Hydraulically controlled self-resetting internal fishing tool and fishing method

Abstract

The application provides a liquid-controlled automatic reset internal fishing tool and a fishing method. The fishing tool comprises a fixed connecting mechanism and a movable locking mechanism. The fixed connecting mechanism comprises an upper joint, a connecting shaft, a throttle sleeve and a mandrel. The lower part of the upper joint is sleeved with an adjusting ring. The throttle sleeve is provided with a reset piston through hole and a releasing piston through hole in the radial direction. The outer wall of the mandrel is in contact with a locking claw. The movable locking mechanism comprises a reset piston, a releasing piston, a damping ring, a spring and a locking claw. The reset piston is located on the upper outer wall of the throttle sleeve and is in sealing contact with the connecting shaft and the throttle sleeve. The releasing piston is located on the lower outer wall of the throttle sleeve and is connected with the reset piston. The damping ring is arranged between the reset piston and the releasing piston and is locked with the throttle sleeve. The spring is arranged at the lower end of the releasing piston, and the locking claw is connected with the spring. The fishing method can be realized by the tool. The tool is unlocked and reset through hydraulic control, and the releasing action is completed under the condition of no pressure operation. The method is simple and easy to operate.

Description

Technical Field

[0001] This invention relates to the field of downhole tools technology in oil and gas fields, specifically to a hydraulically controlled, automatically reset internal retrieval tool and retrieval method. Background Technology

[0002] Currently, the retrieval and recovery of downhole tubular tools with internal retrieval necks, such as safety connectors, typically employs the GS retrieval tool. After successful reconnection and retrieval of the GS retrieval tool to the downhole tubular tool, if jamming occurs and the GS retrieval tool needs to be removed, pressure needs to be pumped into the tubing string. Under pressurized conditions, the GS retrieval tool can be lifted and released from the downhole tubular tool. The release of the GS retrieval tool must be performed under pressurized conditions, requiring pressurized operation equipment, which significantly increases operational costs and poses high well control safety risks. Therefore, providing a hydraulically controlled, automatically resettable internal retrieval tool and retrieval method is of great significance.

[0003] Chinese patent application number "CN201811055525.X" entitled "A Hydraulic Controlled Downhole Fishing Tool" discloses a hydraulic controlled downhole fishing tool. This tool mainly consists of a connector, sealing ring, sliding sleeve, fixing pin, piston, outer shell, steel balls, slips, mandrel, screw, return spring, travel pin, pin spring, and semi-circular key. During fishing operations, the tool is connected to the lowest part of the downhole tubing string, all threads are tightened, and the tool is lowered into the well. When the lowering device is 1-2 meters from the top of the fish, the lowering is stopped, and the total suspended weight is recorded. Then, the mud pump is turned on to flush the fish. After the fish is cleaned, the mud pump is turned off, and the fishing tool is slowly lowered again. When the suspended weight drops, the lowering is stopped, and the drill string is attempted to be lifted. Once the fish is confirmed to be caught, the device is lifted, and the fish is retrieved. If the fish gets stuck while being retrieved, lower the tool string until the weight indicator drops below the suspended weight, then stop lowering, turn on the mud pump for about 10 seconds, and then pull up the tool string to remove the fish. However, the structure of this tool differs from that of the tool described in this application. Summary of the Invention

[0004] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a hydraulically controlled, automatically reset internal retrieval tool with a reasonable structure that allows for manual lifting of the tubing string without pressure. Another objective of this invention is to provide a simple, easy-to-use, and highly efficient retrieval method.

[0005] To achieve the above objectives, the present invention provides a hydraulically controlled, automatically reset internal retrieval tool. The retrieval tool may include a fixed connection mechanism and a movable locking mechanism. The movable locking mechanism is capable of moving up and down relative to the fixed connection mechanism. The fixed connection mechanism includes an upper connector, a connecting shaft, a throttling sleeve, and a mandrel, coaxially connected from top to bottom. An adjusting ring is fitted onto the lower part of the upper connector. The adjusting ring can be freely engaged or disengaged. When engaged, the lower end face of the adjusting ring is flush with the lower end face of the upper connector. When disengaged, the lower end face of the adjusting ring moves out of the lower end face of the upper connector, and the adjusting ring presses against the reset piston to reset the movable locking mechanism. A reset piston passage hole and a release piston passage hole are radially arranged on the throttling sleeve. The reset piston passage hole is located above the release piston passage hole, and the two passage holes are spaced at a predetermined interval. The distance; a first stepped surface is provided on the circumferential outer surface of the spindle, and the first stepped surface fits against the lower end of the locking claw; the movable locking mechanism includes a reset piston, a release piston, a damping ring, a spring, and a locking claw; the reset piston is located on the upper circumferential outer surface of the throttling sleeve and is in sealed contact with the connecting shaft and the throttling sleeve; a reset piston cavity is formed between the reset piston, the connecting shaft, and the throttling sleeve; the liquid passage hole of the reset piston communicates with the reset piston cavity; the release piston is located on the lower circumferential outer surface of the throttling sleeve and is connected to the reset piston; a release piston cavity is formed between the release piston and the throttling sleeve; the liquid passage hole of the release piston communicates with the release piston cavity; the piston area of ​​the release piston cavity is larger than the piston area of ​​the reset piston cavity; the damping ring is disposed between the reset piston and the release piston, and it is locked to the throttling sleeve when not subjected to external force; the spring is disposed at the lower end of the release piston, and the locking claw is connected to the spring.

[0006] According to one or more exemplary embodiments of one aspect of the present invention, a throttling reduction can be provided in the inner cavity of the throttling sleeve, and during large-displacement pumping, the pressure at the lower end of the throttling reduction is lower than the pressure at its upper end.

[0007] According to one or more exemplary embodiments of one aspect of the present invention, a serrated snap may be provided between the damping ring and the throttling sleeve.

[0008] According to one or more exemplary embodiments of one aspect of the present invention, a fixing ring may be fitted on the outer circumferential surface of the mandrel. The fixing ring is located at the lower end of the spring and connected to the locking claw. After the locking claw leaves the first step surface, it can rotate with the fixing ring as the fulcrum.

[0009] According to one or more exemplary embodiments of one aspect of the present invention, a skirt may be provided on the lower circumferential outer surface of the release piston, and a second stepped surface may be provided in the middle part of the locking claw, and the skirt may contact the second stepped surface.

[0010] According to one or more exemplary embodiments of one aspect of the present invention, the release piston may be connected to the skirt cover threaded connection.

[0011] According to one or more exemplary embodiments of one aspect of the present invention, a set screw may be provided between the release piston and the skirt sleeve.

[0012] According to one or more exemplary embodiments of one aspect of the present invention, a retaining ring may be provided on the lower circumferential outer surface of the mandrel.

[0013] According to one or more exemplary embodiments of one aspect of the present invention, an O-ring may be provided between the lower inner wall of the upper connector and the upper outer wall of the connecting shaft; an O-ring may be provided between the lower inner wall of the connecting shaft and the upper outer wall of the throttling sleeve; an O-ring may be provided between the lower outer wall of the connecting shaft and the upper inner wall of the reset piston; an O-ring may be provided between the lower inner wall of the reset piston and the upper outer wall of the throttling sleeve; an O-ring may be provided between the lower outer wall of the throttling sleeve and the inner wall of the release piston; an O-ring may be provided between the lower inner wall of the throttling sleeve and the upper outer wall of the mandrel; and an O-ring may be provided on the lower outer wall of the mandrel.

[0014] According to one or more exemplary embodiments of one aspect of the present invention, the upper inner wall of the upper connector may be provided with threads, which can be connected to the retrieval tubing; the upper connector is threadedly connected to the connecting shaft; the upper connector is threadedly connected to the adjusting ring; the connecting shaft is threadedly connected to the throttling sleeve; the throttling sleeve is threadedly connected to the mandrel; and the reset piston is threadedly connected to the release piston.

[0015] Another aspect of the present invention provides a retrieval method, which can be implemented using the hydraulically controlled, automatically resettable internal retrieval tool described above. The method may include the following steps: the hydraulically controlled, automatically resettable internal retrieval tool is connected to the lower end of the tubing string and is lowered into the well along with the tubing string; when the hydraulically controlled, automatically resettable internal retrieval tool is lowered to the upper end of the downhole tubing tool, the lowering speed of the tubing string is reduced, and the mandrel and locking claw enter the inner cavity of the downhole reconnection tool to complete the reconnection action between the hydraulically controlled, automatically resettable internal retrieval tool and the downhole tubing tool; the tubing string is then lifted to complete the retrieval.

[0016] According to one or more exemplary embodiments of another aspect of the present invention, if the retrieval is successful but the retrieval is stuck, liquid can be pumped into the interior of the hydraulically controlled, automatically resettable internal retrieval tool, the moving locking mechanism moves upward relative to the fixed connection mechanism, and the hydraulically controlled, automatically resettable internal retrieval tool is in a released state and separated from the downhole tubular tools.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0018] (1) The hydraulically controlled automatic reset internal retrieval tool proposed in this invention uses hydraulic control to unlock and reset the retrieval tool's locking claws, enabling the release action to be completed without pressure.

[0019] (2) Using the hydraulically controlled automatic reset internal fishing tool proposed in this invention for fishing can greatly reduce the resistance of the locking claws entering and exiting the downhole tubular tools.

[0020] (3) The salvage method proposed in this invention is simple and easy to implement. Attached Figure Description

[0021] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1 A schematic diagram of a hydraulically controlled, automatically resettable internal retrieval tool in a reconnected state, according to an exemplary embodiment of the present invention, is shown.

[0023] Figure 2 This diagram illustrates a structural schematic of the reconnection process between a hydraulically controlled, automatically resettable internal retrieval tool and a downhole tubular tool, representing an exemplary embodiment of the present invention.

[0024] Figure 3 This diagram illustrates a structural schematic of a hydraulically controlled, automatically resettable internal retrieval tool reconnected to a downhole tubular tool, according to an exemplary embodiment of the present invention.

[0025] Figure 4 A schematic diagram of a hydraulically controlled, automatically resettable internal retrieval tool in a released state, according to an exemplary embodiment of the present invention, is shown.

[0026] Figure label:

[0027] 1-Upper connector, 2-Connecting shaft, 3-Adjusting ring, 4-Throttle sleeve, 41-Reset piston through hole, 42-Release piston through hole, 5-Mandrel, 6-Reset piston, 7-Release piston, 8-Damping ring, 9-Spring, 10-Locking claw, 11-Fixing ring, 12-Skirt sleeve, 13-Setting screw, 14-Retaining ring. Detailed Implementation

[0028] In the following description, a hydraulically controlled, automatically reset internal retrieval tool and retrieval method of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0029] In the description of this application, it should be understood that the terms "middle", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] The terms "first," "second," "third," etc., are used merely for convenience of description and distinction, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Exemplary Example 1

[0033] This exemplary embodiment provides a hydraulically controlled, automatically resettable internal retrieval tool.

[0034] Figure 1 A schematic diagram of a hydraulically controlled, automatically resettable internal retrieval tool in a reconnected state, according to an exemplary embodiment of the present invention, is shown. Figure 2 This diagram illustrates a structural schematic of the reconnection process between a hydraulically controlled, automatically resettable internal retrieval tool and a downhole tubular tool, representing an exemplary embodiment of the present invention. Figure 3 This diagram illustrates a structural schematic of a hydraulically controlled, automatically resettable internal retrieval tool reconnected to a downhole tubular tool, according to an exemplary embodiment of the present invention. Figure 4 A schematic diagram of a hydraulically controlled, automatically resettable internal retrieval tool in a released state, according to an exemplary embodiment of the present invention, is shown below. Figures 1 to 4 This describes a hydraulically controlled, automatically resettable internal retrieval tool in an exemplary embodiment. It should be noted that the top-to-bottom direction described in the specification is... Figures 1 to 4 The direction from left to right in the middle.

[0035] like Figure 1 As shown, the hydraulically controlled automatic reset internal retrieval tool (hereinafter referred to as the retrieval tool) mainly includes a fixed connection mechanism and a movable locking mechanism. The movable locking mechanism can move up and down relative to the fixed connection mechanism.

[0036] The fixed connection mechanism includes, from top to bottom, an upper connector 1, a connecting shaft 2, a throttling sleeve 4, and a spindle 5, all coaxially connected. An adjusting ring 3 is fitted onto the lower part of the upper connector 1. The adjusting ring can be freely engaged or disengaged. When engaged, the lower end face of the adjusting ring is flush with the lower end face of the upper connector, without affecting the retraction and release of the retrieval tool. When disengaged, the lower end face of the adjusting ring moves out of the lower end face of the upper connector, and the adjusting ring presses against the reset piston, forcing the movement locking mechanism of the retrieval tool to reset. The throttling sleeve 4 has two rows of liquid passage holes radially arranged. The upper row of liquid passage holes is the reset piston liquid passage hole 41, and the lower row is the release piston liquid passage hole 42. The reset piston liquid passage hole 41 is located above the release piston liquid passage hole 42, and there is a predetermined distance between the reset piston liquid passage hole 41 and the release piston liquid passage hole 42. A first stepped surface is provided on the outer circumference of the mandrel 5. Under the action of spring force, the lower end of the locking claw 10 can fit against the first stepped surface of the mandrel 5, providing internal support for the locking claw and restricting its radial retraction. After the locking claw fits against the stepped surface of the mandrel, it can restrict the inward retraction of the locking claw, thus locking the locking claw in the inner groove of the downhole tubular tool, ensuring a reliable connection between the locking claw and the required fishing tool. A locking structure is formed between the locking claw 10 and the first stepped surface of the mandrel 5. After the fishing tool enters the downhole tubular tool, the locking claw 10 fits against the first stepped surface under the action of spring force, forcing the locking claw to prevent it from retracting. The inward retraction of the locking claw means that, without internal constraint, the locking claw can rotate around the contact point between the locking claw and the mandrel as a fulcrum. The result of the rotation is that the end of the locking claw can retract inward. After retraction, the overall outer diameter of the end of the locking claw becomes smaller, ensuring that the locking claw is always in a locked state. During the fishing operation, the mandrel can be moved downward and inserted into the downhole tubular tool to seal it.

[0037] The movable locking mechanism includes: a reset piston 6, a release piston 7, a damping ring 8, a spring 9, and a locking claw 10. The reset piston 6 is located on the upper circumferential outer surface of the throttling sleeve 4 and is in sealed contact with the connecting shaft 2 and the throttling sleeve 4. Under hydraulic pressure, the reset piston 6 can move relative to the connecting shaft 2 and the throttling sleeve 4. A reset piston cavity is formed between the reset piston 6, the connecting shaft 2, and the throttling sleeve 4, and the reset piston's liquid passage hole communicates with the reset piston cavity. The release piston 7 is located on the lower circumferential outer surface of the throttling sleeve 4 and is connected to the reset piston 6. A release piston cavity is formed between the release piston 7 and the throttling sleeve 4, and the release piston's liquid passage hole communicates with the release piston cavity. The piston area of ​​the release piston cavity is larger than that of the reset piston cavity. The damping ring can provide axial limiting, ensuring that the entire external structure of the retrieval tool (referring to the movable locking mechanism) remains in the released state after pressure relief. A damping ring 8 is positioned between the reset piston 6 and the release piston 7. The upper end of the damping ring 8 contacts the lower end of the reset piston 6, and the lower end of the damping ring 8 contacts the upper end of the release piston 7. A serrated connection can be provided between the damping ring 8 and the throttling sleeve 4, ensuring that the damping ring 8 and the throttling sleeve 4 are locked together when no external force is applied. The damping force between the damping ring and the throttling sleeve is greater than the spring's compression force, ensuring that the fishing tool can be reconnected to downhole casing tools when in the reconnection state. The spring is located at the lower end of the release piston, and the locking pawl is connected to / in contact with the spring. When the spring is compressed, it always provides an axial thrust to the locking pawl, forcing the locking pawl to engage with the mandrel's stepped surface.

[0038] After the retrieval tool enters the downhole tubular tool, pumping fluid into the tubing causes the damping ring and locking claw to move upwards as a whole. After depressurization, the damping ring locks with the throttling sleeve, keeping the retrieval tool's movement locking mechanism in an upward position. The locking claw is disengaged from the first step surface of the mandrel, allowing the retrieval tool to be lifted and released without pressure. After the retrieval tool is released, pressurizing the tubing automatically resets the movement locking mechanism.

[0039] In this exemplary embodiment, a throttling reduction can be provided in the inner cavity of the throttling sleeve. During high-volume pumping, under the throttling reduction of the throttling sleeve, the pressure at the lower end of the throttling reduction is lower than the pressure at the upper end. At this time, the pressure at the lower end is lower than the pressure at the upper end, but the piston area of ​​the release piston chamber at the lower end is larger than the piston area of ​​the reset piston chamber at the upper end. The force acting on the release piston is to the left, and the force on the reset piston is to the right, ensuring that the pressure at the lower end of the throttling reduction is much lower than the pressure at the upper end. This ensures that the force on the reset piston is greater than the force on the release piston, pushing the entire moving locking mechanism to move to the right, and the entire moving locking mechanism resets.

[0040] In this exemplary embodiment, as Figure 1 As shown, a skirt 12 may be provided on the lower circumferential outer surface of the release piston 7, and the two are connected by threads. A set screw 13 may be provided between the two to prevent the release piston 7 from separating from the skirt 12.

[0041] In this exemplary embodiment, as Figure 1 As shown, a spring 9, a retaining ring 11, and a locking pawl 10 can be sequentially arranged between the release piston 7 and the skirt sleeve 12. The retaining ring 11 is sleeved on the outside of the spindle 5 and can move up and down along the spindle. The retaining ring is a connecting part between the spring and the locking pawl, and its function is to transmit the spring force to the locking pawl. The skirt sleeve 12 is set on the outside of the locking pawl 10 to prevent the locking pawl from falling off. The locking pawl and the retaining ring can form a lever structure. The upper end of the locking pawl 10 contacts the lower end of the retaining ring 11 (end face contact). After the locking pawl is separated from the step surface of the spindle, it can rotate at a small angle around its own support point. That is, after the locking pawl 10 is separated from the first step surface of the spindle 5, it can rotate with the retaining ring 11 as the fulcrum. Specifically, it can rotate with the contact point between the locking pawl and the spindle as the fulcrum. The rotation angle is such that the lower end of the locking pawl contacts the outer diameter of the spindle, and the locking pawl 10 can retract inward. The middle part of the locking pawl 10 is provided with a second step surface that can contact / fit with the skirt sleeve 12. After the entire moving locking mechanism moves upward, the end of the skirt contacts the raised step surface in the middle of the locking claw, keeping the locking claw under the action of spring force at all times. Here, the locking claw can be a split structure, and the skirt can fit the locking claw on the spindle, which limits the locking claw and prevents it from falling off.

[0042] In this exemplary embodiment, as Figure 1 As shown, a retaining ring 14 can be provided on the lower circumferential outer surface of the mandrel 5. Here, two retaining rings can be provided at the lower end of the mandrel. An O-ring can be provided on the lower outer wall of the mandrel. Specifically, a sealing groove can be provided at the lower end of the mandrel, and the sealing groove can be provided with a sealing structure of O-ring + retaining ring.

[0043] In this exemplary embodiment, an O-ring seal may be provided between the lower inner wall of the upper connector and the upper outer wall of the connecting shaft. An O-ring seal may be provided between the lower inner wall of the connecting shaft and the upper outer wall of the throttling sleeve. An O-ring seal may be provided between the lower outer wall of the connecting shaft and the upper inner wall of the reset piston. An O-ring seal may be provided between the lower inner wall of the reset piston and the upper outer wall of the throttling sleeve. An O-ring seal may be provided between the lower outer wall of the throttling sleeve and the inner wall of the release piston. Here, the circumferential outer surface of the throttling sleeve is provided with a third stepped surface, which may have two steps. O-ring seals may be provided between the inner wall of the release piston and the two stepped surfaces of the throttling sleeve, respectively. An O-ring seal may be provided between the lower inner wall of the throttling sleeve and the upper outer wall of the mandrel.

[0044] In this exemplary embodiment, the upper inner wall of the upper connector may be provided with threads, enabling connection to the retrieval tubing. The upper connector is threadedly connected to the connecting shaft. The upper connector is threadedly connected to the adjusting ring. The connecting shaft is threadedly connected to the throttling sleeve. The throttling sleeve is threadedly connected to the mandrel. The reset piston is threadedly connected to the release piston.

[0045] The method / operation process of using the hydraulically controlled, automatically resetting internal retrieval tool of the present invention includes:

[0046] The retrieval operation employs a hydraulically controlled, automatically resetting internal retrieval tool. First, the retrieval tool is lowered to connect with downhole tubing tools. At this point, the corresponding... Figure 2 The diagram illustrates the state of the hydraulically controlled, automatically reset internal fishing tool reconnection process with the downhole tubing. Continue lowering until the fishing tool is successfully connected to the downhole tubing; at this point, the corresponding... Figure 3 The diagram shows the state of the hydraulically controlled, automatically reset internal fishing tool when reconnected to the downhole tubing tool. After successful connection, the tool is lifted to separate it from the downhole tubing tool. Figure 4 The hydraulically controlled, automatically reset internal retrieval tool shown is in the released state. After the retrieval tool separates from the downhole tubing, it is reset to its initial state for future use. Figure 1 The hydraulically controlled, automatically resettable internal retrieval tool shown is in the reconnected state. That is, during retrieval operations using the hydraulically controlled, automatically resettable internal retrieval tool, the tool can mainly perform three actions: reconnection to downhole tubing tools, release, and reset. These three processes are described below.

[0047] Reconnection of the retrieval tool to the downhole tubing tool: The retrieval tool is connected to the lower end of the tubing string and is lowered into the well along with the tubing string. When the retrieval tool is lowered to the upper end of the downhole reconnection tool (i.e., the downhole tubing tool), the lowering speed of the tubing string is reduced, and the mandrel enters the inner cavity of the downhole reconnection tool. The outer diameter of the locking claw is larger than the inner diameter of the downhole reconnection tool, while the mandrel is smaller than the inner diameter of the downhole reconnection tool. The mandrel enters the inner cavity of the downhole reconnection tool, and the locking claw is restricted to the outside by the end face of the downhole reconnection tool, separating from the stepped surface of the mandrel. After the locking claw separates from the stepped surface of the mandrel, the locking claw can rotate at a small angle along the protruding position of the locking claw under the pressure of the end face, and the outer diameter of the locking claw end contracts. When the outer diameter of the locking claw after contraction is smaller than the inner diameter of the reconnection tool, the locking claw enters the interior of the reconnection tool, and the locking claw is released from the restraint of the end of the reconnection tool. Under the action of spring force, the locking claw continues to descend until it locks and fits against the stepped surface of the mandrel, completing the reconnection operation between the retrieval tool and the downhole reconnection tool.

[0048] Release of the retrieval tool: With the retrieval tool and downhole tubing tools in the reconnected state, fluid is pumped into the retrieval tool. The fluid enters the reset piston chamber and the release piston chamber through the reset piston inlet and the release piston inlet, respectively. The hydraulic force area of ​​the reset piston chamber is smaller than that of the release piston chamber, and the force of the reset piston is less than that of the release piston. The release piston drives the retrieval tool's reset piston, damping ring, spring, retaining ring, skirt, and locking claw to move upward as a whole. The locking claw disengages from the stepped surface of the mandrel, and the locking claw is in a retrievable state. The damping ring and the throttling sleeve are connected by a serrated thread. After the internal pressure of the fishing tool is depressurized, the damping ring is locked in place by the serrated thread between it and the throttling sleeve. The locking of the damping ring can keep the reset piston, release piston, spring, fixing ring, skirt and locking claw on the outside of the fishing tool in an upward locked state after the internal pressure of the fishing tool is depressurized. The locking claw lifts the fishing tool, and the downhole tubing tool forces the locking claw to retract inward. The fishing tool can be separated from the downhole tubing tool.

[0049] Reset of the retrieval tool: After the retrieval tool is released from the downhole tubing, the reset piston, damping ring, release piston, spring, retaining ring, skirt, and locking claw on the outside of the retrieval tool remain in an upward-locked state, with the damping ring locked to the throttling sleeve by a serrated interlock. While the retrieval tool is in the released state, a large-volume pump injects fluid into the retrieval tool, creating a throttling effect inside the throttling sleeve. This results in a pressure at the inlet of the reset piston being significantly higher than that at the inlet of the release piston. The force generated by the reset piston is greater than that generated by the release piston, hydraulically pushing the reset piston downwards. The reset piston then pushes the damping ring, release piston, spring, retaining ring, skirt, and locking claw on the outside of the retrieval tool downwards, restoring the retrieval tool to its initial state. The locking claw engages with the stepped surface of the mandrel, and the retrieval tool is reset.

[0050] Exemplary Example 2

[0051] This exemplary embodiment provides a salvage method.

[0052] The salvage method of this exemplary embodiment can be implemented by the hydraulically controlled, automatically resettable internal salvage tool described in Exemplary Embodiment 1 above.

[0053] The retrieval method may include the following steps: A hydraulically controlled, automatically resettable internal retrieval tool is connected to the lower end of the tubing string and lowered into the well along with the tubing string. Once the hydraulically controlled, automatically resettable internal retrieval tool is lowered to the upper end of the downhole tubing tool, the lowering speed of the tubing string is reduced, and the mandrel and locking claws enter the inner cavity of the downhole reconnection tool, completing the reconnection action between the hydraulically controlled, automatically resettable internal retrieval tool and the downhole tubing tool. The tubing string is then pulled back, completing the retrieval process.

[0054] In this exemplary embodiment, if the hydraulically controlled self-resetting internal retrieval tool and the downhole re-connection tool are successfully retrieved, and the downhole re-connection tool encounters jamming again in the well during the process of the retrieval tool pulling the downhole re-connection tool upwards, then liquid can be pumped into the hydraulically controlled self-resetting internal retrieval tool, the moving locking mechanism moves upwards relative to the fixed connection mechanism, and the hydraulically controlled self-resetting internal retrieval tool is in a released state, separating from the downhole tubular tools.

[0055] In summary, the advantages proposed by this invention include at least one of the following:

[0056] (1) The hydraulically controlled automatic reset internal retrieval tool proposed in this invention is safe and reliable for reconnecting downhole pipe tools.

[0057] (2) In a single drilling operation, the hydraulically controlled automatic resetting internal retrieval tool proposed in this invention can be used to perform multiple repeated dropping and re-retrieval operations, which greatly reduces operating costs and improves work efficiency.

[0058] (3) The salvage method proposed in this invention can greatly reduce the resistance when entering and exiting downhole tubular tools.

[0059] Although a hydraulically controlled, automatically reset internal retrieval tool and retrieval method of the present invention have been described above in conjunction with exemplary embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A hydraulically controlled, automatically resetting internal retrieval tool, characterized in that, The salvage tool includes a fixed connecting mechanism and a movable locking mechanism. The movable locking mechanism can move up and down relative to the fixed connecting mechanism. The fixed connection mechanism includes an upper connector, a connecting shaft, a throttling sleeve, and a spindle, which are coaxially connected from top to bottom. An adjusting ring is fitted on the lower part of the upper connector. The adjusting ring can be freely engaged or disengaged. When engaged, the lower end face of the adjusting ring is flush with the lower end face of the upper connector. When disengaged, the lower end face of the adjusting ring moves out of the lower end face of the upper connector, and the adjusting ring presses the reset piston to reset the moving locking mechanism. The throttling sleeve is provided with a reset piston liquid passage hole and a release piston liquid passage hole in the radial direction. The reset piston liquid passage hole is located above the release piston liquid passage hole, and the reset piston liquid passage hole and the release piston liquid passage hole are spaced apart by a predetermined distance. A first stepped surface is provided on the outer circumferential surface of the spindle, and the first stepped surface is in contact with the lower end of the locking claw. The movable locking mechanism includes a reset piston, a release piston, a damping ring, a spring, and a locking claw; The reset piston is located on the upper circumferential outer surface of the throttling sleeve and is in sealed contact with the connecting shaft and the throttling sleeve; a reset piston cavity is formed between the reset piston, the connecting shaft and the throttling sleeve; the liquid passage hole of the reset piston is connected to the reset piston cavity; The release piston is located on the lower circumferential outer surface of the throttling sleeve and is connected to the reset piston; a release piston cavity is formed between the release piston and the throttling sleeve; the liquid passage of the release piston is connected to the release piston cavity; the piston area of ​​the release piston cavity is larger than the piston area of ​​the reset piston cavity. The damping ring is positioned between the reset piston and the release piston, and it is locked to the throttling sleeve when no external force is applied. The spring is located at the lower end of the release piston, and the locking pawl is connected to the spring.

2. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, The throttling sleeve has a throttling reducer inside, so that when pumping at a large displacement, the pressure at the lower end of the throttling reducer is lower than the pressure at the upper end.

3. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, A serrated snap is provided between the damping ring and the throttling sleeve.

4. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, A fixing ring is fitted on the outer circumferential surface of the mandrel. The fixing ring is located at the lower end of the spring and is connected to the locking claw. After the locking claw leaves the first step surface, it can rotate around the fixing ring as a fulcrum.

5. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, A skirt is provided on the lower circumferential outer surface of the release piston, and a second step surface is provided in the middle part of the locking claw, with the skirt in contact with the second step surface.

6. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 5, characterized in that, The release piston is connected to the skirt cover via a threaded connection.

7. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 5 or 6, characterized in that, A set screw is provided between the release piston and the skirt cover.

8. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, A retaining ring is provided on the lower circumferential outer surface of the mandrel.

9. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, An O-ring is provided between the lower inner wall of the upper connector and the upper outer wall of the connecting shaft. An O-ring is provided between the lower inner wall of the connecting shaft and the upper outer wall of the throttling sleeve; An O-ring is provided between the lower outer wall of the connecting shaft and the upper inner wall of the reset piston; An O-ring is provided between the lower inner wall of the reset piston and the upper outer wall of the throttling sleeve; An O-ring is provided between the lower outer wall of the throttling sleeve and the inner wall of the release piston; An O-ring is provided between the lower inner wall of the throttling sleeve and the upper outer wall of the mandrel; An O-ring is provided on the lower outer wall of the mandrel.

10. The hydraulically controlled, automatically resetting internal retrieval tool according to claim 1, characterized in that, The upper inner wall of the upper connector is provided with threads, which can be connected to the salvage tubing; The upper connector is threadedly connected to the connecting shaft; The upper connector is threadedly connected to the adjusting ring. The connecting shaft is connected to the throttling sleeve thread; The throttling sleeve is threadedly connected to the mandrel. The reset piston is threadedly connected to the release piston.

11. A salvage method, characterized in that, The salvage method is implemented using a hydraulically controlled, automatically resettable internal salvage tool as described in any one of claims 1 to 10. The method includes the following steps: The hydraulically controlled, automatically reset internal retrieval tool is connected to the lower end of the tubing string and is lowered into the well along with the tubing string. When the hydraulically controlled automatic reset internal fishing tool is lowered to the upper end of the downhole tubular tool, the lowering speed of the tubing string is reduced, and the mandrel and locking claws enter the inner cavity of the downhole reconnection tool to complete the reconnection action between the hydraulically controlled automatic reset internal fishing tool and the downhole tubular tool. Raise the tubing string to complete the retrieval.

12. The salvage method according to claim 11, characterized in that, If the retrieval is successful but the retrieval tool gets stuck, liquid is pumped into the hydraulically controlled, automatically reset internal retrieval tool. The moving locking mechanism moves upward relative to the fixed connection mechanism, and the hydraulically controlled, automatically reset internal retrieval tool is released from the downhole tubular tool.

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