Milling anti-rotation type composite material packer

Abstract

The utility model belongs to the technical field of oil field downhole tools, and particularly relates to a casing milling anti-rotation type composite material packer which comprises a center flow channel formed by sequentially connecting an upper connector, an upper center pipe, a lower center pipe and a lower connector, a setting mechanism, a sealing locking mechanism and an anti-rotation structure. According to the setting mechanism, a setting piston is hydraulically driven to compress a rubber barrel assembly to achieve sealing, and a locking claw is driven to expand outwards and be anchored to the inner wall of the sleeve. The anti-rotation structure is arranged between the center pipe and the outer sleeve assembly and comprises a flat key and a plurality of anti-rotation screws, the flat key is used for limiting circumferential relative rotation and allowing axial relative sliding, and the anti-rotation screws are screwed into the outer sleeve assembly in the radial direction and matched with the center pipe to form auxiliary anti-rotation points. By means of a composite anti-rotation system formed by the flat key and the anti-rotation screw, torque can be effectively transmitted during casing milling, the packer is prevented from rotating along with the milling shoe, casing milling efficiency is remarkably improved, abrasion of the milling shoe and the casing pipe is reduced, and the technical problem that an existing casing milling packer is prone to rotating along with the milling shoe in the removing process is solved.

Description

Technical Field

[0001] This utility model relates to the field of oilfield downhole tool technology, specifically to a milling anti-rotation composite material packer. Background Technology

[0002] The composite packer is a common downhole tool widely used in oilfield operations such as fracturing, water injection, and oil production. It is made of composite materials (such as resin or fiber-reinforced materials), facilitating subsequent milling operations, and possesses excellent resistance to high temperatures and pressures.

[0003] The prior art (CN205445541U) discloses a drillable packer for integrated fracturing and production construction of deep gas wells. This packer uses drillable materials such as cast iron to manufacture components such as the working cylinder and slips, allowing it to be milled by a milling tool when needed, thus enabling tubing recovery and solving the problems of production commencement without tubing replacement after fracturing and tool recovery.

[0004] However, in practical milling operations, a significant drawback affecting the efficiency of this type of drillable packer has been observed. During milling, as the milling tool rotates and contacts the packer body for grinding, components anchored to the sleeve wall (such as slips and locking mechanisms) are prone to circumferentially "following" or "idling" along with the milling shoe due to friction. This "following" phenomenon results in a large amount of milling torque being consumed in overcoming this useless rotational friction, rather than being effectively used to cut the packer body material. This significantly reduces the efficiency of milling operations, while also exacerbating unnecessary wear on the milling shoe and the inner wall of the sleeve, increasing operating costs and risks. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a composite material packer for milling and anti-rotation, which can effectively prevent rotation and ensure milling efficiency.

[0006] The technical solution adopted in this utility model is as follows:

[0007] Includes a central tube, which consists of an upper connector, an upper central tube, a lower central tube, and a lower connector, which are connected in sequence to form a central flow channel;

[0008] The setting mechanism includes a hydraulic chamber surrounded by an upper cylinder liner and a lower cylinder liner, a setting piston disposed in the hydraulic chamber, and a shear pin for controlling the initial position of the setting piston.

[0009] A rubber sleeve assembly fitted outside the central tube, the rubber sleeve assembly comprising a long rubber sleeve, a short rubber sleeve, and a spacer ring located between them.

[0010] A locking mechanism, comprising a locking sleeve and a locking claw, wherein the setting piston moves under hydraulic drive to compress the rubber sleeve assembly to cause it to expand radially and seal, and drives the locking claw to extend outward to anchor against the inner wall of the sleeve;

[0011] An anti-rotation structure is provided, comprising a flat key and at least one anti-rotation screw; the flat key is disposed between the upper center tube and the locking sleeve; the anti-rotation screw is screwed in radially, and the end of the anti-rotation screw engages with the center tube.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0013] The above structure ensures that the components anchored to the sleeve do not rotate with the milling shoe during milling operations, thus allowing the milling torque to be fully applied to the cutting tool body. This significantly improves milling efficiency, reduces wear on the milling shoe and sleeve, and solves the technical problem of existing milling packers easily rotating during removal.

[0014] In a preferred embodiment of the present invention, the sealing mechanism further includes a locking pin seat, and the shear pin is installed in the locking pin seat; the locking mechanism further includes a release sleeve and a release pin, the release sleeve being limited by the release pin, and releasing the constraint on the locking claw when unsealing.

[0015] Beneficial effects: The combination of shear pins and locking pin seats enables precise control of the setting pressure, ensuring reliable triggering of the setting action; it provides an alternative recovery method for the packer in situations where milling is not required, increasing the flexibility of tool application.

[0016] As a preferred embodiment of this utility model, it also includes a backwashing mechanism, which includes a backwashing valve that is closed when water is injected to prevent the injected fluid from flowing back; when well washing or reverse flushing is required, it is opened under the action of pressure difference to allow the well fluid to return from the bottom to the interior.

[0017] Beneficial effects: The above structure enables the packer to achieve controllable unidirectional reverse circulation well washing even after setting. This function can effectively remove sand, debris, and other impurities from the wellbore above the packer and the near-wellbore area, preventing sand buildup and pipe jamming.

[0018] In a preferred embodiment of the present invention, the rubber tube assembly further includes a rubber tube liner sleeved outside the central tube, and the long rubber tube and the short rubber tube are sleeved outside the rubber tube liner; a copper protective cup is also provided at the lower end of the rubber tube assembly.

[0019] Beneficial effects: The rubber sleeve liner provides internal rigid support for the rubber sleeve assembly, ensuring that the axial load is evenly transmitted during setting, promoting uniform radial expansion of the rubber sleeve, and forming a more reliable seal. The copper cup is located at the lower end of the rubber sleeve assembly and can act as a sacrificial protective layer during milling or well washing operations, preferentially absorbing wear from the milling shoe or erosion from the fluid.

[0020] In a preferred embodiment of the present invention, a balance piston is also included, which is disposed below the upper connector.

[0021] Beneficial effects: The setting of the balancing piston can dynamically balance the fluid pressure difference between the upper and lower parts of the packer sleeve, reducing the pressure differential load that the sleeve bears over a long period of time.

[0022] In a preferred embodiment of this utility model, a protective seat is provided between the upper connector and the upper central tube.

[0023] Beneficial effects: The protective seat can provide mechanical protection and axial positioning for internal precision mechanisms such as the balance piston and backwash valve. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of an embodiment of the milling anti-rotation composite material packer of this utility model;

[0025] Figure 2 yes Figure 1 First enlarged view of the area;

[0026] Figure 3 yes Figure 1 Second enlarged view of the area;

[0027] Figure 4 yes Figure 1 The third enlarged view;

[0028] Figure 5 yes Figure 1 The fourth enlarged view.

[0029] The attached reference numerals include: 1. Upper connector; 2. Protective seat; 3. Unsealing pin; 4. Balance piston; 5. First O-ring; 6. Second O-ring; 7. Piston retaining ring; 8. Upper central tube; 9. Third O-ring; 10. Backwash valve; 11. Fourth O-ring; 12. Backwash valve sleeve; 13. Well washing rubber pad; 14. Backwash seat; 15. Rubber sleeve liner; 16. Long rubber sleeve; 17. Upper spacer ring; 18. Short rubber sleeve; 19. Lower spacer ring; 20. Copper protective cup; 21. Adjusting ring; 22. Locking sleeve; 23. Locking claw; 24. Release sleeve; 25. Locking pin; 26. Locking sleeve rear ring; 27. Sealing piston; 28. Upper cylinder liner; 29. ​​Lower central tube; 30. Connector; 31. Fifth O-ring; 32. Sixth O-ring; 33. Lower cylinder liner; 34. Lower connector; 35. Locking pin seat; 36. Shear pin; 37. Flat key; 38. First anti-rotation screw; 39. Second anti-rotation screw. Detailed Implementation

[0030] Typical embodiments embodying the features and advantages of this utility model will be specifically described in the following description. It should be understood that this utility model can have various variations in different embodiments, all of which do not depart from the scope of this utility model, and the descriptions and illustrations therein are for illustrative purposes only and not intended to limit this utility model.

[0031] In the description of this application, the terms "first", "second", etc. are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the structure referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] See Figures 1 to 5 As shown, this embodiment discloses a milled anti-rotation composite material packer, which includes the following parts:

[0033] Force transmission connection structure: upper connector 1. Upper connector 1 is a load-bearing component that connects to the upper oil pipe or tubing string. At the same time, it forms an internal flow channel with the upper central pipe 8. It is the main connection interface between the packer and the upper tubing string and bears axial tensile and compressive loads as well as transmits torque.

[0034] The upper central tube 8, the upper main load-bearing tube of the packer, is connected to the upper connector 1 and the lower central tube 29, and has an open main flow channel inside. All components such as seals, rubber sleeves, and pistons are mounted on it as the base, transmitting axial loads and well-washing fluid / injection flow rate vertically.

[0035] The lower center tube 29 is a lower extension of the center tube, which receives the upper center tube 8 and connects to the lower connector 34 or the connector 30, with a main flow channel inside. Its outer surface may also be machined with sealing grooves and keyways to provide an installation reference for parts such as the seated piston 27 and cylinder liners.

[0036] The lower connector 34 is the final connection between the packer and the lower tubing or tailpipe. The lower end of the lower connector 34 has a standard tubing thread or a special connector to enable series connection with other downhole tools; the interior has a sealing surface and a flow channel transition area to ensure unobstructed flow inside and outside the tubing after unsealing.

[0037] Connector 30 is installed below the lower center tube 29 and is used to connect the lower tubing, tailpipe, or other downhole tools. It also allows for transitions between different diameters or thread types, facilitating on-site assembly of tubing strings.

[0038] Sealing institution:

[0039] The upper cylinder liner 28, in conjunction with the setting piston 27, forms the upper cylindrical part of the hydraulic cavity, which serves as a pressure vessel and provides a sliding guide surface for the piston. It also achieves isolation between the inside and outside of the cavity through the sealing ring, ensuring the pressure utilization efficiency during the setting process.

[0040] The lower cylinder liner 33 is the lower closed cylinder of the hydraulic chamber. On the one hand, it provides a lower end guide and sealing surface for the seated piston, and on the other hand, it works with the upper cylinder liner 28 to limit the effective stroke of the piston. It also serves as the outer shell of the structure, bearing the external sleeve pressure and internal hydraulic pressure.

[0041] The setting piston 27 is the hydraulic setting actuator of the packer. When a specified pressure is applied inside the wellbore, fluid enters the piston chamber through the small hole in the central tube, pushing the setting piston 27 downward and transmitting the axial load to the rubber sleeve and locking claw 23, thereby realizing the compression and expansion of the rubber sleeve and the outward anchoring of the locking claw 23.

[0042] The locking pin seat 35 is a carrier specifically designed for mounting the shear pin 36, located between the lower cylinder liner 33 and the lower connector 34. By machining blind holes or steps on it, reliable force distribution and controllable shearing values ​​for the shear pin 36 are ensured, and disassembly and replacement are facilitated. When used in conjunction with the release sleeve 24, the setting piston 27, etc., it determines the sequence of actions.

[0043] The shear pin 36 is used to restrict the movement of critical components (such as the setting piston, release sleeve 24, etc.) before the design pressure is reached. It shears off upon reaching the design hydraulic pressure or lifting force, releasing the restrained component and allowing it to operate according to a predetermined program. It is a core small component of the packer's "program control".

[0044] Glue Sleeve Assembly:

[0045] The rubber sleeve liner 15 is a steel bushing fitted inside the rubber sleeve. It mainly provides rigid support for the long rubber sleeve 16 and the short rubber sleeve 18 to prevent the rubber sleeve from sinking during the setting and compression. It also evenly transfers the load on the central tube to the rubber sleeve, so that it is axially compressed and radially expanded to form a reliable seal.

[0046] The long rubber sleeve 16 is one of the main sealing elements of the packer. Under the action of axial setting load, it is compressed and expands radially, forming a large contact area with the inner wall of the sleeve to achieve the main packing. At the same time, it cooperates with the upper spacer ring 17 and the lower spacer ring 19 to withstand long-term differential pressure.

[0047] The upper spacer ring 17, the metal partition between the long rubber sleeve 16 and the short rubber sleeve 18, and the support ring are used to limit the working length of the rubber sleeve, prevent the rubber from being "extruded" axially during compression, and simultaneously distribute the upper load in segments, improving the stress state of the rubber sleeve and enhancing its extrusion resistance. It also includes the short rubber sleeve 18, an auxiliary sealing rubber sleeve arranged in series with the long rubber sleeve 16, used to enhance the overall sealing length and redundant sealing capacity. Different ratios can be adapted to different sleeve sizes or differential pressure levels, and after setting, it shares the sealing task with the long rubber sleeve 16. This is the main sealing mechanism of the tool, operating on a compression basis, compressing under axial setting load.

[0048] The lower spacer ring 19, located at the lower end of the rubber sleeve assembly, provides support and limit for the short rubber sleeve 18, and evenly transmits the axial load generated by the lower piston to the rubber sleeve assembly, preventing the rubber sleeve from being squeezed downwards or damaging other structures.

[0049] The copper protective cup 20 is a copper or copper alloy protective component located below the rubber sleeve or above the anchoring component. It acts as a "buffer pad" during milling or well cleaning to prevent the steel teeth and milling shoes from directly impacting the rubber sleeve or key conical surface. It can be replaced separately after wear to protect the main structure from damage.

[0050] Locking mechanism:

[0051] The locking claw 23 is a toothed anchoring component that engages with the inner wall of the sleeve. The outer surface is arranged with carbide teeth or machined teeth, and the inner surface is matched with a conical surface. During the piston push, it expands radially outward, bites into the sleeve to complete the anchoring, and transmits axial tension and partial torque.

[0052] Lock sleeve 22 is the main locking sleeve of the anchoring system. After the setting is completed, it cooperates with lock claw 23 and lock sleeve rear ring 26 under axial load to keep lock claw 23 open and biting the inner wall of the sleeve, preventing the rubber sleeve from springing back and the packer from sliding up. It is the key structure to achieve self-locking retention.

[0053] Locking pins 25 (using shear pins) pass through the rear ring 26 and the locking sleeve 22 in sequence for fixation, and are used to precisely control the starting force of the anchoring or unlocking action; different quantities and specifications can adjust the design load to ensure reliable sealing and avoid malfunctions.

[0054] The adjusting ring 21 is used to adjust the relative position between the locking sleeve 22, the locking claw 23, and the rubber sleeve / piston, precisely controlling the setting stroke and locking preload. By changing the thickness of the adjusting ring 21, different sleeve inner diameters or rubber sleeve ratios can be matched, facilitating serialized design.

[0055] The rear ring 26 of the locking sleeve is a limiting ring located at the lower end or rear side of the locking sleeve 22. It is used to bear the reaction force of the locking claw 23 and limit its axial displacement; together with the locking sleeve 22, it forms a closed cavity to "enclose" the locking claw 23 and prevent it from spreading out or getting stuck during operation.

[0056] The release pin 3 and release sleeve 24 are sleeve structures used to control the timing of the unlocking of the locking claw 23. In cooperation with the shear pin 36, adjusting ring 21, etc., they are driven to move by hydraulic pressure or lifting force in the unsealing condition, releasing the constraint on the locking sleeve 22 / locking claw 23, so that the locking claw 23 can be retracted, thereby realizing the unsealing of the packer or the unloading before milling.

[0057] The balancing piston 4 is a piston component used to balance the fluid pressure inside and outside the packer. On the one hand, it forms a chamber with the outer cylinder through the seal, reducing the pressure difference on both sides of the packer and preventing fatigue damage to the packer due to long-term high differential pressure; on the other hand, it automatically compensates for volume changes when well washing / water injection conditions change, improving sealing stability.

[0058] Anti-washing agency:

[0059] The backwash seat 14, the valve seat component of the backwash valve 10 assembly, provides a sealing surface for the valve core's conical or planar contact. It withstands pressure differentials and guides the flow path to the designated channel, making it a key component for achieving unidirectional backflow and pressure differential sealing.

[0060] Backwash valve 10 is a valve that enables unidirectional backwashing. It is closed during normal water injection to prevent backflow of the injected fluid; when well washing or reverse flushing is required, it is opened under pressure differential to allow well fluid to return from the bottom into the pipe, thereby carrying away impurities and enabling well washing.

[0061] The backwash valve sleeve 12 serves as the mounting housing and guide sleeve for the backwash valve 10. It provides axial guidance and a sealing chamber for the valve core, and through its connection with the central tube and upper cylinder sleeve 28, it forms a local pressure chamber, providing a closed space for the backwash and setting fluid circuit.

[0062] The protective seat 2, installed below the upper connector 1, provides axial positioning and mechanical protection for the internal balance piston 4, backwashing mechanism, etc., preventing impact and wear during the running-in or running-out of the tubing or well washing process. It also serves as a local seal and flow channel transition support.

[0063] The well-washing rubber pad 13 is placed near the backwash valve 10 assembly to absorb the impact during valve opening / closing and enhance the seal. Its elastic deformation can compensate for the mating clearance, improve the erosion resistance during well washing, and prevent damage to metal parts caused by hard collisions.

[0064] Anti-transfer agency:

[0065] The flat key 37, installed between the upper center tube 8 and the outer sleeve or locking sleeve 22, achieves an anti-rotation connection between the two parts by cooperating with the keyway, allowing a certain amount of axial sliding while transmitting torque. This ensures torque transmission during milling and lifting without interfering with the setting seal stroke.

[0066] The first anti-rotation screw 38 (M12) is one of the large-diameter anti-rotation screws located on the outer cylinder and internal key components. It improves the torsional rigidity between the parts by radial tightening or through-locking, preventing relative rotation during milling, backwashing, or high-torque operations.

[0067] The second anti-rotation screw 39 (M10) is a small-sized anti-rotation fastener used in conjunction with the M10 and M12 anti-rotation screws. It is typically used in space-constrained areas or where strength requirements are slightly lower. It also serves to prevent rotation, positioning, and loosening, while being easy to disassemble and replace on-site, reducing the number of anti-rotation structure sizes.

[0068] The first O-ring 5 (the upper set) is installed between the mating surfaces of the upper connector 1, protective seat 2, and balance piston 4 to achieve static or micro-motion sealing between these parts, preventing the well-washing fluid and injection water from flowing across the upper flow channel. This part is a general-purpose seal, and its size can be adjusted according to the design.

[0069] Piston retaining rings prevent the piston from moving excessively under hydraulic pressure, which could damage the piston sleeve or impact other parts. They also lock the piston, seals, and other parts in the cylinder liner, facilitating assembly and maintenance.

[0070] The second O-ring 6 is installed inside the balance piston 4 and is responsible for sealing the center tube and the outer shell, ensuring that the liquid can only flow through the designed flow channel and valve hole, and will not leak from the gap.

[0071] The third O-ring 9 and the fourth O-ring 11 (for sealing the backwash valve 10) are used to seal the backwash valve 10 with the valve sleeve and valve seat, ensuring that there is no leakage when the valve is closed and that the flow is controlled only through the valve port when it is open, thereby improving the controllability and sealing reliability of the backwash process.

[0072] The fifth O-ring 31 and the sixth O-ring 32 (located in the lower middle part of the packer) are respectively arranged in the setting piston between the lower cylinder liner 33 and the lower central tube 29, and between the lower cylinder liner 33 and the lower connector 34. They are responsible for sealing the flow channel in the lower middle part, preventing the injected water from flowing into the non-designed area along the gap, and ensuring the sealing effect and the reliability of the hydraulic setting.

[0073] The workflow and principle of this embodiment are as follows:

[0074] When the tool is lowered, the upper connector 1 is threaded to the upper tubing string, and the lower connector 34 is connected to the lower tubing string or test tool. The fluid in the well forms a through flow channel through the upper connector 1, the upper central tube 8, the lower central tube 29, and the lower connector 34. The setting piston 27 is confined within the hydraulic cylinder cavity formed by the upper cylinder liner 28 and the lower cylinder liner 33 by the shear pin 36 and the locking pin seat 35. The rubber sleeve assembly consists of a long rubber sleeve 16, a short rubber sleeve 18, an upper spacer ring 17, a lower spacer ring 19, and a rubber sleeve liner 15, and is in an uncompressed state. The locking sleeve 22 and the locking claw 23 are in a contracted position under the constraint of the adjusting ring 21 and the locking sleeve rear ring 26, and have not yet bitten into the inner wall of the casing. The packer can be freely raised and lowered with the tubing string and allows normal circulation, well washing, or backwashing. The backwash valve 10, the backwash valve sleeve 12, and the well washing rubber pad 13 ensure that a one-way backwashing function can be achieved when needed.

[0075] During setting, hydraulic pressure is applied to the packer from within the tubing string. The liquid enters the hydraulic chamber formed by the upper cylinder liner 28 and the lower cylinder liner 33 through the radial hole on the central tube. When the pressure inside the chamber rises to the design value, the shear pin 36 shears off, and the setting piston 27 moves axially downward under the hydraulic pressure. Its displacement is transmitted sequentially through the lower spacer ring 19, the rubber sleeve liner 15, the long rubber sleeve 16, and the short rubber sleeve 18. This causes the rubber sleeve assembly to undergo axial compression and radial expansion under the constraint of the upper and lower spacers and the copper protective cup 20, forming a reliable seal by tightly adhering to the inner wall of the casing. At the same time, the setting piston 27 drives the locking sleeve 22 to slide relative to the locking claw 23 along the inner conical surface, forcing the locking claw 23 to open outward. The slip teeth bite into the inner wall of the casing to complete the anchoring. The rear ring 26 of the locking sleeve provides reverse limiting for the locking sleeve 22, thereby realizing the bidirectional load-bearing of the packer. When unsealing, the locking claw 23 can be slowly disengaged from the sleeve and rubber sleeve by hydraulic or mechanical mechanisms such as the unsealing pin 3 and the release sleeve 24 according to a predetermined procedure, so that the packer returns to the unsealed state.

[0076] The innovation of this invention lies in the design of a composite anti-rotation structure to ensure that the packer can still effectively transmit torque under milling conditions, avoiding the problems of slip and cone rotation with the milling shoe in existing milling packers. Specifically, a flat key 37 and a matching keyway are provided between the central tube and the outer assembly (including the locking sleeve 22, the lower cylinder liner 33, and the outer cylinder structure connected thereto). This allows the outer assembly to slide relative to the central tube in the axial direction to complete the setting and unsetting strokes, but it is rigidly limited in the circumferential direction by the flat key 37, thereby reliably transmitting the torque borne by the central tube to the locking mechanism. To further enhance anti-rotation capability, multiple anti-rotation screws M12 and M10 are arranged at key connection points. These anti-rotation screws are radially screwed into pre-drilled holes in the outer sleeve components such as the locking seat 35, lower cylinder liner 33, and connector 30. Their ends mate with the central tube or corresponding grooves to form multiple discrete anti-rotation points, which together with the flat key 37 constitute a composite anti-rotation system of "key connection + multi-point anti-rotation screws".

[0077] In milling operations, the milling shoe progressively cuts the upper connector 1 and other millable parts such as the outer cylinder, locking sleeve 22, locking claw 23, and rubber sleeve liner 15 from top to bottom. The flat key 37 and anti-rotation screw used in this invention ensure that the milled parts always maintain a reliable torque transmission relationship with the central tube, preventing them from rotating with the milling shoe and concentrating the milling energy on the tool body. At the same time, the composite material and locally fragile metal structures are broken into small particles during the milling process and carried out of the wellbore by the circulating fluid, thereby significantly improving milling efficiency, reducing milling shoe wear, and ensuring safe and controllable removal of the packer under high-torque milling conditions. Through the above structure and working process, this invention, while maintaining the conventional hydraulic packer's setting, unsealing, and well-washing functions, realizes a composite material packer with high reliability and anti-rotation capability, particularly suitable for milling operations.

[0078] The functions of this device are as follows:

[0079] The invention features a composite anti-rotation component consisting of a flat key 37 and multiple anti-rotation screws between the central tube and the outer sleeve assembly. This component restricts the circumferential rotation of the outer sleeve while allowing it to slide axially relative to the central tube. This ensures reliable torque transmission from the tube column to the central tube and then to the locking mechanism, effectively preventing the problem of parts such as slips and cones spinning freely with the milling shoe during milling operations.

[0080] The hydraulic setting function uses a setting piston controlled by shear pin 36 to form a hydraulic chamber with the upper and lower cylinder liners. After the shear pin 36 is cut by pressure inside the pipe, the setting piston is driven to move downward, compressing the long and short rubber sleeves in sequence and pushing the locking sleeve 22 and locking claw 23 outward, realizing the hydraulic setting function of rubber sleeve sealing and slip anchoring, ensuring that the packer has a stable bidirectional pressure bearing capacity after setting.

[0081] The invention features a milling-capable structure, employing composite materials and free-milling metal structures in the rubber sleeve assembly, some outer sleeves, and anchoring components. This allows the tool to be cut into small fragments from top to bottom by the milling shoe when no longer in use, which are then carried out of the wellbore by the circulating fluid. Combined with the torque transmission function of the anti-rotation component, this improves the milling efficiency and reduces the wear of the milling shoe and casing.

[0082] The well-washing and unsealing design, through the setting of backwash valve 10, backwash valve sleeve 12, well-washing rubber pad 13 and protective seat 2, unsealing pin 3 and other components, forms a controllable flow channel and unsealing mechanism: during construction, it can realize forward and reverse washing to remove sand and debris in the near-well zone, and when the pressure in the pipe or the lifting load reaches the set value, it can cut off the pin, release the release sleeve 24 and locking claw 23, so that the rubber sleeve is restored and the slip is unlocked, thereby completing the reliable unsealing of the packer and creating conditions for the next operation or milling.

[0083] The composite material packer structure of this invention comprises a long packer 16, a short packer 18, a packer liner 15, an upper spacer ring 17, and a lower spacer ring 19. The packer is made of composite material or elastomer, while the liner and spacer ring are metal parts. During setting, the liner and spacer ring bear the axial force and constrain the deformation of the packer, providing a larger sealing contact area and elastic preload. When milling is required, the composite material packer and part of the outer metal can be quickly milled away. In conjunction with the anti-rotation structure, it balances packing performance and subsequent removability, making up for the shortcomings of traditional packers that make it difficult to balance packing reliability and easy removal.

[0084] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A milled composite material packer for preventing rollover, characterized in that, include: The central tube is composed of an upper connector, an upper central tube, a lower central tube, and a lower connector, which are connected in sequence to form a central flow channel; The setting mechanism includes a hydraulic chamber surrounded by an upper cylinder liner and a lower cylinder liner, a setting piston disposed in the hydraulic chamber, and a shear pin for controlling the initial position of the setting piston. A rubber sleeve assembly fitted outside the central tube, the rubber sleeve assembly comprising a long rubber sleeve, a short rubber sleeve, and a spacer ring located between them. A locking mechanism, comprising a locking sleeve and a locking claw, wherein the setting piston moves under hydraulic drive to compress the rubber sleeve assembly to cause it to expand radially and seal, and drives the locking claw to extend outward to anchor against the inner wall of the sleeve; An anti-rotation structure is provided, comprising a flat key and at least one anti-rotation screw. The flat key is disposed between the upper central tube and the locking sleeve. The anti-rotation screw is screwed in radially, and the end of the anti-rotation screw engages with the central tube.

2. The milled anti-rotation composite material packer according to claim 1, characterized in that: The sealing mechanism further includes a locking pin seat, and the shear pin is installed in the locking pin seat; the locking mechanism further includes a release sleeve and a release pin, the release sleeve is limited by the release pin, and the constraint on the locking claw is released when the seal is released.

3. The milled anti-rotation composite material packer according to claim 1, characterized in that: It also includes a backwashing mechanism, which includes a backwashing valve that is closed during water injection to prevent backflow of the injected fluid; when well washing or reverse flushing is required, it is opened under the action of pressure difference to allow the well fluid to return from the bottom to the interior.

4. The milled anti-rotation composite material packer according to claim 1, characterized in that: The rubber tube assembly also includes a rubber tube liner sleeved outside the central tube, and the long rubber tube and the short rubber tube are sleeved outside the rubber tube liner; a copper protective cup is also provided at the lower end of the rubber tube assembly.

5. The milled anti-rotation composite material packer according to claim 1, characterized in that: It also includes a balance piston, which is disposed below the upper connector.

6. The milled anti-rotation composite material packer according to claim 1, characterized in that: A protective seat is provided between the upper connector and the upper central tube.

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