A hydraulic force increasing short joint applied to slip fishing tool

Abstract

A slip retrieval tool using a hydraulic booster sub, belonging to the field of oil drilling tools, includes an upper connector, a guide sleeve, a guide shoe, a retrieval cylinder, and a hydraulic booster sub. The hydraulic booster sub further includes a cylinder liner, a connecting sleeve, a piston, a central bushing, a pusher sleeve, a spring, and a retaining ring. The cylinder liner and the connecting sleeve are connected. The retaining ring is embedded in the upper part of the cylinder liner, and the central bushing is connected to the lower end of the retaining ring. The piston and the pusher sleeve are externally fitted. A spring is embedded between the pusher sleeve and the connecting sleeve. The upper connector is connected to the cylinder liner. The guide sleeve and the guide shoe are sequentially connected to the lower end of the connecting sleeve. An internal beveled thread is formed on the inner circumferential surface of the guide sleeve. The retrieval cylinder is installed inside the guide sleeve. An anti-rotation mechanism is provided between the retrieval cylinder and the guide sleeve. Under the action of the spring, the upper end face of the retrieval cylinder and the lower end face of the pusher sleeve correspond to form a contact fit and generate a relative guided downward movement stroke. When applied to retrieval operations, it can improve the retrieval effect, reduce operational risks, and ensure production safety.

Description

[0001] This utility model is a divisional application of the earlier utility model application filed on December 10, 2024, with application number 2024230370187 and title "A hydraulic booster sub that can maintain well fluid circulation". Technical Field

[0002] This utility model relates to the field of oil drilling tools, specifically to a slip retrieval tool using a hydraulically amplified short section. Background Technology

[0003] In oilfield drilling, maintaining downhole mud circulation through wellhead pump pressure control is an essential technical step in the drilling production process. Utilizing circulating mud to clean the wellbore, fix the borehole, stabilize well pressure, and protect the environment not only ensures the safety and efficiency of drilling operations but also benefits environmental protection and the effective utilization of resources. With continuous technological advancements, the mud pressure pumped from the wellhead in oilfield production is often used as additional auxiliary power for downhole operations to ensure operational effectiveness and improve production efficiency. Patent CN104514507B discloses a "hydraulic-assisted retrieval tool" that uses well fluid pressure to assist in retrieving the inner cylinder of a plug-free tool. The disclosed technical solution of this "hydraulic-assisted retrieval tool" involves throwing a ball into the inner cavity of the central tube to block the inner cavity, thus blocking the drilling tool's mud circulation channel, providing additional lifting force to the central tube and assisting in the retrieval operation of the plug-free tool's inner cylinder. As is well known, the drilling mud circulation channel is not only a component of the downhole mud circulation system but also a safety channel for downhole pressure control. In the event of a well kick or blowout during operations, the wellhead must be immediately sealed, and drilling mud must be pumped into the downhole pump through the drilling mud circulation channel for well control to prevent major oilfield production accidents. Therefore, while the existing "hydraulic-assisted fishing tool" technology can assist downhole fishing operations, the complete closure of the drilling mud circulation channel during fishing makes it impossible to respond promptly to well kicks or blowouts, potentially leading to production accidents. This presents significant risk protection deficiencies and safety hazards, failing to meet oilfield production requirements. Therefore, it is necessary to research and develop new downhole hydraulic-assisted tools that, while ensuring unobstructed drilling mud circulation, utilize well fluid pressure to provide additional operating power to the downhole tools, thus solving the problems of existing technologies. Utility Model Content

[0004] The purpose of this invention is to provide a slip retrieval device that uses a hydraulically amplified short section to provide axial thrust to the retrieval tool while ensuring the circulation of mud in the well, thereby improving the retrieval effect, reducing operational risks, and ensuring production safety.

[0005] A hydraulic booster sub for maintaining well fluid circulation includes: a cylinder liner, a connecting sleeve, a piston, a central bushing, a pusher sleeve, a spring, and a retaining ring. The cylinder liner and the connecting sleeve are both cylindrical bodies, connected vertically to form the sub's main body. Mechanical connection structures are provided at the upper end of the cylinder liner and the lower end of the connecting sleeve to connect the sub's main body to drilling tools. The retaining ring is axially limited and sealed within the upper part of the cylinder liner's inner cavity. The central bushing has an axially penetrating well fluid channel and is coaxially disposed within the inner cavity of the sub's main body, providing a sealed fit. Fixedly connected to the lower end of the fixed ring, the upper part of the internal well fluid channel is a large-diameter region, and the lower part is a small-diameter region with abrupt reduction in pore size. At the abrupt reduction in pore size between the large-diameter region and the small-diameter region, the circulating well fluid will experience a local increase in fluid pressure due to flow restriction. The piston and the pusher sleeve are sequentially fitted from top to bottom on the outside of the central bushing. The piston is axially limited and embedded in the hydraulic cylinder sleeve, and has a pusher stroke distance H2 relative to the central bushing for vertical movement. The inner and outer sides are respectively connected to the central bushing and the hydraulic cylinder sleeve. The cylinder sleeve and the central bushing form a sealing fit, sealing the annular space between the cylinder sleeve and the central bushing while also dividing the annular space into an independently sealed injection space and a drainage space. In the injection space, the central bushing has an injection hole penetrating the sidewall of the large-diameter area to transmit well fluid pressure from inside the central bushing into the injection space. In the drainage space, the cylinder sleeve has a drainage hole penetrating the sidewall to balance the well fluid pressure between the drainage space and the outside of the cylinder sleeve. The upper end of the pusher sleeve... The hydraulic cylinder liner is sealed to the connecting sleeve, and its lower end extends beyond the end of the connecting sleeve. The connecting sleeve limits the upward travel of the push sleeve. An annular spring device groove is provided between the push sleeve body and the connecting sleeve. The spring is fitted into the spring device groove and supported between the hydraulic cylinder liner and the push sleeve, applying an elastic force to the push sleeve relative to the hydraulic cylinder liner. The push sleeve limits the static space state of the push sleeve. In the static space state, the push sleeve has a reverse travel distance H1 relative to the connecting sleeve that moves upward.

[0006] The hydraulic booster sub that can maintain well fluid circulation preferably has an annular strain space between the lower end face of the piston and the upper end face of the pusher sleeve. A strain ring is embedded in the strain space. The strain ring is made of a metal material with a specific yield strength and its radial width Δr is smaller than the radial width ΔR of the strain space. A radial adaptive filling space is reserved in the strain space when the strain ring is subjected to axial compression deformation.

[0007] The hydraulic booster sub that can maintain well fluid circulation preferably has a spring pad in the spring device groove. The spring pad is located at the bottom of the spring device groove, so that one end of the piston is supported on the spring pad. The spring pad applies an elastic force to the push sleeve, thereby enhancing the stability and reliability of the elastic force application.

[0008] The hydraulic booster sub that maintains well fluid circulation is preferably installed inside the central bushing on a narrowing shoulder formed by the abrupt reduction in diameter between the large-diameter region and the small-diameter region. The flow-limiting plug has a central shaft hole that is vertically connected, and the diameter of this hole is smaller than the diameter of the small-diameter region in the well fluid channel of the central bushing. The flow-limiting plug is detachably connected to the central bushing to further preset and adjust the diameter of the small-diameter region at the abrupt reduction in diameter position in the well fluid channel of the central bushing. This controls the increase in local fluid pressure caused by the flow restriction at the abrupt reduction in diameter position between the large-diameter region and the small-diameter region, thereby regulating the pushing force exerted by the well fluid flow on the pusher sleeve to meet the process requirements for controlled force enhancement of downhole tools during drilling production.

[0009] A slip retrieval device using a hydraulic booster sub includes: an upper connector, a guide sleeve, a guide shoe, a retrieval cylinder, and a hydraulic booster sub capable of maintaining well fluid circulation. The upper connector is fitted to the upper end of the hydraulic cylinder sleeve, and its lower end is limited and fixed by a retaining ring embedded in the hydraulic cylinder sleeve. The upper end is provided with a mechanical connection structure for interconnection with drilling tools. The guide sleeve and the guide shoe are sequentially connected to the lower end of the connecting sleeve. An internal inclined thread is formed on the inner circumferential surface of the guide sleeve. The retrieval cylinder is a circular cylinder with a stop groove at the lower end and radial elastic deformation capability at the lower part. The stop groove is evenly distributed along the circumference of the cross-section of the retrieval cylinder, and an external inclined thread is provided on the outer circumferential surface. The external inclined thread is connected to the guide sleeve. The internal inclined thread structures on the upper part correspond to each other, and inverted teeth are provided on the inner circumference. The retrieval cylinder is installed inside the guide sleeve through the mutual cooperation of the external inclined thread and the internal inclined thread. An anti-rotation mechanism is provided between the retrieval cylinder and the guide sleeve to limit the circumference of the retrieval cylinder relative to the guide sleeve. Under the action of the elastic force of the spring, the upper end face of the retrieval cylinder and the lower end face of the push sleeve form an elastic contact fit, and the cylinder moves downward relative to the guide sleeve due to the push of the push sleeve. At the same time, through the interaction between the corresponding spiral conical surfaces on the internal and external inclined threads, the lower part of the retrieval cylinder undergoes initial elastic radial contraction deformation, and the inner diameter is reduced.

[0010] The aforementioned slip retrieval device using a hydraulically amplified short section preferably has a milling head installed inside the guide sleeve. The milling head is located at the lower part of the retrieval cylinder and is kept in a circumferentially limited position relative to the guide sleeve. Before the fish that has fallen into the well through the guide shoe enters the retrieval cylinder, the fish head is cleaned and trimmed in advance, improving the fit between the fish and the retrieval cylinder and enhancing the retrieval effect.

[0011] The aforementioned hydraulically amplified short section retrieval device preferably has a milling head located at the lower part of the retrieval cylinder, threadedly connected and installed inside the guide sleeve, with an anti-rotation pin at its upper end. Simultaneously, anti-rotation grooves, overlapping in position and corresponding to the anti-rotation pin, are respectively formed on the guide sleeve and the retrieval cylinder. The anti-rotation pin is fitted into the two overlapping anti-rotation grooves on the guide sleeve and the retrieval cylinder, simultaneously providing circumferential positioning of the retrieval cylinder and the milling head relative to the guide sleeve.

[0012] The beneficial effects of this utility model are that it provides a hydraulic booster sub that can maintain well fluid circulation and a slip retrieval device using the hydraulic booster sub. The hydraulic booster sub adopts a structure in which the well fluid channel diameter in the central bushing suddenly narrows, causing the local mud fluid pressure at the location of the sudden diameter narrowing to increase due to the confined flow effect. Under the premise of not affecting the smooth connection of the well fluid channel and ensuring the normal circulation of the mud fluid, the local high-pressure mud fluid is used to transmit the well fluid pressure to the injection space. The hydraulically driven piston transmits axial force to the push sleeve, and the push sleeve provides additional pushing force to the downhole drilling tool connected to the lower end of the hydraulic booster sub, improving the process performance of the downhole drilling production tool. At the same time, maintaining the smooth connection of the well fluid channel and being able to start mud fluid circulation at any time can also reduce the risk of well blowout accidents. The slip retrieval device using the hydraulic booster sub can reduce the operation risk and ensure production safety while increasing the retrieval effect. Attached Figure Description

[0013] Figure 1 Diagram of a hydraulic booster section that maintains well fluid circulation.

[0014] Figure 2 for Figure 1 Sectional view along line AA.

[0015] Figure 3 A basic structural diagram of a slip retrieval device using a hydraulically amplified short section.

[0016] Figure 4 for Figure 3 Sectional view along the BB line.

[0017] Figure 5 This is a structural diagram of the salvage device using a hydraulically amplified short section in the salvage state.

[0018] Figure 6 This is a structural diagram of the increased-force state of the slip retrieval device using a hydraulically amplified short section.

[0019] Among them: 1 is the hydraulic cylinder sleeve, 2 is the connecting sleeve, 3 is the piston, 4 is the central shaft sleeve, 5 is the push support sleeve, 6 is the spring, 7 is the spring pad, 8 is the fixing ring, 9 is the strain ring, 10 is the flow limiting plug, 11 is the upper connector, 12 is the guide sleeve, 13 is the guide shoe, 14 is the fishing tube, 15 is the milling head, 16 is the injection hole, 17 is the drainage hole, 18 is the injection space, 19 is the drainage space, 20 is the downhole fish, and 21 is the anti-rotation pin. Detailed Implementation

[0020] Furthermore, in conjunction with specific embodiments and their accompanying drawings... Figures 1 to 6 The present invention provides a detailed description of the technical solution for which protection is sought.

[0021] A type of slip retrieval device that utilizes a hydraulically amplified short section, such as Figures 3 to 6 As shown, it consists of a hydraulic cylinder liner 1, a connecting sleeve 2, a piston 3, a central shaft sleeve 4, a pusher sleeve 5, a spring 6, a spring washer 7, a retaining ring 8, a strain gauge ring 9, a flow restrictor 10, an upper connector 11, a guide sleeve 12, a guide shoe 13, a retrieval cylinder 14, and a milling head 15, wherein: as... Figure 1 and Figure 2 As shown, the hydraulic cylinder sleeve 1, the connecting sleeve 2, the piston 3, the central shaft sleeve 4, the pusher sleeve 5, the spring 6, the spring pad 7, the fixing ring 8, the strain ring 9, and the flow limiting plug 10 constitute a hydraulic booster sub that can maintain well fluid circulation.

[0022] The upper connector 11, the hydraulic cylinder sleeve 1, the connecting sleeve 2, the guide sleeve 12, and the guide shoe 13 are sequentially connected by threaded engagement. The upper end of the upper connector 11 is provided with an internal thread for connecting the drill rod of the drill string. An internal inclined thread is formed on the inner circumferential surface of the guide sleeve 12. The upper and lower ends of the fixing ring 8 are respectively limited by the upper connector 11 and the hydraulic cylinder sleeve 1, and are sealed and fixedly embedded in the upper inner cavity of the hydraulic cylinder sleeve 1. The central bushing 4 is coaxially arranged, sealed and fixedly connected to the lower end of the fixing ring 8, and has an axially penetrating well fluid channel inside. The upper part of the well fluid channel is a large-diameter area. The lower part of the central sleeve 4 is a small-diameter region with a smaller aperture than the large-diameter region, extending into the guide sleeve 12. A flow-limiting plug 10 is installed on the radial reduction shoulder between the large-diameter region and the small-diameter region. The flow-limiting plug 10 is used to preset and further control and adjust the flow-limiting aperture of the small-diameter region in the central sleeve 4 to the well fluid channel. The piston 3, the strain ring 9, and the pusher sleeve 5 are sequentially fitted from top to bottom on the outside of the central sleeve 4. The piston 3 is axially limited and embedded in the hydraulic cylinder sleeve 1, and its inner and outer sides respectively form a sealing fit with the central sleeve 4 and the hydraulic cylinder sleeve 1, thus sealing the hydraulic cylinder sleeve. The annular space between the piston 1 and the central sleeve 4 is divided into an independently sealed injection space 18 and a drainage space 19. Two through-wall injection holes 16 are provided on the central sleeve 4 to connect the injection space 18 with the large-diameter area in the well fluid channel of the central sleeve 4. Two through-wall drainage holes 17 are provided on the cylinder sleeve 1 to connect the drainage space 19 with the outside of the cylinder sleeve 1. The piston 3 has an axial movement stroke relative to the central sleeve 4 within the cylinder sleeve 1. The upper end of the pusher sleeve 5 is correspondingly and sealingly fitted with the cylinder sleeve 1, and the lower end is fitted with the central sleeve 4. It should extend into the guide sleeve 12. The push sleeve 5 and the connecting sleeve 2 form an annular spring device groove. The spring 6 and the spring pad 7 are inlaid in the spring device groove. The spring pad 7 is located at the bottom of the spring device groove. The spring 6 is supported between the hydraulic cylinder sleeve 1 and the spring pad 7, and applies an elastic force to the push sleeve 5 relative to the hydraulic cylinder sleeve 1. The strain ring 9 is made of lead alloy material with low yield strength and is located in the annular strain space between the lower end face of the piston 3 and the upper end face of the push sleeve 5. The radial width Δr is smaller than the radial width ΔR of the strain space.The retrieval cylinder 14 has six stop grooves with lower openings on its body. These stop grooves are arranged axially along the circumference of the retrieval cylinder 14 and are evenly distributed. An external inclined thread is provided on the outer circumference of the retrieval cylinder 14, which corresponds to the internal inclined thread structure on the guide sleeve 12. Inverted teeth are provided on the inner circumference. The retrieval cylinder 14 is installed inside the guide sleeve 12 through the mutual cooperation of the external and internal inclined threads. The upper end face of the cylinder is connected to the lower end of the push-support sleeve 5, which extends into the guide sleeve 12 under the action of the spring 6. The milling head 15 is located at the lower part of the retrieval cylinder 14 and is threadedly connected to the guide sleeve 12. It has milling teeth on its lower annular surface and an anti-rotation pin 21 on its upper end. Anti-rotation grooves, overlapping each other and corresponding to the anti-rotation pin 21, are respectively formed on the guide sleeve 12 and the retrieval cylinder 14. The anti-rotation pin 21 is fitted into the two overlapping anti-rotation grooves on the guide sleeve 12 and the retrieval cylinder 14, thus circumferentially limiting the rotation of both the retrieval cylinder 14 and the milling head 15 relative to the guide sleeve 12.

[0023] The following is the operation method for retrieving fish that have fallen into the well using a slip retrieval device with a hydraulic booster sub, as described in this embodiment:

[0024] Step 1. Before the oilfield salvage operation, first assemble the aforementioned slip salvage device using a hydraulically amplified short section at the surface wellhead, making it appear as... Figure 3 The basic structural state is shown. Then, the upper connector 11 is threadedly connected to the drill string and sent down the well. During the sending process, mud is pumped through the wellhead to maintain the normal state of well fluid circulation.

[0025] Step 2. When the hydraulically amplified short section slip retrieval device is lowered to the retrieval position, the drill pipe is rotated to guide the downhole fish 20 into the guide shoe 13. Simultaneously, the milling head 15 is used to clean and mill the head of the downhole fish 20 as needed. The drill pipe continues to be lowered. Because the diameter of the downhole fish 20's head is larger than the initial inner diameter of the retrieval cylinder 14, the downhole fish 20 will push the retrieval cylinder 14 and the pusher sleeve 5 to overcome the elastic force of the spring 6 and move upwards along the central shaft sleeve 4. During this movement, the radial constraint of the guide sleeve 12 on the retrieval cylinder 14 gradually decreases, and the lower elastic diameter gradually recovers. When the borehole diameter is enlarged to correspond to the head of the downhole fish 20, the downhole fish 20 can enter the inner hole of the retrieval tube 14. The drill string is then lowered to fully insert the downhole fish 20 into the retrieval tube 14. Afterward, the drill string is raised, and the initial friction between the downhole fish 20 and the retrieval tube 14 pulls the retrieval tube 14 downward relative to the guide sleeve 12. During this downward movement, constrained by the radial limit of the guide sleeve 12, the retrieval tube 14 gradually tightens around the downhole fish 20 and pulls it upward with the drill string. During this process, the slip retrieval device using a hydraulically amplified short section exhibits the following characteristics: Figure 5 The salvage structure state is shown below;

[0026] Step 3. When the head structure of the retrieved "fish 20" (a type of fishing tool) is complex and cannot form an ideal clamping fit with the retrieval cylinder 14, or when the weight of the "fish 20" is too large to guarantee a direct retrieval effect, increase the pumping pressure of the wellhead mud to 10-14 MPa. After the pumping pressure reaches the set value for the assist process, maintain it continuously. Utilize the high mud and well fluid pressure pumped from the wellhead to increase the clamping force of the retrieval cylinder 14 on the "fish 20". Simultaneously, while maintaining high-pressure mud and well fluid circulation, raise the drill string until the "fish 20" is retrieved from the well, completing the retrieval operation. During this process, the slip retrieval device using a hydraulically amplified short section exhibits the following characteristics: Figure 6 The shown is the stress-increasing structural state.

[0027] The working principle of the slip retrieval device using a hydraulic booster sub in this embodiment during the retrieval of fish that have fallen into the well is as follows: During the process of dropping the slip retrieval device using a hydraulic booster sub into the well in step 1, the well fluid circulation remains in a normal state. At this time, at the location where the orifice diameter suddenly narrows between the large-diameter area and the small-diameter area in the well fluid channel inside the central sleeve 4, the circulating well fluid will experience a local increase in fluid pressure due to flow restriction. The magnitude of this local increase in fluid pressure increases both with the degree of flow restriction in the small-diameter area and with the increase in the wellhead mud pump pressure. This locally increased fluid pressure can be transmitted into the injection space 18 through the injection hole 16 opened on the central sleeve 4, pushing the piston 3 along the central axis in the cylinder sleeve 1. The sleeve 4 moves downwards until it forms an elastic contact with the strain ring 9. Because the local pressure increase at the location of the abrupt reduction in orifice diameter in the well fluid channel under normal well fluid circulation conditions is small and insufficient to cause axial plastic deformation of the strain ring 9, it remains rigidly supported between the piston 3 and the push sleeve 5, transmitting the piston 3 to the push sleeve 5. The push sleeve 5 then pushes the retrieval cylinder 14 downwards relative to the guide sleeve 12, causing a slight displacement. Through the interaction between the inner inclined thread on the guide sleeve 12 and the outer inclined thread on the retrieval cylinder 14, after displacement, the lower part of the retrieval cylinder 14 undergoes elastic radial contraction deformation and generates an elastic force between it and the guide sleeve 12. This elastic force is axially balanced with the pushing force of the piston 3. Figure 3 As shown, the rigid assembly of the piston 3, the strain ring 9, and the retrieval cylinder 14, together with the guide sleeve 12, can form a stable static equilibrium structure. During the retrieval operation in step 2, when the downhole fish 20 interacts with the retrieval cylinder 14 in the retrieval position, the downhole fish 20 can simultaneously overcome the elastic force of the spring 6 and the driving force of the circulating well fluid in the injection space 18, such as... Figure 5As shown, the retrieval cylinder 14 is pushed upward relative to the guide sleeve 12 and eventually enters the retrieval cylinder 14 to capture the fish 20 that fell into the well. In step 3, during the pressurization process, the pumping pressure is increased to change the wellhead pumping mud into a pressurized well fluid circulation. Since the wellhead pump pressure usually needs to rise to 15-20 MPa in a short time during the transition, not only is the pressure increase large, but the pressure change gradient is also large. Therefore, the local fluid pressure at the location where the orifice diameter suddenly shrinks in the well fluid channel increases rapidly and significantly. This steep increase in fluid pressure is transmitted to the injection space 18 and strongly impacts the piston 3, which will inevitably cause the piston 3 to exert pressure on the strain ring. The driving force of strain ring 9 suddenly increases and instantaneously exceeds the yield strength of strain ring 9, causing plastic deformation of strain ring 9. The axial height is compressed and reduced, while the radial width increases, effectively mitigating the impact of piston 3. This prevents the impact of piston 3 from being directly transmitted to the retrieval cylinder 14 during the increase of wellhead mud pumping pressure, thus avoiding plastic deformation or breakage of the retrieval cylinder 14 and failure to complete the retrieval operation. As the pumping pressure enters the holding stage of the assist process set pressure, the plastically deformed strain ring 9 completely fills the strain space containing strain ring 9. At this time, the fluid flow pressure in the injection space 18 has become relatively stable. Figure 6 As shown, the strain ring 9 after plastic deformation can transmit the smooth and stable force of the piston 3 to the push sleeve 5, and apply additional pushing force to the retrieval cylinder 14 through the push sleeve 5, so as to help increase the force of the clamping sleeve to hold the fish 20 in the well, improve the retrieval effect, and enhance the stability and reliability of the retrieval operation.

[0028] Meanwhile, during the process of retrieving the fish 20 from the well using the slip retrieval device with hydraulic booster described in this embodiment, the fluid flow channels on the central axis of the interconnected upper connector 11, central bushing 4, retrieval cylinder 14, and milling head 15 remain unobstructed. Therefore, if a well kick or blowout occurs, it can be safely dealt with at any time, avoiding major safety accidents, reducing risks and hidden dangers, minimizing economic losses, and ensuring production safety.

Claims

1. A slip retrieval device using a hydraulically amplified short section, characterized in that, include: The upper connector (11), guide sleeve (12), guide shoe (13), retrieval tube (14), and hydraulic booster section; The hydraulic booster sub further includes: a cylinder sleeve (1), a connecting sleeve (2), a piston (3), a central bushing (4), a pusher sleeve (5), a spring (6), and a retaining ring (8); the cylinder sleeve (1) and the connecting sleeve (2) are both cylindrical bodies, connected to each other to form the main body of the sub; mechanical connection structures are respectively provided at the upper end of the cylinder sleeve (1) and the lower end of the connecting sleeve (2); the retaining ring (8) is axially limited and sealed and fitted into the upper part of the inner cavity of the cylinder sleeve (1); the central bushing (4) has an axially penetrating well fluid channel and is coaxially arranged... The inner cavity of the short section body is sealed and fixedly connected to the lower end of the fixing ring (8). The upper part of the well fluid channel inside is a large-diameter area, and the lower part is a small-diameter area with a sudden decrease in diameter. The piston (3) and the pusher sleeve (5) are sequentially fitted from top to bottom on the outside of the central bushing (4). The piston (3) is axially limited and embedded in the hydraulic cylinder sleeve (1), and has a relative movement stroke to the central bushing (4). The inner and outer sides respectively correspond to the central bushing (4) and the hydraulic cylinder sleeve (1) to form a sealing fit, sealing the hydraulic cylinder sleeve. (1) The annular space between the central bushing (4) and the central bushing (4) is divided into an independently sealed injection space (18) and a drainage space (19). In the injection space (18), the central bushing (4) has an injection hole (16) that penetrates the side wall of the large-diameter area. In the drainage space (19), the cylinder sleeve (1) has a drainage hole (17) that penetrates the side wall. The upper end of the pusher sleeve (5) is sealed to the cylinder sleeve (1), and the lower end extends beyond the end of the connecting sleeve (2). The connecting sleeve (2) limits the upward travel of the push sleeve (5). An annular spring device groove is provided between the push sleeve (5) and the connecting sleeve (2). The spring (6) is fitted in the spring device groove and supported between the hydraulic cylinder sleeve (1) and the push sleeve (5). An elastic force is applied to the push sleeve (5) relative to the hydraulic cylinder sleeve (1). The push sleeve limits the static space state of the push sleeve (5). In the static space state, the push sleeve (5) has a reverse travel distance H1 relative to the connecting sleeve (2) moving upward. The upper connector (11) is connected to the upper end of the hydraulic cylinder sleeve (1), and the lower end is fixed by a retaining ring embedded in the hydraulic cylinder sleeve (1). The upper end is provided with a mechanical connection structure. The guide sleeve (12) and the guide shoe (13) are connected to the lower end of the connecting sleeve (2) in sequence. An inner inclined thread is provided on the inner circumferential surface of the guide sleeve (12). The retrieval cylinder (14) is a circular cylinder with a stop groove at the lower end. The lower part has radial elastic deformation capability. The stop groove is evenly distributed along the circumference of the cross section of the retrieval cylinder (14). An outer inclined thread is provided on the outer circumferential surface. The outer inclined thread corresponds to the inner inclined thread structure opened on the guide sleeve (12). Inverted teeth are provided on the inner circumferential surface. The retrieval cylinder ( 14) The external inclined thread and the internal inclined thread are installed inside the guide sleeve (12) through mutual cooperation. An anti-rotation mechanism is provided between the retrieval cylinder (14) and the guide sleeve (12). The retrieval cylinder (14) is circumferentially limited relative to the guide sleeve (12). Under the action of the elastic force of the spring (6), the upper end face of the retrieval cylinder (14) and the lower end face of the push sleeve (5) are in elastic contact cooperation. The retrieval cylinder (14) is pushed by the push sleeve and moves downward relative to the guide sleeve (12). At the same time, through the interaction between the spiral conical surfaces of the internal inclined thread and the external inclined thread, the lower part of the retrieval cylinder (14) undergoes initial elastic radial shrinkage deformation, and the inner hole diameter is reduced.

2. The slip retrieval device using a hydraulically amplified short section as described in claim 1, characterized in that: An annular strain space is provided between the lower end face of the piston (3) and the upper end face of the push sleeve (5). A strain ring (9) is embedded in the strain space. The radial width Δr of the strain ring (9) is smaller than the radial width ΔR of the strain space. A radial adaptive filling space is reserved in the strain space when the strain ring (9) is subjected to axial compression deformation.

3. The slip retrieval device using a hydraulically amplified short section as described in claim 2, characterized in that: The strain ring (9) is made of lead alloy material.

4. The slip retrieval device using a hydraulically amplified short section as described in claim 3, characterized in that: A spring pad (7) is provided in the spring device groove. The spring pad (7) is located at the bottom of the spring device groove, so that one end of the piston (3) is supported on the spring pad (7), and an elastic force is applied to the push sleeve (5) through the spring pad (7).

5. The slip retrieval device using a hydraulically amplified short section as described in claim 4, characterized in that: Inside the central bushing (4), a flow restrictor (10) is installed on the diameter reduction shoulder formed by the abrupt reduction in diameter between the large-diameter region and the small-diameter region. The flow restrictor (10) has a central shaft hole that is connected vertically. The diameter of the central shaft hole is smaller than the diameter of the small-diameter region in the well fluid channel of the central bushing (4). The flow restrictor (10) is connected to the central bushing (4) in a detachable and replaceable manner.

6. A slip retrieval device using a hydraulically amplified short section as described in any one of claims 1 to 5, characterized in that: A milling head (15) is installed inside the guide sleeve (12). The milling head (15) is located at the lower part of the retrieval cylinder (14) and is kept circumferentially limited relative to the guide sleeve (12).

7. A slip retrieval device using a hydraulically amplified short section as described in claim 6, characterized in that: The milling head (15) is located at the lower part of the retrieval cylinder (14) and is threadedly connected to the guide sleeve (12). An anti-rotation pin (21) is provided at the upper end. At the same time, anti-rotation grooves that overlap with each other and correspond to the anti-rotation pin (21) are respectively opened on the guide sleeve (12) and the retrieval cylinder (14). The anti-rotation pin (21) is fitted into the two overlapping anti-rotation grooves opened on the guide sleeve (12) and the retrieval cylinder (14), and simultaneously limits the circumference of the retrieval cylinder (14) and the milling head (15) relative to the guide sleeve (12).

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