side of the upper end of the outer cylinder may be provided with a lower booster groove, which is a tapered hole that is wider at the top and narrower at the bottom. The inner side of the lower part of the hydraulic sleeve corresponding to the position of the lower booster groove is provided with an upper booster groove, which is a tapered hole that is narrower at the top and wider at the bottom.

[0013] The second technical solution of the present invention is achieved through the following measures: a graded cement injection method using the above-mentioned back-insertion type drill-free plug cement injection device, comprising the following steps: (1) Connect the cementing work string and run it into the well to carry out conventional first-stage cementing work. After the first-stage cementing work is completed, put in the opening plug. The opening plug falls into the plug seat and sits on the upper side of the limiting ring platform to form a seal on the upper part of the casing. (2) Pressurize until the first shear nail is cut off, the plug seat moves down until the second shear nail slides to the lower end of the second shear nail hole. At this time, the cement slurry flows to the hydraulic sleeve through the flow groove set at the lower end of the central tube, giving the hydraulic sleeve an upward force. When the pressure reaches the point of cutting off the third shear nail but not the second shear nail, the third shear nail is cut off, and the hydraulic sleeve moves upward. At this time, a cement slurry channel is formed from the inside of the casing to the flow groove to the hydraulic sleeve to the annulus. At the same time, the hydraulic sleeve moves upward and pushes the anchor claw sleeve to move upward. The anchor claw expands outward radially to form a well wall support. After the first-stage cementing operation is completed, the second-stage cementing operation is carried out. (3) After the cementing of the secondary cementing is completed, the shut-off plug is put in to carry out the slurry replacement operation. When the shut-off plug reaches the plug seat position, the lower end of the shut-off plug abuts against the upper end of the open plug, forming a seal on the upper part of the casing and blocking the flow groove. (4) Under the inertial force, the wellhead pressurizes instantly to the shear force of the second shearing nail and cuts off the second shearing nail. The closing plug continues to push the opening plug and plug seat downward. After losing the support of the outer wall of the plug seat, the outer diameter of the support compensation ring shrinks inward and falls into the lower connector. (5) At this time, by pressing down the entire string of casing at the wellhead, the hydraulic sleeve can be made to descend with the central tube until the hydraulic sleeve is seated at the upper end of the outer cylinder; (6) The central tube continues to descend until it sits on the upper end of the lower connector, blocking the connection between the annulus and the casing, thus closing the tool.

[0014] The present invention has a reasonable and compact structure and ingenious design. By setting up anchor support components, a stable suspension effect is formed. Through the cooperation of the central tube and the hydraulic sleeve, a circulation channel for cement slurry is formed between the inside of the sleeve and the annulus, which has the characteristics of being fast, stable and efficient. Attached Figure Description

[0015] Appendix Figure 1 These are schematic diagrams of the main cross-sectional structure of embodiments 1 to 8 of the present invention.

[0016] Appendix Figure 2 This is a schematic diagram of the front sectional structure of step (1) in Example 8.

[0017] Appendix Figure 3 This is a schematic diagram of the front sectional structure of step (2) in Example 8.

[0018] Appendix Figure 4 This is a schematic diagram of the front sectional structure of step (3) in Example 8.

[0019] Appendix Figure 5 This is a schematic diagram of the front sectional structure of step (4) in Example 8.

[0020] Appendix Figure 6 This is a schematic diagram of the front sectional structure of step (5) in Example 8.

[0021] Appendix Figure 7 This is a schematic diagram of the front sectional structure of step (6) in Example 8.

[0022] Appendix Figure 8 For the appendix Figure 1 A three-dimensional structural diagram of the central tube.

[0023] Appendix Figure 9 For the appendix Figure 1 A three-dimensional structural diagram of the central support compensation ring.

[0024] The codes in the attached diagram are as follows: 1 is the central tube, 2 is the outer cylinder, 3 is the lower connector, 4 is the support compensation ring, 5 is the plug seat, 6 is the hydraulic sleeve, 7 is the coupling sleeve, 8 is the anchor claw, 9 is the anchor claw sleeve, 10 is the support rod, 11 is the serrated snap ring, 12 is the snap ring, 13 is the suspension outer ring platform, 14 is the suspension inner ring platform, 15 is the first shear pin hole, 16 is the second shear pin hole, 17 is the limiting ring platform, 18 is the flow groove, 19 is the opening plug, 20 is the closing plug, 21 is the arc-shaped guide surface, 22 is the high-pressure sealing ring, 23 is the O-ring sealing ring, 24 is the snap ring groove, 25 is the first shear pin, 26 is the second shear pin, 27 is the third shear pin, 28 is the upper booster groove, and 29 is the lower booster groove. Detailed Implementation

[0025] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0026] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0027] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 9 As shown, the plug-in type non-drilling cement injection device includes a central tube 1, an outer cylinder 2, a lower connector 3, a support compensation ring 4, a plug seat 5, a hydraulic sleeve 6, and an anchoring support assembly. A suspension outer ring platform 13 is provided on the outer side of the lower end of the central tube 1, and an outer cylinder 2 is provided on the outer side of the lower part of the central tube 1. A suspension inner ring platform 14 is provided on the inner side of the upper end of the outer cylinder 2, with the lower side of the suspension inner ring platform 14 resting on the upper side of the suspension outer ring platform 13. A lower connector 3 is fixedly installed on the inner side of the lower end of the outer cylinder 2. A support compensation ring 4 is provided on the inner side of the outer cylinder 2 corresponding to the position between the lower end of the central tube 1 and the upper end of the lower connector 3. The support compensation ring 4 is a C-shaped ring. At least two first shear pin holes 15 are provided at intervals along the circumference on the upper outer side of the support compensation ring 4, and at least two second shear pin holes are provided at intervals along the circumference on the upper outer side of the support compensation ring 4. 16. The second shear pin hole 16 is an elongated hole with its lower end located below the first shear pin hole 15. The inner side of the lower end of the central tube 1 is provided with a plug seat 5 whose lower end is located below the support compensation ring 4. The first shear pin 25 is provided in the first shear pin hole 15, which can fix the support compensation ring 4 and the plug seat 5 together. The second shear pin hole 16 is provided with a second shear pin 26, which can install the support compensation ring 4 and the plug seat 5 together. The inner side of the lower end of the plug seat 5 is provided with a limiting ring platform 17. The upper end of the outer cylinder 2 is fixedly installed with a hydraulic sleeve 6 by a third shear pin 27. The outer side of the lower end of the central tube 1 is provided with a number of flow grooves 18 whose upper ends are located in the middle of the hydraulic sleeve 6 along the circumference. The upper end of the hydraulic sleeve 6 is fixedly installed with an anchoring support assembly that can expand radially outward when subjected to an upward thrust at the lower end.

[0028] During use, a stable suspension effect is achieved by setting up the anchoring support assembly; the cooperation between the central tube 1 and the hydraulic sleeve 6 forms a cement slurry circulation channel between the casing interior and the annulus; this embodiment is connected to the cementing operation string and lowered into the well for conventional first-stage cementing operations. After the first-stage cementing operation is completed, the opening plug 19 is inserted, and the opening plug 19 falls into the plug seat 5 and sits on the upper side of the limiting ring platform 17, forming a seal on the upper part of the casing; pressure is applied until the first shear pin 25 is sheared, and the plug seat 5 moves down until the second shear pin 26 slides to the lower end of the second shear pin hole 16. At this time, the cement slurry flows to the hydraulic sleeve 6 through the flow groove 18 set at the lower end of the central tube 1, giving the hydraulic sleeve 6 an upward force. When the pressure reaches the point where the third shear pin 27 is sheared but the second shear pin 26 is not sheared, the third shear pin 27 is sheared, and the hydraulic sleeve 6 moves upward. At this time, a cement slurry channel is formed from the casing interior to the flow groove 18 to the hydraulic sleeve 6 to the annulus. At the same time, the upward movement of the hydraulic sleeve 6 pushes the anchoring support assembly, causing the anchoring support assembly to move radially towards... The expansion extends outward to form wellbore support. After the first-stage cementing operation is completed and the cement has hardened, the second-stage cementing operation is carried out. After the second-stage cementing is completed, the closing plug 20 is inserted to perform slurry replacement. When the closing plug 20 reaches the plug seat 5, the lower end of the closing plug 20 abuts against the upper end of the opening plug 19, forming a seal on the upper part of the casing and blocking the flow channel 18. Under the inertial force, the wellhead is instantly pressurized to the shearing force of the second shear pin 26, which then shears the second shear pin 26. The closing plug 20 continues to push the opening plug 19 and the plug seat 5 downward. After losing the support of the outer wall of the plug seat 5, the outer diameter of the support compensation ring 4 narrows inward and falls into the lower connector 3. At this time, by pressing down the entire casing at the wellhead, the hydraulic sleeve 6 can be lowered with the central tube 1 until the hydraulic sleeve 6 is seated on the upper end of the outer cylinder 2. The central tube 1 continues to descend until it is seated on the upper end of the lower connector 3, sealing the connection between the annulus and the casing, thus closing the tool. This effectively solves the problems of poor sealing performance of existing staged cementing machines and cumbersome staged cementing operations. According to the requirements, the upper outer diameter of the opening plug 19 matches the upper inner diameter of the plug seat 5, and the lower outer diameter of the opening plug 19 matches the inner diameter of the lower limiting ring platform 17 of the plug seat 5; the upper outer diameter of the closing plug 20 matches the inner diameter of the central tube 1, and the lower outer diameter of the closing plug 20 matches the upper inner diameter of the plug seat 5.

[0029] The above-mentioned insertion-type drill-free cement injection device can be further optimized and / or improved according to actual needs: Example 2: As shown in the attached document Figures 1 to 9As shown, the anchoring support assembly includes a coupling sleeve 7, an anchor claw 8, an anchor claw sleeve 9, and a support rod 10. The anchor claw sleeve 9 is fixedly installed on the inner side of the upper end of the hydraulic sleeve 6, and the coupling sleeve 7 is fixedly installed on the outer side of the upper part of the central tube 1. Several placement grooves are spaced circumferentially along the outer side of the lower end of the coupling sleeve 7. Anchor claws 8, whose lower ends are hinged to the corresponding positions of the anchor claw sleeve 9, are placed in the placement grooves. The middle part of the anchor claw 8 is hinged to the lower end of the support rod 10, and the upper end of the support rod 10 is hinged to the lower end of the coupling sleeve 7. During use, by setting the hinged connection method, the anchor claw 8 can extend radially outward when the lower end of the anchor claw sleeve 9 is subjected to an upward thrust, forming a well wall support.

[0030] Example 3: As shown in the attached document Figures 1 to 9 As shown, the anchoring support assembly also includes a serrated retaining spring 11, which is provided between the inner side of the lower end of the anchor claw sleeve 9 and the central tube 1. During use, by setting the serrated retaining spring 11, the anchor claw sleeve 9 can be locked after it moves upward with the hydraulic sleeve 6, preventing the anchor claw sleeve 9 from moving downward relative to the central tube 1. In addition, the serrated retaining spring 11 can be locked at any time after it moves, providing good support for the anchor claw 8. When the central tube 1 moves downward in subsequent operations, the serrated retaining spring 11 will no longer move downward, so it can continue to push the anchor claw 8 outward, and finally anchor it in the wellbore wall.

[0031] Example 4: As shown in the appendix Figures 1 to 9 As shown, the upper inner side of the anchor claw 8 is provided with an arc-shaped guide surface 21. During use, by setting the arc-shaped guide surface 21, the anchor claw 8 is guided to expand radially outward as the anchor claw sleeve 9 and hydraulic sleeve 6 move upward; in addition, when the hydraulic sleeve 6 moves upward, it pushes the anchor claw sleeve 9 and thus pushes the anchor claw 8 to move. Under the action of the arc-shaped guide surface 21, the anchor claw 8 flips outward, and at the same time, the support rod 10 provides rigid support for the anchor claw 8. At this time, the multiple anchor claws 8 set on the outside of the central tube 1 expand and are supported on the well wall, which can make the tool be centered in the well hole, resulting in better cement injection effect.

[0032] Example 5: As shown in the attached document Figures 1 to 9As shown, it also includes a high-pressure sealing ring 22 and an O-ring 23. At least two high-pressure sealing rings 22 are provided vertically between the inner side of the middle part of the hydraulic sleeve 6 and the outer side of the central tube 1, corresponding to the position above the flow groove 18. At least one O-ring 23 is provided vertically between the outer side of the upper part of the plug seat 5 and the inner side of the central tube 1, and at least one O-ring 23 is provided vertically between the outer side of the lower part of the plug seat 5 and the inner side of the lower connector 3. At least one O-ring 23 is provided vertically between the outer side of the outer cylinder 2 and the inner side of the hydraulic sleeve 6, corresponding to the position above the third shear pin 27. During use, by setting the high-pressure sealing ring 22, the cement slurry channel between the casing and the annulus can be completely sealed when the lower end of the central tube 1 descends to the upper end of the lower connector 3; by setting the high-pressure sealing ring 22, the hydraulic sleeve 6 can be moved down with the central tube 1 by the friction of the high-pressure sealing ring 22 when the central tube 1 descends, until the hydraulic sleeve 6 is seated on the upper end of the outer cylinder 2; by setting the O-ring sealing ring 23, the stability of each component is ensured during the conventional first-stage cementing operation, as well as the stability of starting the second-stage cementing operation.

[0033] Example 6: As attached Figures 1 to 9 As shown, it also includes a retaining ring 12. A retaining ring 12 is provided on the outer side of the middle part of the suspension outer ring platform 13, and a retaining ring groove 24 is provided on the inner side of the lower part of the outer cylinder 2 corresponding to the position above the lower connector 3. During use, by setting the retaining ring 12, the retaining ring 12 can lock the central tube 1 after it moves down with the central tube 1 into the retaining ring groove 12, preventing the central tube 1 from moving upward relative to the outer cylinder 2, thus making it more difficult for the central tube 1 to separate from the outer cylinder 2, and playing a better role in high-pressure gas sealing.

[0034] Example 7: As attached Figures 1 to 9 As shown, the inner side of the upper end of the outer cylinder 2 is provided with a lower pusher groove 29, which is a tapered hole that is wider at the top and narrower at the bottom. Corresponding to the position of the lower pusher groove 29, the inner side of the lower part of the hydraulic sleeve 6 is provided with an upper pusher groove 28, which is a tapered hole that is narrower at the top and wider at the bottom. During use, by setting the upper pusher groove 28 and the lower pusher groove 29, the cement slurry helps to push the hydraulic sleeve 6 upward, causing the anchor claw 8 to expand radially outward and establish a cement slurry channel between the inside of the sleeve and the annulus.

[0035] Example 8: As attached Figures 1 to 9 As shown, a staged cement injection method using the above-mentioned insert-type drill-free cement injection device includes the following steps: (1) Connect the cementing operation string and run it into the well to carry out conventional first-stage cementing operation. After the first-stage cementing operation is completed, put in the opening plug 19. The opening plug 19 falls into the plug seat 5 and sits on the upper side of the limiting ring platform 17 to form a seal on the upper part of the casing. (2) Pressurize until the first shear nail 25 is cut, the plug seat 5 moves down until the second shear nail 26 slides to the lower end of the second shear nail hole 16. At this time, the cement slurry flows to the hydraulic sleeve 6 through the flow groove 18 set at the lower end of the central pipe 1, giving the hydraulic sleeve 6 an upward force. When the pressure reaches the point of cutting the third shear nail 27 but not the second shear nail 26, the third shear nail 27 is cut, and the hydraulic sleeve 6 moves upward. At this time, a cement slurry channel is formed from the inside of the casing to the flow groove 18 to the hydraulic sleeve 6 to the annulus. At the same time, the hydraulic sleeve 6 moves upward and pushes the anchor claw sleeve 9 to move upward. The anchor claw 8 expands outward radially to form a well wall support. After the first-stage cementing operation is completed, the second-stage cementing operation is carried out. (3) After the cementing of the secondary cementing is completed, the closing plug 20 is put in to carry out the grout replacement operation. When the closing plug 20 reaches the position of the plug seat 5, the lower end of the closing plug 20 abuts against the upper end of the opening plug 19, forming a seal on the upper part of the casing and blocking the flow groove 18. (4) Under the inertial force, the wellhead is instantly pressurized to the shear force of the second shear nail 26 and then the second shear nail 26 is cut off. The plug 20 is closed and the plug 19 and plug seat 5 are pushed down. After losing the support of the outer wall of the plug seat 5, the outer diameter of the support compensation ring 4 is reduced and it falls into the lower connector 3. (5) At this time, by pressing down the entire string of casing at the wellhead, the hydraulic sleeve 6 can be made to descend with the central pipe 1 until the hydraulic sleeve 6 sits on the upper end of the outer cylinder 2; (6) The central tube 1 continues to descend until it sits on the upper end of the lower connector 3, blocking the connection between the annulus and the sleeve, thus closing the tool.

[0036] The above technical features constitute the preferred embodiment of the present invention, which has strong adaptability and optimal implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A re-insertion type, drill-free cement injection device, characterized in that... The system includes a central tube, an outer cylinder, a lower connector, a support compensation ring, a plug seat, a hydraulic sleeve, and an anchoring support assembly. A suspension outer ring platform is located on the outer side of the lower end of the central tube, and an outer cylinder is located on the outer side of the lower part of the central tube. A suspension inner ring platform is located on the inner side of the upper end of the outer cylinder, with the lower side of the suspension inner ring platform resting on the upper side of the suspension outer ring platform. A lower connector is fixedly installed on the inner side of the lower end of the outer cylinder. A support compensation ring, a C-shaped ring, is located on the inner side of the outer cylinder corresponding to the position between the lower end of the central tube and the upper end of the lower connector. At least two first shear pin holes are spaced circumferentially on the outer side of the upper part of the support compensation ring, and at least two second shear pin holes are spaced circumferentially on the outer side of the upper part of the support compensation ring. The second shear pin holes are elongated holes with their lower ends located below the first shear pin holes. A plug seat, with its lower end located below the support compensation ring, is located on the inner side of the lower end of the central tube. A first shear pin is located in the first shear pin hole, allowing the support compensation ring to be fixedly installed with the plug seat. A second shear pin is located in the second shear pin hole, allowing the support compensation ring to be installed with the plug seat. A limiting ring platform is located on the inner side of the lower end of the plug seat. The upper end of the outer cylinder... The outer cylinder is fixedly mounted with a hydraulic sleeve by a third shear pin. Several flow grooves with their upper ends located in the middle of the hydraulic sleeve are spaced circumferentially along the outer side of the lower end of the central tube. An anchoring support assembly that expands radially outward when subjected to an upward thrust at the lower end is fixedly mounted on the upper end of the hydraulic sleeve. The anchoring support assembly includes a coupling sleeve, anchor claws, anchor claw sleeves, and a support rod. An anchor claw sleeve is fixedly mounted on the inner side of the upper end of the hydraulic sleeve, and a coupling sleeve is fixedly mounted on the outer side of the upper part of the central tube. Several placement grooves are spaced circumferentially along the outer side of the lower end of the coupling sleeve for placement... The groove is equipped with an anchor claw whose lower end is hinged to the corresponding position of the anchor claw sleeve. The middle part of the anchor claw is hinged to the lower end of the support rod, and the upper end of the support rod is hinged to the lower end of the coupling sleeve. It also includes a retaining spring. A retaining spring is provided on the outer side of the middle part of the suspension outer ring platform. A retaining spring ring groove is provided on the inner side of the lower part of the outer cylinder corresponding to the position above the lower connector. A lower booster groove is provided on the inner side of the upper end of the outer cylinder. The lower booster groove is a tapered hole that is wider at the top and narrower at the bottom. An upper booster groove is provided on the inner side of the lower part of the hydraulic sleeve corresponding to the position of the lower booster groove. The upper booster groove is a tapered hole that is narrower at the top and wider at the bottom.

2. The back-insertion type drill-free cement injection device according to claim 1, characterized in that... The anchoring support assembly also includes a serrated retaining ring, with a serrated retaining ring provided between the inner side of the lower end of the anchor claw sleeve and the central tube.

3. The re-insertion type drill-free cement injection device according to claim 2, characterized in that... An arc-shaped guide surface is provided on the inner side of the upper end of the anchor claw.

4. The insert-type drill-free cement injection device according to claim 1, 2, or 3, characterized in that... It also includes high-pressure sealing rings and O-rings. At least two high-pressure sealing rings are provided vertically between the inner side of the hydraulic sleeve and the outer side of the central tube above the flow channel. At least one O-ring is provided vertically between the outer side of the upper part of the plug seat and the inner side of the central tube. At least one O-ring is provided vertically between the outer side of the lower part of the plug seat and the inner side of the lower connector. At least one O-ring is provided vertically between the outer side of the outer cylinder and the inner side of the hydraulic sleeve above the third shear pin.

5. A method for staged cement injection using a re-insertion type drill-free cement injection device as described in any one of claims 1 to 4, characterized in that... The steps include the following: (1) Connect the cementing work string and run it into the well to carry out conventional first-stage cementing work. After the first-stage cementing work is completed, put in the opening plug. The opening plug falls into the plug seat and sits on the upper side of the limiting ring platform to form a seal on the upper part of the casing. (2) Pressurize until the first shear nail is cut, the plug seat moves down until the second shear nail slides to the lower end of the second shear nail hole. At this time, the cement slurry flows to the hydraulic sleeve through the flow groove set at the lower end of the central tube, giving the hydraulic sleeve an upward force. When the pressure reaches the point of cutting the third shear nail but not the second shear nail, the third shear nail is cut, and the hydraulic sleeve moves upward. At this time, a cement slurry channel is formed from the inside of the casing to the flow groove to the hydraulic sleeve to the annulus. At the same time, the hydraulic sleeve moves upward and pushes the anchor claw sleeve to move upward. The anchor claw expands outward radially to form a well wall support. After the first-stage cementing operation is completed, the second-stage cementing operation is carried out. (3) After the cementing of the secondary cementing is completed, the shut-off plug is put in to carry out the slurry replacement operation. When the shut-off plug reaches the plug seat position, the lower end of the shut-off plug abuts against the upper end of the open plug, forming a seal on the upper part of the casing and blocking the flow groove. (4) Under the inertial force, the wellhead pressurizes instantly to the shear force of the second shearing nail and cuts off the second shearing nail. The closing plug continues to push the opening plug and plug seat downward. After losing the support of the outer wall of the plug seat, the outer diameter of the support compensation ring shrinks inward and falls into the lower connector. (5) At this time, by pressing down the entire string of casing at the wellhead, the hydraulic sleeve can be made to descend with the central tube until the hydraulic sleeve is seated at the upper end of the outer cylinder; (6) The central tube continues to descend until it sits on the upper end of the lower connector, blocking the connection between the annulus and the casing, thus closing the tool.

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