Rotary cement breaker tool and pull and push sleeve construction process

Abstract

The application relates to the technical field of abandoned well casing recovery operation, in particular to a rotary rolling cement breaking tool and a casing replacement construction process, wherein the tool comprises a main shaft provided with rollers, a movable roller and rollers in sequence along an axial direction, a piston and a centralizer are oppositely arranged in the inner side of the movable roller in the side wall of the main shaft; a fluid channel is arranged in the main shaft; a lower joint is sleeved on the tail end of the main shaft through screw threads, a pressure regulating channel is arranged in the lower joint; a plurality of top blocks capable of elastically sliding along the radial direction of the main shaft are inserted into the lower joint along the circumferential direction of the main shaft, the top blocks can be outwardly stretched and locked on the inner wall of the casing under the action of hydraulic pressure; the tail end of the fluid channel is in a flared structure along the flow direction; a plug rod is arranged in the pressure regulating channel, the end of the plug rod facing the fluid channel is in a conical structure and is inserted into the tail end of the fluid channel. Therefore, the setting of the sensing mechanism can sense the moment when the cement ring at the segmented position of the target casing section is completely destroyed, so that the termination time of the extrusion operation can be determined.

Description

Technical Field

[0001] This invention relates to the field of abandoned well casing recovery technology, and in particular to a rotary compactor cement crusher and casing replacement construction process. Background Technology

[0002] As oil and gas well development enters its mid-to-late stages, oil and gas resources gradually deplete. When the oil and gas production in the well drops to a level with no economic value or when further extraction is no longer possible, the well will face permanent abandonment. Well abandonment is the final stage in the entire lifecycle of oil and gas development, and its quality directly affects ecological and environmental safety; therefore, it must be carried out in strict accordance with industry standards.

[0003] According to industry standards, when abandoning a well, the casing must be cut, retrieved, and recovered layer by layer at a suitable well depth, and then the wellbore must be sealed with cement to effectively isolate the residual oil and gas in the well and prevent leakage and environmental pollution. During the initial cementing process, the cement slurry solidifies and binds the inner casing, cement sheath, outer casing, and formation together. Although this ensures wellbore stability during the production period, it increases the casing pull-out resistance during well abandonment, hindering the progress of the abandonment operation.

[0004] To address the difficulty in pulling out casing, related technologies, such as Chinese patent CN112610177B, disclose a squeezing device for recovering abandoned well casing. This device mainly utilizes the combined action of high-pressure liquid and squeezing rings to break the bonding surface between the cement layer and the casing, thus solving the problem of difficult casing extraction and achieving efficient casing recovery.

[0005] However, the aforementioned extrusion device used for well casing recovery cannot determine the degree of cement sheath breakage in real time during well casing recovery operations, making it difficult to determine when to terminate the extrusion operation. If it is terminated too early, the cement sheath will not be completely broken, and the gap between the casing and the cement sheath will be insufficient, which will still not effectively reduce the pull-out resistance. If the operation is overdone, it will increase the operation time and energy consumption, and further aggravate the risk of casing damage. Summary of the Invention

[0006] Therefore, it is necessary to provide a rotary compaction cement crushing tool and a casing replacement construction process to address the problem of low operation efficiency caused by the inability to judge the degree of cement sheath breakage and determine the timing of extrusion termination during the current abandoned well casing recovery operation.

[0007] The above objectives are achieved through the following technical solutions:

[0008] A rotary compactor for cement breaking includes a main shaft capable of both rotation and axial movement. Two rollers are axially spaced on the main shaft to maintain its centered position during operation. A movable roller is also mounted on the main shaft between the two rollers. A piston and a centralizer are disposed opposite each other inside the movable roller on the side wall of the main shaft. A fluid channel is provided within the main shaft. When liquid is injected into the main shaft through the fluid channel, under hydraulic pressure, the piston drives the movable roller to move radially, deviating from the axis of the main shaft. After the hydraulic pressure dissipates, the centralizer drives the piston and movable roller to return to their original positions. The main shaft has a threaded lower connector at its end, which has a pressure regulating channel that communicates with the fluid channel and the internal cavity of the sleeve. Several top blocks are inserted into the lower connector along the circumference of the main shaft. The top blocks can slide elastically along the radial direction of the main shaft and can extend outward and be rubbed and locked onto the inner wall of the sleeve under hydraulic pressure. The end of the fluid channel has a flared structure along the flow direction. The pressure regulating channel has an insert rod, which has a tapered structure at the end facing the fluid channel and gradually expands along the flow direction of the fluid channel before being inserted into the end of the fluid channel.

[0009] Furthermore, the taper at the end of the fluid channel is equal to the taper at the tapered end of the insert.

[0010] Furthermore, a protective sleeve is fitted at the end of the spindle and outside the lower connector, forming a sealed chamber between the protective sleeve, the spindle, and the lower connector, with the threaded sections of the spindle and the lower connector located within the sealed chamber.

[0011] Furthermore, the protective sleeve and the spindle can be detachably connected.

[0012] Furthermore, the protective sleeve is detachably attached to the end of the spindle by screws.

[0013] Furthermore, there are multiple moving rollers, which are arranged axially, and the eccentric directions of different moving rollers are offset along the circumferential direction of the main shaft.

[0014] Furthermore, there are three or more moving rollers, and the two outermost moving rollers replace two other rollers.

[0015] Furthermore, there are four moving rollers.

[0016] This invention also provides a sleeve replacement construction process, which employs a rotary compactor cement crusher. The sleeve replacement construction process includes the following steps:

[0017] Segmented casing cutting: The casing cutting tool is lowered to the target casing segment, and the target casing segment is cut into segments using the casing cutting tool;

[0018] Tool Change: Remove the casing cutting tool, and then lower the rotary compactor cement breaker to the target casing section;

[0019] Cement crushing: Indirectly crushes cement rings by rotating and compacting cement crushing tools;

[0020] Tool replacement: Remove the rotary compactor cement breaker, and then lower the retrieval tool to the target casing section;

[0021] Casing retrieval: The cut target casing sections are retrieved separately using retrieval tools.

[0022] Furthermore, prior to the casing retrieval step, the following steps are also included:

[0023] Enlarging the sleeve coupling: Lower the enlarging tool to the sleeve coupling position and enlarge the sleeve coupling position accordingly.

[0024] The beneficial effects of this invention are:

[0025] This invention relates to a rotary compaction cement crushing tool and a sleeve replacement construction process. By setting a top block and an insert rod, and utilizing the characteristics of the insert rod having a conical structure at one end facing the fluid channel and the fluid channel having a flared structure at the end along the flow direction, during the cement ring crushing process, when the cement ring at the segment of the target sleeve is completely destroyed, the segment of the target sleeve rotates synchronously with the main shaft under the frictional locking between the top block and the inner wall of the sleeve. At this time, the depth of the insert rod tip inserted into the end of the fluid channel remains unchanged, and the liquid pressure in the fluid channel tends to stabilize, indicating that the cement ring at the segment of the target sleeve has been completely destroyed. This facilitates determining the termination time of the compaction operation, avoiding premature termination, incomplete cement ring crushing, and insufficient gap between the sleeve and the cement ring, which still cannot effectively reduce the pull-out resistance. It also avoids over-operation, which increases operating time and energy consumption, and further exacerbates the risk of sleeve damage, thus improving overall operating efficiency. Attached Figure Description

[0026] Figure 1 A three-dimensional structural diagram of the rotary compactor cement breaking tool provided in an embodiment of the present invention when it is located inside the casing;

[0027] Figure 2 This is a front view of the rotary compactor cement breaking tool provided in an embodiment of the present invention when it is located inside the casing.

[0028] Figure 3 A top view of the rotary compactor cement breaking tool provided in an embodiment of the present invention when it is located inside the casing;

[0029] Figure 4 for Figure 3 Sectional view along the AA direction;

[0030] Figure 5 for Figure 4A magnified schematic diagram of the structure at point W in the middle;

[0031] Figure 6 for Figure 4 A magnified schematic diagram of the structure at point X in the middle;

[0032] Figure 7 A three-dimensional cross-sectional view of the rotary compactor cement breaking tool provided in an embodiment of the present invention when it is located inside the casing;

[0033] Figure 8 for Figure 7 A magnified schematic diagram of the structure at point Y in the middle;

[0034] Figure 9 This is a three-dimensional structural diagram of the rotary compactor cement breaking tool provided in an embodiment of the present invention when it operates inside a casing.

[0035] Figure 10 This is a top view of the rotary compactor cement breaking tool provided in an embodiment of the present invention during operation inside a casing.

[0036] Figure 11 for Figure 10 Sectional view along the BB direction;

[0037] Figure 12 for Figure 11 A magnified schematic diagram of the structure at point Z in the middle.

[0038] in:

[0039] 1. Spindle; 101. Fluid passage; 102. Piston bore; 103. Alignment hole; 104. Limiting boss;

[0040] 2. Moving roller; 201. Moving roller housing; 202. Thrust bearing B; 203. Radial bearing B; 204. Torque sleeve;

[0041] 3. Lower connector; 301. Pressure regulating channel; 302. Throttling chamber; 303. Slot; 304. First ring platform;

[0042] 4. Limiting block B;

[0043] 5. Piston;

[0044] 6. Centralizer; 601. Centralizer block; 602. First spring;

[0045] 7. Top block; 701. Rod-shaped part; 702. Arc-shaped part;

[0046] 8. The second spring;

[0047] 9. Insert rod; 901. Connecting groove; 902. Connecting hole;

[0048] 10. Retaining ring;

[0049] 11. Protective cover; 1101. Second ring platform. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage," unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They 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 limiting the invention.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] The existing cement breaking tool includes a main shaft 1, two rollers sleeved on the main shaft 1 and spaced apart along the axial direction of the main shaft 1, a movable roller 2 sleeved on the main shaft 1 and located between the two rollers, and a lower connector 3 threaded to the end of the main shaft 1.

[0054] The main shaft 1 can move along its own axis to facilitate inserting the sleeve during operation and pulling it out of the sleeve after operation, and it can also rotate around its own axis to facilitate the rotation of other parts, thereby facilitating the application of lateral force to the sleeve through the moving roller 2 to rotate and crush the cement.

[0055] For ease of description, the two rollers are named the upper roller and the lower roller, respectively. The upper roller includes an upper roller housing, which is a cylindrical structure with open ends. Thrust bearings A are provided between the inner sides of both ends of the upper roller housing and the main shaft 1. A radial bearing A is provided between the inner side of the middle part of the upper roller housing and the main shaft 1. The two ends of the upper roller housing are axially limited on the main shaft 1 by limiting blocks A and limiting rings, respectively. The limiting rings are located at the shoulders of the main shaft 1.

[0056] The lower roller includes a lower roller housing, which is a cylindrical structure with open ends. Thrust bearings C are provided between the inner sides of both ends of the lower roller housing and the main shaft 1. A radial bearing C is provided between the inner side of the middle part of the lower roller housing and the main shaft 1. The two ends of the lower roller housing are axially limited on the main shaft 1 by limiting protrusions and limiting blocks C on the main shaft 1, respectively. The limiting protrusions are annular structures.

[0057] The movable roller 2 includes a movable roller housing 201, which is a cylindrical structure with open ends. Thrust bearings B202 are provided between the inner sides of both ends of the movable roller housing 201 and the main shaft 1. A radial bearing B203 is provided between the inner side of the middle part of the movable roller housing 201 and the main shaft 1. The two ends of the movable roller housing 201 are axially limited on the main shaft 1 by limiting blocks B4 and limiting protrusions, respectively.

[0058] Limiting blocks A, B4, and C can all be configured as annular structures, and each of them has screw holes through its peripheral sidewalls that mate with screw holes on the main spindle 1, so that they can be fixed to the main spindle 1 by screw connection to achieve axial limiting.

[0059] An upper crushing band is provided on the outer peripheral wall of the upper roller housing; a lower crushing band is provided on the outer peripheral wall of the lower roller housing; and a moving roller crushing band is provided on the outer peripheral wall of the moving roller housing 201. The upper crushing band, the lower crushing band, and the moving roller crushing band all utilize their special alloy tooth structure to crush and impact the cement ring rather than grind it, causing it to crack and break, thereby facilitating the release of the cement from the casing.

[0060] Under the limiting action of the limiting ring and limiting block A, the upper roller housing, upper crushing band, radial bearing A, and thrust bearing A form a whole, together constituting the upper roller. Similarly, under the limiting action of the limiting block C and the limiting protrusion, the lower roller housing, lower crushing band, radial bearing C, and thrust bearing C form a whole, together constituting the lower roller.

[0061] A fluid channel 101 is provided inside the main shaft 1. The fluid channel 101 is located in the middle of the main shaft 1 and extends along the axial direction of the main shaft 1, passing through both ends of the main shaft 1, for the passage of liquid (such as hydraulic oil). On the side wall of the main shaft 1, at the location of the moving roller 2, there is a row of piston holes 102 arranged at intervals along the axial direction of the main shaft 1. The piston holes 102 extend radially along the main shaft 1 and communicate with the fluid channel 101 to receive liquid and facilitate the transmission of hydraulic pressure. A piston 5 is slidably inserted into each piston hole 102. A torque sleeve 204 is provided between the radial bearing B203 and the main shaft 1. The torque sleeve 204 has a cylindrical structure, and its two ends are axially limited by two thrust bearings B202 respectively, and simultaneously contact the inner ring of the radial bearing B203 and the piston 5. When hydraulic oil enters the piston hole 102, under the action of hydraulic pressure, the piston 5 moves outward along the piston hole 102, synchronously pushing the moving roller 2 to make an eccentric motion.

[0062] Under the limiting action of the limiting protrusion and the limiting block B4, the moving roller housing 201, the moving roller crushing belt, the thrust bearing B202, the radial bearing B203, and the torque sleeve 204 form a whole, together constituting the moving roller 2.

[0063] On the side wall of the main shaft 1, a row of centering holes 103 are provided at intervals along the axial direction of the main shaft 1 at the location of the moving roller 2. The centering holes 103 and the piston holes 102 are arranged opposite to each other. A centering device 6 is inserted into each centering hole 103. The centering device 6 includes a centering block 601 and a first spring 602. One end of the first spring 602 is located at the bottom of the centering hole 103, and the other end is located on the centering block 601. The centering block 601 is in direct contact with the inner ring of the radial bearing B203 to achieve radial limiting of the moving roller 2.

[0064] The lower connector 3 has a pressure regulating channel 301 that communicates with the fluid channel 101 and the internal cavity of the sleeve. The pressure regulating channel 301 is located in the middle of the lower connector 3 and extends along the axial direction of the main shaft 1, with a circular cross-section. The lower connector 3 also has a throttling cavity 302 that communicates with the fluid channel 101 and the pressure regulating channel 301. The throttling cavity 302 has a constricted structure and gradually narrows along the flow direction of the fluid channel 101. In use, the working pressure of the tool is adjusted by changing the diameter of the pressure regulating channel 301. When the total area of ​​the piston 5 is constant, the total lateral thrust of the piston 5 on the moving roller 2 generated by the radial movement of the piston 5 under hydraulic action is proportional to the working pressure.

[0065] During well abandonment operations, the cement breaking tool is first lowered from the top of the casing to the target casing section. Then, hydraulic oil is injected into the fluid channel 101. The hydraulic oil flows into the casing cavity through the throttling chamber 302 and the pressure regulating channel 301, and also flows into the piston hole 102. Under hydraulic pressure, the piston 5 slides outward, and the piston 5 simultaneously pushes the moving roller 2, making it eccentrically positioned with the main shaft 1. As the moving roller 2 moves, it simultaneously drives the centralizing block 601 to move inward, and the first spring 602 is compressed and stores energy. When the moving roller... 2. After contacting the inner wall of the casing, the drilling rig drives the main shaft 1 to rotate and move axially. When the main shaft 1 rotates, it synchronously drives the moving roller 2 to rotate eccentrically. Since the moving roller 2 is equipped with a radial bearing B203, the moving roller 2 "rolls" against the inner wall of the casing in a rolling contact manner, causing the casing to undergo elastic deformation, thereby destroying the cement ring at the circumferential position of the moving roller 2. When the main shaft 1 moves axially, it synchronously drives the moving roller 2 to move axially, destroying the cement ring at the axial position, until the cement ring in the entire target casing section is completely destroyed.

[0066] Once the cement ring at the entire target casing section is completely destroyed, the hydraulic pressure is released, the first spring 602 is released, and the driving roller 2 is reset.

[0067] In an eccentric state, the moving roller 2 rotates and moves axially simultaneously under the drive of the main shaft 1. Its force state can be simplified as follows: the radial reaction force of the sleeve on the moving roller 2 is transmitted sequentially by the moving roller crushing band to the moving roller housing 201, the radial bearing B203, and then to the piston 5 through the torque sleeve 204. The piston 5 itself only bears radial force. The axial reaction force from the sleeve on the moving roller 2 due to the axial movement of the main shaft 1 is first transmitted to the moving roller housing 201 via the moving roller crushing band, and then to the bearings located at both ends of the moving roller 2. The thrust bearing B202 then transmits the axial force reaction force to the limiting protrusion, and finally to the spindle 1. The torque sleeve 204 is used to bear the torque applied to the cement breaking tool by the drilling rig. The torque of the cement breaking tool during operation can reach tens of thousands of Newton-meters, and the axial force can reach several tons or even tens of tons. If the piston 5 bears huge torque and bearing force at the same time, it will inevitably reduce the service life of the piston 5. The torque sleeve 204 can protect the piston 5 and prevent it from bearing high torque, thereby extending the service life of the tool.

[0068] While the above process can break the cement ring of the target casing section, the lack of feedback and adjustment procedures during the operation makes it impossible to judge the degree of cement ring breakage in real time and determine the timing of termination of the extrusion operation. If the operation is terminated too early, the cement ring will not be completely broken, and the gap between the casing and the cement ring will be insufficient, which will not effectively reduce the pull-out resistance. If the operation is overdone, it will increase the operation time and energy consumption, and further aggravate the risk of casing damage.

[0069] Based on this, the present invention provides a rotary compaction cement crushing tool, such as... Figures 1 to 12 As shown, its structure is roughly the same as existing cement breaking tools, except that several top blocks 7 are inserted circumferentially along the main shaft 1 on the lower connector 3. Each top block 7 includes a rod-shaped portion 701 extending radially along the main shaft 1 and an arc-shaped portion 702 that can contact the inner wall of the sleeve. The arc-shaped portion 702 has a C-shaped cross-section and its opening faces the lower connector 3. To facilitate the installation of the top blocks 7, several slots 303 extending radially along the main shaft 1 are provided on the side wall of the lower connector 3. When installing the top blocks 7... The slide is inserted into the slot 303; a second spring 8 is also provided in the slot 303, with the two ends of the second spring 8 respectively located between the bottom of the slot 303 and the inner end of the rod-shaped part 701 of the top block 7. Under the action of the second spring 8, the top block 7 can slide elastically along the radial direction of the main shaft 1; the slot 303 and the throttling cavity 302 flow. When hydraulic oil enters the slot 303, under the action of hydraulic pressure, the top block 7 extends outward and is rubbed and locked on the inner wall of the sleeve by the arc-shaped part 702.

[0070] The end of the fluid channel 101 is flared along the flow direction; a rod 9 is provided in the pressure regulating channel 301. The rod 9 extends axially along the main shaft 1 and its bottom end is threaded into the top of the pressure regulating channel 301. The end of the rod 9 facing the fluid channel 101 is tapered and gradually expands along the flow direction of the fluid channel 101, and is inserted into the end of the fluid channel 101; to ensure the connection between the fluid channel 101 and the pressure regulating channel 301, a connecting groove 901 extends upward at the bottom end of the rod 9. The connecting groove 901 is connected to the pressure regulating channel 301. Several connecting holes 902 are circumferentially opened on the side wall of the rod 9. The connecting holes 902 connect the fluid channel 101 and the connecting groove 901.

[0071] When performing well abandonment operations, the target casing section is first cut into segments to make each segment independent, ensuring that the rotational resistance of each segment is not too great, so as to avoid affecting the subsequent triggering of the breakage completion signal. Then, the rotary crushing cement breaking tool is lowered from the top of the casing to the segment of the target casing section. Hydraulic oil is then injected into the fluid channel 101. Part of the hydraulic oil flows into the piston hole 102 and, under hydraulic action, pushes the piston 5 to slide outward. The piston 5 simultaneously pushes the moving roller 2, causing the moving roller 2 and the main shaft 1 to be eccentrically set. When the moving roller 2 moves, it simultaneously drives the straightening block 601 to move inward, and the first spring 602 is compressed and stored. Another part of the hydraulic oil flows into the throttling chamber 302. Part of it passes through the connecting hole 902, the connecting groove 901, and the pressure regulating channel 301 in sequence before flowing into the inner cavity of the casing. The other part flows into the slot 303. Under hydraulic action, the top block 7 extends outward and is locked to the inner wall of the casing by friction through the arc-shaped part 702. The second spring 8 extends.

[0072] When the moving roller 2 comes into contact with the inner wall of the casing, the drilling rig drives the main shaft 1 to rotate and move axially. When the main shaft 1 rotates, it drives the moving roller 2 to rotate eccentrically. Since the moving roller 2 is equipped with a radial bearing B203, the moving roller 2 "rolls" against the inner wall of the casing in a rolling contact manner, causing the casing to undergo elastic deformation, thereby destroying the cement ring at the circumferential position of the moving roller 2. When the main shaft 1 moves axially, it drives the moving roller 2 to move axially, destroying the cement ring at the axial position, until the cement ring at the segment of the target casing section is completely destroyed.

[0073] During the cement ring breaking process, because the top block 7 is frictionally locked against the inner wall of the casing, the lower connector 3 will not rotate with the main shaft 1. Under the threaded engagement between the main shaft 1 and the lower connector 3, the lower connector 3 approaches the main shaft 1, causing the tip of the insertion rod 9 to be inserted into the end of the fluid channel 101. While gradually reducing the flow area at the end of the fluid channel 101, the liquid pressure in the fluid channel 101 is increased, thereby increasing the total lateral thrust of the moving roller 2 and improving the breaking strength. When the cement ring at the segment of the target casing section is completely destroyed, the friction between the top block 7 and the inner wall of the casing... When locked, the segment of the target casing rotates synchronously with the main shaft 1. At this time, the depth of the insertion of the top of the insertion rod 9 into the end of the fluid channel 101 remains unchanged, and the liquid pressure in the fluid channel 101 tends to stabilize, indicating that the cement ring at the segment of the target casing has been completely destroyed. This makes it easier to determine the termination time of the extrusion operation, avoiding premature termination, incomplete crushing of the cement ring, insufficient gap between the casing and the cement ring, and failure to effectively reduce the pull-out resistance. It also avoids over-operation, which would increase the operation time and energy consumption, and further aggravate the risk of casing damage.

[0074] After the cement sheath at the segment of the target casing section is completely destroyed, the hydraulic pressure is canceled, and then the drill rig drives the spindle 1 to reverse. With the threaded engagement between the spindle 1 and the lower connector 3, the lower connector 3 moves away from the spindle 1 until it is reset, which facilitates the breaking of the cement sheath at the segment of the next target casing section.

[0075] Furthermore, to prevent the top block 7 from detaching from the lower connector 3, the inner end of the rod-shaped portion 701 of the top block 7 is designed as a stepped structure with a smaller outer diameter and a larger inner diameter, and a retaining ring 10 is fitted on the lower connector 3. The retaining ring 10 has several through holes along its circumference, through which the rod-shaped portion 701 of the top block 7 passes. The size of the through holes matches the size of the small section of the inner end of the rod-shaped portion 701 of the top block 7, so as to limit the position of the top block 7 sliding outward.

[0076] In one embodiment, in order to make the liquid pressure in the fluid channel 101 exhibit a stable, continuous, and linear adjustment characteristic as the flow cross section changes, and to avoid sudden pressure rises, falls, or local eddy current disturbances caused by abrupt changes in cross section, the cone angle at the end of the fluid channel 101 is set to be equal to the cone angle at the cone end of the insert 9.

[0077] Thus, when the main shaft 1 and the lower connector 3 undergo relative axial displacement, the tapered end of the insert rod 9 and the tapered surface at the end of the fluid channel 101 change the flow cross section in a fitted and equal taper manner, and the annular flow area between the two is uniformly and gradually changes along the axial direction.

[0078] This equal taper matching ensures a smooth transition between the contraction and expansion of the flow channel as the liquid flows through the mating area, effectively avoiding uneven local throttling effects, pressure fluctuations, and sudden changes in flow rate. This allows the lateral thrust acting on piston 5 to steadily increase or decrease as the operation progresses, thereby ensuring that the crushing action of the moving roller 2 on the sleeve and cement ring is continuous, balanced, and controllable, improving the crushing effect of the cement ring and the stability of the operation process.

[0079] In one embodiment, to prevent impurities inside the sleeve from affecting the threaded fit between the lower connector 3 and the main shaft 1, a protective sleeve 11 is fitted at the end of the main shaft 1 and outside the lower connector 3. The protective sleeve 11 is a cylindrical structure, and its top end is axially limited by a limiting boss 104 on the main shaft 1. The limiting boss 104 is located near the end of the main shaft 1 and is annular in shape. A sealed cavity is formed between the protective sleeve 11, the main shaft 1, and the lower connector 3. The threaded fit section of the main shaft 1 and the lower connector 3 is located within the sealed cavity. In this way, the protective sleeve 11 isolates the threaded fit section of the main shaft 1 and the lower connector 3 from the cavity inside the sleeve, preventing impurities inside the sleeve from affecting the threaded fit between the lower connector 3 and the main shaft 1.

[0080] Furthermore, a first annular platform 304 is provided on the lower connector 3; a second annular platform 1101 is provided on the inner peripheral wall of the bottom end of the protective sleeve 11. The second annular platform 1101 can form a stop engagement with the first annular platform 304 to limit the downward movement position of the lower connector 3.

[0081] In one embodiment, to facilitate the assembly of components and subsequent maintenance and replacement work, the protective sleeve 11 and the spindle 1 are configured to be detachably connected.

[0082] In a further embodiment, the protective sleeve 11 can be detachably attached to the end of the spindle 1 by fasteners such as screws.

[0083] Specifically, the screw is positioned near the top of the protective sleeve 11.

[0084] In other embodiments, the protective sleeve 11 can also be detachably connected to the spindle 1 via a pin.

[0085] In one embodiment, in order to improve the operational stability of the tool, expand the effective crushing range of the cement ring, and ensure that the circumferential force and extrusion of the casing are more balanced, multiple moving rollers 2 are set, and the multiple moving rollers 2 are arranged sequentially along the axial direction of the main shaft 1, and the eccentric action direction of each moving roller 2 is staggered with each other along the circumferential direction of the main shaft 1; adjacent moving rollers 2 can be axially limited by the limiting block B4.

[0086] In this way, the multiple axially arranged moving rollers 2 can simultaneously apply radial force to the casing, significantly increasing the length of the cement ring in the axial direction and improving the crushing coverage of a single operation. The circumferentially staggered eccentric structure allows the extrusion points of each moving roller 2 on the inner wall of the casing to be evenly distributed circumferentially, avoiding concentrated force in one direction that could cause large sway of the main shaft 1, thereby reducing the eccentric rotation amplitude of the main shaft 1 and improving the centering of the tool within the casing. At the same time, the circumferentially staggered multi-point extrusion can produce more uniform elastic deformation of the casing, more fully transmitting the force to the external cement ring, so that the cement ring can be subjected to continuous and balanced crushing action in both the circumferential and axial directions, effectively improving the integrity and uniformity of cement ring crushing, avoiding the situation where the local cemented surface is not effectively destroyed, and further reducing the pull-out resistance during casing retrieval.

[0087] As an example, the number of moving rollers 2 can be set to four.

[0088] In a further embodiment, to simplify the structure, when there are three or more movable rollers 2, the two outermost movable rollers 2 are configured to replace the upper roller and the lower roller.

[0089] This invention also provides a sleeve replacement construction process, which uses the above-mentioned rotary compactor cement crusher. The sleeve replacement construction process includes the following steps:

[0090] Segmented casing cutting: The target casing segment is cut into segments using a casing cutting tool;

[0091] Specifically, the casing cutting tool can be a hydraulic cutter or a mechanical cutter; depending on the set length range of the target casing and the retrieval capability, the long section of casing can be divided into several short sections to facilitate subsequent breaking and retrieval.

[0092] Tool Change: Remove the casing cutting tool, and then lower the rotary compactor cement breaker to the target casing section;

[0093] According to the casing specifications and the depth of the target casing section, a suitable rotary compactor cement breaker can be selected, and then the tool is connected to the bottom of the drilling rig and lowered to the target casing section.

[0094] Cement crushing: Indirectly crushes cement rings by rotating and compacting cement crushing tools;

[0095] Specifically, the rotary compactor continuously compresses the casing during rotation, causing periodic elastic deformation. This deformation transfers force to the external cement sheath. Because the cement sheath is brittle, it develops fatigue cracks under alternating stress and eventually breaks under the pressure, thus releasing it from its confinement over the casing. This process requires controlling the appropriate rotation speed and drilling pressure to efficiently break the cement sheath while avoiding damage to the casing or the tool.

[0096] Tool replacement: Remove the rotary compactor cement breaker, and then lower the retrieval tool to the target casing section;

[0097] Casing retrieval: The cut target casing sections are retrieved separately using retrieval tools.

[0098] Specifically, the salvage tool can be a dredging tube.

[0099] In a further embodiment, to ensure successful retrieval, the following steps are included before the retrieval of the casing:

[0100] Enlarging the sleeve coupling: Lower the enlarging tool to the sleeve coupling position and enlarge the sleeve coupling position accordingly.

[0101] Specifically, due to the large outer diameter of the casing coupling, in order to prevent it from being stuck by the small diameter of the wellbore during the retrieval process, a small-sized reamer can be lowered to specifically enlarge the casing coupling position, eliminate the shoulder obstruction, and ensure that the casing can be pulled out smoothly.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A rotary compactor for crushing cement, characterized in that, The main shaft (1) is capable of both rotation and axial movement. Two rollers are axially spaced on the main shaft (1) to maintain its centered position during operation. A movable roller (2) is also mounted on the main shaft (1) between the two rollers. A piston (5) and a stabilizer (6) are positioned opposite each other on the inner side of the movable roller (2) within the side wall of the main shaft (1). A fluid channel (101) is provided inside the main shaft (1). When liquid is injected into the main shaft (1) through the fluid channel (101), under hydraulic pressure, the piston (5) drives the movable roller (2) to move radially, deviating from the axis of the main shaft (1). After the hydraulic pressure disappears, the stabilizer (6) drives the piston (5) and the movable roller (2) to return to their original positions. The end of the main shaft (1)... The end is threaded with a lower connector (3). The lower connector (3) has a pressure regulating channel (301) that is connected to the fluid channel (101) and the internal cavity of the sleeve. Several top blocks (7) are inserted on the lower connector (3) along the circumference of the main shaft (1). The top blocks (7) can slide elastically along the radial direction of the main shaft (1) and can extend outward and be rubbed and locked on the inner wall of the sleeve under hydraulic action. The end of the fluid channel (101) is a flared structure along the flow direction. The pressure regulating channel (301) is provided with a rod (9). The end of the rod (9) facing the fluid channel (101) is a tapered structure and gradually expands along the flow direction of the fluid channel (101) and is inserted into the end of the fluid channel (101).

2. The rotary compactor cement crusher according to claim 1, characterized in that, The taper at the end of the fluid channel (101) is equal to the taper at the tapered end of the insert (9).

3. The rotary compactor cement crusher according to claim 1, characterized in that, A protective sleeve (11) is fitted at the end of the main spindle (1) and outside the lower connector (3). A sealed chamber is formed between the protective sleeve (11), the main spindle (1), and the lower connector (3). The threaded sections of the main spindle (1) and the lower connector (3) are located in the sealed chamber.

4. The rotary compactor cement crusher according to claim 3, characterized in that, The protective sleeve (11) and the spindle (1) can be detachably connected.

5. The rotary compactor cement crusher according to claim 4, characterized in that, The protective sleeve (11) is detachably connected to the end of the spindle (1) by screws.

6. The rotary compactor cement crusher according to claim 1, characterized in that, There are multiple moving rollers (2), which are arranged along the axial direction, and the eccentric directions of different moving rollers (2) are offset along the main shaft (1) circumferentially.

7. The rotary compactor cement crusher according to claim 6, characterized in that, There are three or more movable rollers (2), and the two outermost movable rollers (2) replace two rollers.

8. The rotary compactor cement crusher according to claim 6, characterized in that, There are four moving rollers (2).

9. A method for replacing sleeves during construction, characterized in that, Using the rotary compactor cement crusher as described in claim 1, the replacement process includes the following steps: Segmented casing cutting: The casing cutting tool is lowered to the target casing segment, and the target casing segment is cut into segments using the casing cutting tool; Tool Change: Remove the casing cutting tool, and then lower the rotary compactor cement breaker to the target casing section; Cement crushing: Indirectly crushes cement rings by rotating and compacting cement crushing tools; Tool replacement: Remove the rotary compactor cement breaker, and then lower the retrieval tool to the target casing section; Casing retrieval: The cut target casing sections are retrieved separately using retrieval tools.

10. The sleeve replacement construction process according to claim 9, characterized in that, Before the casing retrieval step, the following steps are also included: Enlarging the sleeve coupling: Lower the enlarging tool to the sleeve coupling position and enlarge the sleeve coupling position accordingly.

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