Hydraulic cutter and retainer integrated tool for oil and gas well abandoned well operation

Abstract

The invention belongs to the technical field of oil and gas well discarding operation, and particularly relates to a hydraulic cutter and retainer integrated tool for oil and gas well discarding operation. The cement retaining device comprises a setting device and a retaining device and is used for blocking a target well section and completing cement squeezing and injecting operation; the snapping type sealing device is connected with the hydraulic cutting knife system and the retainer, and the snapping type sealing device is triggered by a lifting tool to plug the fluid channel so as to separate the upper cabin body and the lower cabin body after cement squeezing and injecting are completed; wherein the hydraulic cutting knife system is kept closed due to the fact that internal pressure does not reach an opening threshold value during cement squeezing and injecting operation, a piston is driven by high-pressure liquid to unfold a cutting knife to cut a casing pipe after the cement squeezing and injecting operation is completed, and the hydraulic cutting knife system is reset through a spring after cutting is completed. The breaking type sealing device, the hydraulic cutting knife system and the cement bearing device are integrally arranged, so that the seamless and streamline process of single cutting and well cementation of the casing pipe is realized, the construction procedures are reduced, and the construction efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas well abandonment operations, and particularly relates to an integrated tool of a hydraulic cutter and a retainer for oil and gas well abandonment operations. Background Art

[0002] With the gradual increase in the development years of oil and gas fields in China, more and more oil and gas wells put into production in the early stage have entered the low-production period and do not have the economic value for continued exploitation. The abandonment operations of such oil and gas wells have been gradually put on the agenda; the abandonment operations of oil and gas wells require plugging operations on the abandoned oil and gas wells to ensure safety and environmental protection; the cutting and recovery of casing are also an essential task in the abandonment operations of oil and gas wells.

[0003] A hydraulic cutter is a tool widely used in oil well abandonment operations, mainly used for cutting the downhole casing. The working principle of a traditional hydraulic cutter: When cutting the casing, high-pressure fluid is transmitted to the downhole through the drill string. After the high-pressure fluid enters the cutter tool, it pushes the cutter into contact with the casing and starts the cutting operation. After cutting is completed, the operator stops the supply of high-pressure fluid, and the piston of the cutter tool returns to its original position under the action of a spring or other mechanisms. At this time, the cutter tool is ready for the next cutting operation. A cement retainer is mainly used for temporarily or permanently plugging oil, gas, and water layers or for secondary cementing. The cement slurry is squeezed into the well section to be sealed in the annulus or into the fractures and pores of the formation through the retainer to achieve the purpose of plugging and leak repair. Its principle is that after the cement retainer is connected to a hydraulic setting tool, it is lowered to the predetermined position through the tubing. The cement retainer is set by applying pressure inside the tubing, and the setting tool is released. The hydraulic setting tool is inserted into the retainer again, and the valve body is opened to start the cement squeezing operation.

[0004] Since the existing hydraulic cutter and cement retainer are both independent components, the cement retaining step and the casing cutting and recovery step in traditional oil and gas well abandonment operations are carried out separately and independently. There are many construction procedures. First, the cement retainer is lowered into the well for cement squeezing operations. After the operation is completed, the recovery tool is lifted; then the hydraulic cutter is lowered into the well for casing cutting operations. After cutting is completed, the recovery tool is lifted to complete the entire well abandonment operation. Summary of the Invention

[0005] In order to solve or improve at least one problem existing in the prior art, the purpose of the present invention is to provide an integrated tool of a hydraulic cutter and a retainer for oil and gas well abandonment operations, which can reduce construction procedures and thus improve construction efficiency.

[0006] To solve the above problems, the present invention provides an integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, comprising: a hydraulic cutter system for cutting the casing, which is internally provided with a hydraulically driven piston, a spring and a deployable and retractable cutter, and a fluid passage is provided in the hydraulic cutter system; a cement retaining device comprising a packer and a retainer for plugging the target well section and completing the operation of squeezing cement; a pull - off sealing device connecting the hydraulic cutter system and the retainer, which triggers the pull - off sealing device to block the fluid passage to separate the upper and lower compartments by lifting the tool after the squeezing of cement is completed; wherein, the hydraulic cutter system remains closed during the cement squeezing operation because the internal pressure does not reach the opening threshold, and after the cement squeezing operation is completed, the piston is driven by high - pressure liquid to deploy the cutter to cut the casing, and after the cutting is completed, the cutter is retracted by the spring reset.

[0007] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the pressure threshold required for the cutter to open is 45 Mpa to 50 Mpa.

[0008] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the upper and lower surfaces of the piston are different.

[0009] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the area ratio of the upper and lower surfaces of the piston is 1.2:1 to 1.5:1.

[0010] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the pull - off sealing device comprises a rubber blocking plug and a tension - triggered metal rod. The rubber blocking plug is arranged in the fluid passage of the hydraulic cutter system. One end of the tension - triggered metal rod is connected to the rubber blocking plug, and the other end of the tension - triggered metal rod passes through the packer and is connected to the retainer. When the tool is lifted to a predetermined tension, the tension - triggered metal rod and the rubber blocking plug are pulled apart and separated, and the rubber blocking plug blocks the fluid passage to isolate the upper and lower compartments.

[0011] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the fluid passage of the hydraulic cutter system comprises an inverted conical pipe, and the rubber blocking plug blocks the fluid passage through cooperation with the conical pipe to isolate the upper and lower compartments.

[0012] As a further improvement of the above - mentioned integrated tool of a hydraulic cutter and a retainer for abandonment operations of oil and gas wells, the separation tension between the tension - triggered metal rod and the rubber blocking plug is set by screw pre - tightening force.

[0013] As a further improvement of the above-mentioned integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations, the setting packer includes a core, a reed, and a spring block. A fluid passage is provided inside the core, and an annular groove is provided on the outer wall of the core. The annular groove is used to install the reed and the spring block. One end of the core is connected to the hydraulic cutter system, and the other end of the core is connected to the retainer.

[0014] As a further improvement of the above-mentioned integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations, the retainer includes a dynamic roller, and a clamp, a static roller, and a retainer pipe wall sleeved outside the dynamic roller. The clamp and the retainer pipe wall are respectively provided on both sides of the static roller, and the retainer pipe wall is located between the static roller and the clamp.

[0015] As a further improvement of the above-mentioned integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations, the hydraulic cutter system includes a cutter system body, a hydraulically driven piston, a spring, and a deployable and retractable cutter. The piston is located in the upper part of the cutter system body and moves axially through hydraulic drive. The fluid passage penetrates through the piston and extends along the axial direction of the cutter system body. The cutter is rotatably arranged on the cutter system body. When the hydraulic pressure reaches the threshold value, the piston moves downward to push the cutter to expand outward around the pivot. The spring is sleeved between the piston rod of the piston and the cutter system body, and the spring is used to apply a pre-tightening force to keep the cutter closed.

[0016] The integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations of the present invention integrates the pull-off sealing device, the hydraulic cutter system, and the cement retaining device, combines the functions of the hydraulic casing cutter and the cementing device, realizes a seamless and streamlined process of single cutting and cementing the casing, realizes plugging the well section from bottom to top and recovering the cut casing, reduces the construction procedures, improves the construction efficiency, reduces the operation cost, and improves the safety and reliability of the operation at the same time. Therefore, the present invention integrates the functions of casing cutting and cement retaining, reduces the operation steps and time, and significantly improves the efficiency of the abandonment operation. Description of the Drawings

[0017] The present invention will be further described below with reference to the drawings and embodiments.

[0018] Figure 1 FIG. is a schematic structural view of the integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations in a first angle according to an embodiment of the present invention.

[0019] Figure 2 FIG. is a schematic structural view of the integrated tool of hydraulic cutter and retainer for oil and gas well abandonment operations in a second angle according to an embodiment of the present invention.

[0020] Figure 3Schematic structural diagram of a hydraulic cutter system according to an embodiment of the present invention.

[0021] Figure 4 Exploded view of a hydraulic cutter system according to an embodiment of the present invention.

[0022] Figure 5 Schematic structural diagram of a cement retaining device at a first angle according to an embodiment of the present invention.

[0023] Figure 6 Schematic structural diagram of a cement retaining device at a second angle according to an embodiment of the present invention.

[0024] Figure 7 Exploded view of a setting tool according to an embodiment of the present invention.

[0025] Figure 8 Exploded view of a retainer according to an embodiment of the present invention.

[0026] Figure 9 Schematic structural diagram of a pull - off type sealing device at a first angle according to an embodiment of the present invention.

[0027] Figure 10 Schematic structural diagram of a pull - off type sealing device at a second angle according to an embodiment of the present invention.

[0028] Figure 11 Schematic structural diagram of a rubber blocking plug in a first state according to an embodiment of the present invention.

[0029] Figure 12 Schematic structural diagram of a rubber blocking plug in a second state according to an embodiment of the present invention.

[0030] In the drawings:

[0031] 10 - Hydraulic cutter system, 11 - Piston, 12 - Spring

[0032] 13 - Cutter, 14 - Conical pipe, 20 - Cement retaining device

[0033] 21 - Setting tool, 22 - Retainer, 30 - Pull - off type sealing device

[0034] 31 - Rubber blocking plug, 32 - Tensile trigger metal rod, 211 - Pipe core

[0035] 212 - Reed, 213 - Spring block, 221 - Dynamic roller

[0036] 222 - Clamp, 223 - Static roller, 224 - Retaining pipe wall

[0037] 15 - Cutter system body Detailed implementation manners

[0038] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0039] Please refer to the accompanying drawings. It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size should still fall within the scope covered by the technical content disclosed in the present invention without affecting the effects that the present invention can produce and the purposes that can be achieved.

[0040] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to the present invention. In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

[0041] Please refer to Figures 1 to 12 As shown, a hydraulic cutter and retainer integrated tool for abandoned oil and gas well operations includes a hydraulic cutter system 10 for cutting the casing, which internally has a hydraulically driven piston 11, a spring 12, and a deployable and retractable cutter 13. A fluid passage is provided inside the hydraulic cutter system 10; a cement retaining device 20 includes a packer 21 and a retainer 22 for plugging the target well section and completing the cement squeezing operation; a pull - off sealing device 30 connects the hydraulic cutter system 10 and the retainer 22, and triggers the pull - off sealing device to block the fluid passage to separate the upper and lower compartments after the cement squeezing is completed by lifting the tool; wherein, the hydraulic cutter system 10 remains closed during the cement squeezing operation because the internal pressure does not reach the opening threshold, and after the cement squeezing operation is completed, the piston 11 is driven by high - pressure liquid to deploy the cutter 13 to cut the casing, and after cutting is completed, the cutter 13 is retracted by the spring 12.

[0042] The working principle of the integrated tool is as follows: After the drill pipe integrated tool is lowered to the target well section, it is fixed to the target well section by the clamp 222, and the setting operation of the retainer 22 is carried out; the pull - off type sealing device 30 designed inside the hydraulic cutter system 10 is responsible for blocking the fluid passage to separate the upper and lower cabins after the retainer 22 completes the cement squeezing operation; the hydraulic cutter 13 is driven by hydraulic pressure for operation, and the cutter 13 can be retracted after the operation to complete the operation. The integrated tool consists of three parts: the hydraulic cutter system 10, the cement retaining device 20, and the pull - off type sealing device 30. Among them, the hydraulic cutter system 10 is responsible for cutting the pipe string, the cement retaining device 20 is responsible for the plugging operation, and the pull - off type sealing device 30 is responsible for blocking the fluid passage to separate the upper and lower cabins after the plugging operation is completed.

[0043] In some embodiments of the present invention, as Figures 3 to 4 shown, the hydraulic cutter system 10 includes a cutter system body 15, a hydraulically driven piston 11, a spring 12, and a deployable and retractable cutter 13. The piston 11 is located at the upper part of the cutter system body 15 and moves axially through hydraulic drive. The fluid passage penetrates the piston 11 and extends along the axial direction of the cutter system body 15, and the fluid passage is connected to the external pump pressure system. When the hydraulic pressure reaches the threshold value, the piston 11 moves downward to push the cutter 13 to expand outward around the pivot axis to complete the casing cutting. The spring 12 is sleeved between the piston rod of the piston 11 and the cutter system body 15 and is in a compressed state under normal conditions. The spring 12 is used to apply a pre - tightening force to keep the cutter 13 closed. After cutting is completed, the hydraulic pressure decreases, and the spring 12 rebounds to push the piston 11 upward, driving the blade to retract inward into the internal groove of the cutter system body 15 to realize the reset of the cutter 13. The movement stroke between the spring 12 and the piston rod can be fixed by a limit ring. The cutter 13 is rotatably arranged on the cutter system body 15. For example, the cutter 13 is fixed to the cutter pillow of the cutter system body 15 through a hinge pin. When it expands, it is controlled by the balance of the thrust of the piston 11 and the pressure of the hydraulic overflow hole. After the cutter 13 expands, it is kept in the cutting state by a self - locking mechanism to ensure the stability of the cutting depth. After cutting is completed, the reset force of the spring 12 overcomes the residual hydraulic pressure, causing the cutter 13 to retract completely. The fluid passage penetrates the piston rod and the cutter system body 15. During the squeezing operation, the internal pressure does not reach the cutting threshold, and the pre - tightening force of the spring 12 maintains the cutter 13 closed; after the operation is completed, the pressure is increased to the threshold to trigger the movement of the piston 11. It should be noted that the hydraulic cutter system 10 can be set with reference to the prior art.

[0044] When the integrated tool of the hydraulic cutter and the retainer for abandoned oil and gas well operation of the present invention works, lowering the integrated device is the primary link of the operation. The integrated tool needs to be transported to the target well section through the drill pipe to ensure the accurate position of the cement retainer device 20. After positioning, the cement retainer device 20 performs cement squeezing operation. After pumping cement slurry through the drill pipe, start the anchoring mechanism of the cement retainer device. The retainer 22 can provide a certain setting pressure and anchoring force to ensure stable fixation in a high-pressure environment. Ensure the sealing performance. After ensuring the independent closure of the annulus system, slowly pressurize and gradually increase the pressure to 50% of the design value, observe the pressure stability, and then pressurize in segments to the target value. Finally, pressurize to 1.5 times the design value and maintain the target pressure for 30 minutes. Analyze the pressure curve to confirm that there is no abnormal fluctuation or excessive pressure drop, and the seal inspection is successful. After the seal inspection is completed, by lifting the integrated tool, the pull-off type sealing device 30 is triggered to block the fluid passage to separate the upper and lower compartments. Then, high-pressure liquid is injected into the cavity of the hydraulic cutter 13, and the liquid pump is started to generate the required high pressure. Under the action of the high-pressure liquid, the piston 11 starts to move downward. As the piston 11 moves downward, the internal cutting mechanism is activated and the cutter 13 unfolds. At this time, the sharp edge of the blade of the cutter 13 closely adheres to the target casing or pipe. Start the hydraulic cutter 13 and gradually start cutting the casing through a powerful cutting force. The hydraulic cutter 13 cuts the casing along the set cutting path until the cutting is completed. The whole process needs to monitor parameters such as pressure and flow rate in real time to ensure that no abnormality occurs during the cutting process. As the blade of the cutter 13 gradually cuts through the casing, the casing is finally completely cut open, and the cutting process of the hydraulic cutter 13 is completed. After the casing cutting is completed, there is high-pressure liquid inside the downhole tool. To release these pressures and prevent accidents in subsequent operations, a pressure relief operation is required. Stop pressurizing the tool compartment, and the pressure inside the compartment gradually decreases until the pressure drops to the safe range. After pressure relief, the hydraulic system inside the cutter 13 will push the piston 11 back to its original position through the spring 12. The return of the piston 11 is the prerequisite for the automatic retraction of the cutter 13, ensuring that the cutter 13 can return to its original state after cutting and be prepared for the next use. After the piston 11 returns to its original position, the cutter 13 will automatically retract and return to its original state. Retracting the cutter 13 can prevent it from interfering with the wellbore or other equipment during downhole operations and ensure the smooth progress of subsequent operations. Finally, lift and recover the integrated tool.

[0045] As can be seen from the above, the integrated tool of the hydraulic cutter and the retainer for the abandonment operation of oil and gas wells according to the present invention integrates the pull-off sealing device 30, the hydraulic cutter system 10, and the cement retaining device 20, combines the functions of a hydraulic casing cutter and a cementing device, realizes a seamless and streamlined process of single-cutting and cementing the casing, achieves bottom-up plugging of the well section and recovery of the cut casing, reduces construction procedures, improves construction efficiency, reduces operation costs, and at the same time improves the safety and reliability of the operation. Therefore, the present invention integrates the functions of casing cutting and cement retaining, reduces operation steps and time, and significantly improves the efficiency of abandonment operations.

[0046] It can be understood that the following points need to be considered in the design of the hydraulic cutter system 10: ① Design the structure of the hydraulic cutter 13 to ensure its stable operation under the action of high-pressure mud; ② Develop a hydraulic drive system to ensure that the piston 11 can accurately control the opening and retraction of the blade; ③ Optimize the blade material and shape to improve cutting efficiency and durability. The following points need to be considered in the design of the cement retaining device 20: ① Optimize the structural design of the retainer 22 to improve its sealing performance under high-pressure environments; ② Develop a connection method compatible with the hydraulic cutter system 10 to ensure the coordinated operation of the integrated tool. The following points need to be considered in the design of the pull-off sealing device 30: ① Design the structure of the pull-off sealing device 30 to ensure that the blocking plug can correctly fall into the designated position; ② Select suitable materials to ensure the performance of the sealing device under high-pressure and high-temperature environments; ③ Conduct sealing performance tests to ensure effective plugging of the pipeline after pulling off to prevent leakage of high-pressure liquid.

[0047] The cement retaining device 20 uses mature technology. The integrated tool completes the cement squeezing operation through the cement retaining device 20, and the hydraulic cutter system 10 is in the closed state during the operation of the cement retaining device 20. As Figures 5 to 8As shown, the cement retaining device 20 is composed of a retainer 22 and a setting device 21. The retainer 22 is composed of a clamp 222, a dynamic roller 221, a static roller 223, and a retaining tube wall 224; wherein, the clamp 222: This is an important component of the retainer 22, which is used to fix and connect the various parts of the retainer 22 to ensure the stability and reliability of the retainer 22 during operation. Dynamic roller 221: The dynamic roller 221 can roll in the retaining tube wall 224. This design helps to achieve dynamic sealing and prevent cement slurry from leaking during squeezing. Static roller 223: Unlike the dynamic roller 221, the position of the static roller 223 is fixed. It cooperates with the dynamic roller 221 to jointly achieve the sealing function of the retainer 22. Retaining tube wall 224: This is the main part of the retainer 22, and other components such as the clamp 222, the dynamic roller 221 and the static roller 223 are installed on or inside it. The retaining tube wall 224 bears the pressure and weight of the cement slurry and is an important component of the retainer 22. The clamp 222 is distributed at both ends of the retainer 22, and wraps the outer edge of the retaining tube wall 224 through an annular locking structure to form an axial constraint. The clamp 222 adopts a petal design and is fixed to the retaining tube wall 224 by shear pins. It is covered by a special sheath to prevent displacement during transportation. In the sealing stage, the hydraulically driven push ring compresses the clamp 222 so that its teeth are embedded in the casing wall to achieve anchoring. The dynamic roller 221 assembly is integrated on the inner side of the retaining tube wall 224, located between the rubber tube and the clamp 222, and forms a movable connection with the tube wall through an axial slide groove. Under the action of hydraulic pressure, the dynamic roller 221 slides downward along the tube wall slide groove, driving the rubber tube to expand radially to form a seal. Its movement trajectory is limited by the guide groove of the tube wall to ensure that the expansion direction is controllable. The sealer 21 is composed of a tube core 211, a reed 212, and a spring block 213; wherein, the tube core 211: the tube core 211 is the core component of the sealer 21, which plays a role of connection and support. Through the tube core 211, the sealer 21 can achieve sealing and control of the pipeline. Reed 212: the reed 212 is an elastic element, which provides the sealing force required by the sealer 21. During the operation of the sealer 21, the reed 212 can maintain a certain elasticity to ensure the stability and sealing effect of the sealer 21 in downhole operations. When the reed 212 is stretched and fixed in the casing, the cutting knife 13 can be stretched and rotated, thereby achieving efficient cutting of the casing. Spring block 213: the spring block 213 is used to assist in sealing and positioning. It ensures that the sealer 21 can remain stable during downhole operations to prevent sealing failure caused by vibration or impact. The tube core 211 serves as the axial support body of the setting device 21 and penetrates the body of the setting device 21. Specifically, the tube core 211 is connected to the center tube of the retainer 22 by threads, and the separation tension between the tube core 211 and the center tube of the retainer 22 is set by the thread preload.It is internally provided with a fluid passage, which communicates with the injection passage of the cement retainer 22 and is used for conveying high-pressure liquid. An annular groove is provided on the outer wall of the core 211 for installing the reed 212 and the spring block 213 assembly. The depth of the groove matches the compression amount of the reed 212 to ensure the sealing force. The reed 212 is in an annular laminated structure and is sleeved in the groove of the core 211, generating a radial elastic deformation through pre-compression. Its outer side contacts the inner wall of the housing of the setting packer 21 to form a dynamic sealing interface. The end of the reed 212 is provided with a buckle structure, which engages with the limiting protrusion of the spring block 213 to prevent the reed 212 from undergoing axial displacement under high pressure. The spring blocks 213 are symmetrically distributed on both sides of the groove of the core 211 and are connected to the core 211 through spring pins 12. Under normal conditions, it remains in a contracted state under the pressure of the reed 212. When the core 211 is subjected to an axial thrust, the spring blocks 213 pop outwards and are embedded in the housing card slot to achieve setting and locking. The surface of the spring block 213 is provided with a wedge-shaped guiding surface, which forms a self-locking structure with the housing card slot to ensure that it cannot be unlocked automatically after setting. During setting, the fluid pressure pushes the core 211 to move axially, driving the reed 212 to be compressed to generate a radial sealing force, and at the same time triggering the outward expansion of the spring blocks 213 to complete mechanical locking. During the unsealing stage, the core 211 is lifted by a tool to make the spring blocks 213 disengage from the card slot, and the elastic recovery of the reed 212 drives the assembly to reset. The core 211, as the core carrier for power transmission and fluid passage, fixes the reed 212 and the spring blocks 213 through the groove; the reed 212 provides the elastic force required for dynamic sealing, and the spring blocks 213 realize the mechanical locking function. The three achieve reliable sealing and rapid response of the setting packer 21 in a high-pressure environment through precise cooperation. The retainer 22 and the setting packer 21 together constitute the cement retaining device 20. The retainer 22 realizes effective sealing and support through components such as the clamp 222, the dynamic roller 221, the static roller 223, and the retainer pipe wall 224; while the setting packer 21 ensures stability and sealing effect during downhole operations through components such as the core 211, the reed 212, and the spring blocks 213. This clearly defined structural design ensures the high efficiency and reliability of the cement retaining device 20 during operation.

[0048] Specifically and optionally, the upper end of the setting packer 21 is threadedly connected to the hydraulic cutting tool system 10, and the lower end of the setting packer 21 is threadedly connected to the retainer 22. After the integrated tool is lowered into the well, a releasing operation will be performed on the retainer, such as by rotating the setting packer 21 and the hydraulic cutting tool system 10 to separate the setting packer 21 and the hydraulic cutting tool system 10 from the retainer 22. In some embodiments of the present invention, such as Figure 7As shown, the setting packer 21 includes a core 211, a reed 212, and a spring block 213. A fluid passage is provided inside the core 211. An annular groove is provided on the outer wall of the core 211 for installing the reed 212 and the spring block 213. One end of the core 211 is connected to the hydraulic cutting tool system 10, and the other end of the core 211 is connected to the retainer 22. Specifically, optionally, the core 211 and the retainer 22 are connected by threads, and the separation tension between the core 211 and the retainer 22 is set by the thread pre-tightening force.

[0049] In some embodiments of the present invention, as Figure 8 shown, the retainer 22 includes a dynamic roller 221, and a clamp 222, a static roller 223, and a retainer pipe wall 224 sleeved outside the dynamic roller 221. The clamp 222 and the retainer pipe wall 224 are respectively provided on both sides of the static roller 223. The retainer pipe wall 224 is located between the static roller 223 and the clamp 222. The other end of the core 211 extends into the dynamic roller 221 to connect to the retainer 22. The tension-triggered metal rod 32 passes through the core 211 and connects to the retainer 22. Specifically, optionally, each retainer pipe wall 224 is composed of two half rings and is fixed together by a clamp 222.

[0050] In some embodiments of the present invention, as Figures 9 to 12 shown, the pull-off type sealing device 30 includes a rubber blocking plug 31 and a tension-triggered metal rod 32. The rubber blocking plug 31 is arranged in the fluid passage of the hydraulic cutting tool system 10. One end of the tension-triggered metal rod 32 is connected to the rubber blocking plug 31, and the other end of the tension-triggered metal rod 32 passes through the setting packer 21 and then connects to the retainer 22. When the tool is lifted to a predetermined tension, the tension-triggered connecting rod and the blocking plug are pulled off and separated, thereby triggering the rubber blocking plug 31 to block the fluid passage to achieve the isolation of the upper and lower cabins. It should be noted that the pull-off type sealing device 30 can be integrally formed with the retainer 22.

[0051] The pull-off type sealing device 30 is responsible for blocking the fluid passage to achieve the isolation of the upper and lower cabins after the cement squeezing operation is completed. The pull-off type sealing device 30 is composed of a rubber blocking plug 31 and a tension-triggered metal rod 32, and connects the hydraulic cutting tool system 10 and the retainer 22 through threaded connection. The tension-triggered metal rod 32 is connected to the retainer 22; after the cement squeezing operation is completed, it is lifted to a predetermined position, and the sealing blocking plug and the tension-triggered metal rod 32 are pulled off; the sealing blocking plug blocks the fluid passage, separating the upper cabin hydraulic cutting tool system 10 from the lower cabin cement retainer device 20.

[0052] In some embodiments of the present invention, as Figures 3 to 4As shown, the fluid passage of the hydraulic cutter system 10 includes an inverted conical pipe 14. The rubber blocking plug 31 seals the fluid passage through cooperation with the conical pipe 14 to isolate the upper and lower cabins. When the rubber blocking plug 31 is located at the large-diameter section of the conical pipe 14, the upper and lower cabins are connected. When the rubber blocking plug 31 is located at the small-diameter section of the conical pipe 14, the rubber blocking plug 31 is in sealing contact with the inner wall of the conical pipe 14. Specifically, optionally, the cone angle of the conical pipe 14 is 57° ± 2°, the surface roughness Ra ≤ 0.8 μm, and the rubber blocking plug 31 is made of high-temperature-resistant hydrogenated nitrile rubber with a Shore hardness of 85 ± 5. During the construction process, after lowering the integrated tool into the well, the retainer is released. At this time, the retainer has been separated from the main body part (hydraulic cutter system and packer). Then, while lifting the tool, cement is squeezed into the interior. After reaching a certain lifting height, the cement squeezing operation is completed. At this time, the blocking plug of the pull-breaking sealing device just contacts the conical channel, and then pull-breaking and plugging are carried out.

[0053] In some embodiments of the present invention, the pressure threshold required to open the cutter 13 is 45 Mpa to 50 Mpa. In a specific embodiment, the pressure required to open the hydraulic cutter system 10 is 50 MPa, and the maximum pressure generated inside the cutter 13 during the cement squeezing operation is 40 MPa. The pressure generated during the cement squeezing operation is not sufficient to push the piston 11, so the situation of the cutter 13 accidentally opening during cement squeezing will not occur. After the cement squeezing operation is completed, the integrated tool is lifted, triggering the pull-breaking sealing device 30 inside it. The blocking plug is separated from the tension-triggering metal rod 32, and the blocking plug seals the bottom of the hydraulic cutter 13, separating the upper and lower cabins of the integrated tool. High-pressure liquid is pumped into the hydraulic cutter 13. Since the contact areas of the upper and lower surfaces of the piston 11 with the high-pressure liquid are different, the pressure difference between the upper and lower surfaces of the piston 11 reaches 50 MPa, causing the piston 11 to move downward and deploy the cutter 13 for casing cutting operation. Specifically, optionally, the area ratio of the upper and lower surfaces of the piston 11 is 1.2:1 to 1.5:1. After cutting is completed, the pressurization inside the hydraulic cutter 13 is stopped, and the piston 11 slowly returns under the action of the spring 12, thereby retracting the cutter 13 to complete the operation. Specifically, optionally, the tension-triggering metal rod 32 is threadedly connected to the rubber blocking plug 31, and the separation tension between the tension-triggering metal rod 32 and the rubber blocking plug 31 is set through the threaded pre-tightening force to ensure triggering when the tool is lifted after the cement squeezing is completed.

[0054] The integrated tool workflow of the present invention includes: ①Lowering the device and squeezing cement. Lowering the integrated device is the primary step of the operation. The integrated tool needs to be conveyed to the target well section through the drill pipe. Combined with the reed 212, ensure that the setting position of the retainer 22 is accurate. At this time, perform the releasing operation on the retainer. At this time, the retainer has been separated from the hydraulic cutter system and the setting tool. After the positioning is completed, the cement retainer 22 performs the cement squeezing operation. While lifting the tool, squeeze cement into the inside. After reaching a certain lifting height, the cement squeezing operation is completed. For special situations, such as well leakage: If it is necessary to inject a plug in a well with severe leakage, it is necessary to plug the leak first and then carry out the next construction after meeting the plug injection conditions; For high-pressure wells: For high-pressure unstable wells or wells with large interlayer interference, pressure should be applied to wait for setting, generally applying a pressure of 3 - 5 MPa. ②Pressurizing for seal verification. After pumping cement slurry through the drill pipe, start the anchoring mechanism of the cement retainer 22. The retainer 22 can provide a certain setting pressure and anchoring force to ensure stable fixation in a high-pressure environment. Ensure the sealing performance. After ensuring that the annulus system is independently sealed, slowly pressurize and gradually pressurize to 50% of the design value, observe the pressure stability, and then pressurize in segments to the target value. Finally, pressurize to 1.5 times the design value and maintain the target pressure for 30 minutes. Analyze the pressure curve to confirm that there is no abnormal fluctuation or pressure drop exceeding the standard, and the seal verification is successful. ③Separating the cutting tool 13 and the retainer 22. After the seal verification is completed, trigger the pull-type sealing device 30 by lifting the integrated tool. The tension-triggered metal rod 32 separates from the blocking plug, and the blocking plug seals the pipeline inside the hydraulic cutter 13, isolating the upper hydraulic cutter 13 from the lower retainer 22 to prevent the backflow of cement slurry. It should be noted that after the cement squeezing operation is completed, the rubber blocking plug of the pull-type sealing device just contacts the conical channel, and then the pull-type sealing is carried out. ④Casing cutting. After the pull-type sealing device 30 is triggered and the blocking plug seals the pipeline inside the hydraulic cutter 13, inject high-pressure liquid into the cavity of the hydraulic cutter 13, start the liquid pump and generate the required high pressure. Under the action of the high-pressure liquid, the piston 11 starts to move downward. As the piston 11 moves downward, the internal cutting mechanism is activated and the cutter 13 unfolds. At this time, the sharp edge of the cutter 13 blade closely adheres to the target casing or pipeline. Activate the hydraulic cutter 13 and gradually start cutting the casing through a powerful cutting force. The hydraulic cutter 13 gradually cuts the casing along the set cutting path until the cutting is completed. The whole process needs to monitor parameters such as pressure and flow rate in real time to ensure that no abnormalities occur during the cutting process. As the cutter 13 blade gradually cuts through the casing, the casing is finally completely cut open, and the cutting process of the hydraulic cutter 13 is completed. ⑤Completing the operation and retrieving the tool. After the casing cutting is completed, there is high-pressure liquid inside the downhole tool. To release these pressures and prevent accidents in subsequent operations, a pressure relief operation is required. Stop pressurizing the tool cabin, and the pressure inside the cabin gradually decreases until the pressure drops to the safe range. After pressure relief, the hydraulic system inside the cutter 13 will push the piston 11 back to its original position through the spring 12.The return of the piston 11 is a prerequisite for the automatic retraction of the cutter 13, ensuring that the cutter 13 can return to its original state after cutting and be ready for the next use. After the piston 11 returns to its position, the cutter 13 will automatically retract and return to its original state. Retracting the cutter 13 can prevent it from interfering with the wellbore or other equipment during downhole operations and ensure the smooth progress of subsequent operations. Finally, lift the integrated recovery tool.

[0055] Through innovative design, the present invention integrates the hydraulic cutter system 10 with the cement retaining device 20 to achieve plugging the well section from bottom to top and recovering the cut casing. This tool mainly consists of three parts: the hydraulic cutter system 10, the cement retaining device 20, and the pull - off sealing device 30. It is lowered to the target well section through the drill pipe to complete operations such as cement squeezing and cutter 13 cutting. This integrated tool aims to improve the efficiency and safety of oil and gas well abandonment operations and reduce operation costs. Through optimized design, it realizes the efficient cutting and automatic retraction functions of the hydraulic - driven blade, and develops the pull - off sealing device 30 to ensure reliable separation and sealing from the retainer 22 after the cement squeezing is completed. This tool has multiple advantages, including reducing construction procedures, lowering operation costs; improving the safety and reliability of operations; adapting to various scenarios, such as the large - inner - diameter channel design allowing cementing operations or pumping operations before activating the cutting function; and having efficient cutting performance and good sealing performance.

[0056] The above - described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A hydraulic cutter and retainer integrated tool for oil and gas well abandonment operations, characterized in that: include, A hydraulic cutter system (10) is used for cutting casing, and is provided with a hydraulically driven piston (11), a spring (12) and a deployable and retractable cutter (13) inside the hydraulic cutter system (10), wherein a fluid channel is provided inside the hydraulic cutter system (10); a cement retaining device (20) comprises a setting device (21) and a retaining device (22), and is used for plugging a target well section and completing a cement squeezing operation; A breakaway sealing device (30) is connected to the hydraulic cutter system (10) and the retainer (22), and after the cement is squeezed, the breakaway sealing device (30) is triggered to block the fluid passage to separate the upper and lower cabins; The hydraulic cutter system (10) remains closed during cement squeezing operation because the internal pressure does not reach the opening threshold. After the cement squeezing operation is completed, the piston (11) is driven by high-pressure liquid to expand the cutter (13) to cut the casing. After the cutting is completed, the spring (12) is used to reset and retract the cutter (13).

2. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 1, characterized in that: The pressure threshold required for opening the cutting knife (13) is 45 MPa to 50 MPa.

3. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 1, characterized in that: The piston (11) has different upper and lower surfaces.

4. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 3, characterized in that: The area ratio of the upper and lower surfaces of the piston (11) is 1.2:1 to 1.5:

1.

5. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 1, characterized in that: The pull-off sealing device (30) comprises a rubber blocking plug (31) and a tension-triggered metal rod (32). The rubber blocking plug (31) is arranged in the fluid channel of the hydraulic cutter system (10). One end of the tension-triggered metal rod (32) is connected to the rubber blocking plug (31). The other end of the tension-triggered metal rod (32) passes through the setting device (21) and is connected to the retaining device (22). When the lifting tool reaches a predetermined tension, the tension-triggered metal rod (32) is pulled off and separated from the rubber blocking plug (31). The rubber blocking plug (31) blocks the fluid channel to achieve isolation between the upper and lower cabins.

6. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 5, characterized in that: The fluid passage of the hydraulic cutter system (10) comprises an inverted tapered pipe (14), and the rubber blocking plug (31) blocks the fluid passage by cooperating with the tapered pipe (14) to achieve isolation between the upper and lower cabins.

7. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operation according to claim 5, characterized in that: The pulling force that triggers the separation of the metal rod (32) and the rubber blocking plug (31) is set by the thread preload.

8. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operations according to any one of claims 1 to 7, characterized in that: The sealing device (21) comprises a tube core (211), a spring (212), and a spring block (213); a fluid channel is provided inside the tube core (211); an annular groove is provided on the outer wall of the tube core (211); the annular groove is used to install the spring (212) and the spring block (213); one end of the tube core (211) is connected to the hydraulic cutter system (10), and the other end of the tube core (211) is connected to the retainer (22).

9. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operations according to any one of claims 1 to 7, characterized in that: The retainer (22) comprises a dynamic roller (221), a clamp (222) sleeved on the outside of the dynamic roller (221), a static roller (223) and a retaining tube wall (224), wherein the clamp (222) and the retaining tube wall (224) are respectively provided on both sides of the static roller (223), and the retaining tube wall (224) is located between the static roller (223) and the clamp (222).

10. The integrated hydraulic cutter and retainer tool for oil and gas well abandonment operations according to any one of claims 1 to 7, characterized in that: The hydraulic cutter system (10) comprises a cutter system body (15), a piston (11) located at the upper part of the cutter system body (15), and moving axially by hydraulic drive, a fluid channel penetrating the piston (11) and extending along the axial direction of the cutter system body (15), a cutter (13) being rotatably arranged on the cutter system body (15), when the hydraulic pressure reaches a threshold value, the piston (11) moves downward to push the cutter (13) to expand outward around a pivot, a spring (12) is sleeved between the piston (11) rod of the piston (11) and the cutter system body (15), and the spring (12) is used to apply a pre-tightening force to the cutter (13) to keep it closed.

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