Releasable slip fisher and fishing method

Abstract

The invention provides a releasable slip fisher and a fishing method. The releasable slip fisher comprises an upper connector, a connecting cylinder is connected to the upper connector, a groove is formed in one side of the connecting cylinder, an unlocking spring is placed in the groove, a mandrel is arranged in the connecting cylinder, a pressing cap is arranged at the top of the mandrel, and the top of the pressing cap is supported at the bottom of the upper connector. The bottom of the pressing cap compresses the unlocking spring and the mandrel at the same time, a groove is formed in the other side of the connecting cylinder, a working spring is placed in the groove, the bottom of the mandrel is connected with a slip bowl, the top of the slip bowl is supported by the working spring, the bottom of the slip bowl is provided with a slip groove, a slip is arranged in the slip groove, and the lower portion of the connecting cylinder is in threaded connection with a fishing cylinder. Open holes are formed in the connecting cylinder and the core shaft, the connecting cylinder and the core shaft are connected through shear pins, the fishing tool can be used for fishing tools without outer fishing diameters (such as smooth cylindrical parts), the limitation that a conventional fishing tool needs to be matched with an underground fished object in standard size is avoided, and the fishing range is wide.

Description

Technical Field

[0001] The invention belongs to the field of well logging and salvaging, and in particular relates to a releasable slip salvage device and a salvaging method. Background Art

[0002] In order to evaluate the reservoir seepage capacity and stable production capacity of oil and gas wells, a drop-and-drop pressure gauge is usually used to conduct well testing.

[0003] However, in high-sulfur and high-carbon dioxide gas wells, downhole test tools are exposed to the flowback fluid, high-sulfur and high-carbon dioxide environments for a long time, which will cause varying degrees of corrosion or scaling, making it impossible to remove the downhole test tools with conventional salvage tools. Conventional slip salvage tools are used for salvage. Since the slip salvage tool jacket generally adopts a closed structure, the distance between the slip and the jacket is fixed, and the working radius of the slip is limited. If heavy oil, sand and other materials in the well enter the space between the slip and the jacket, the two slips will be misaligned and asynchronous in upward or downward movement, resulting in a low salvage success rate. Summary of the invention

[0004] The present invention provides a releasable slip salvage device and a salvage method, which solves the problem of salvage failure caused by corrosion and scaling of the salvaged device.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A releasable slip salvage device comprises an upper joint, the upper joint is connected to a connecting tube, one side of the connecting tube is provided with a groove, an unlocking spring is placed in the groove, a core shaft is arranged in the connecting tube, a pressure cap is arranged on the top of the core shaft, the top of the pressure cap is supported on the bottom of the upper joint, and the bottom of the pressure cap compresses the unlocking spring and the core shaft at the same time, the other side of the connecting tube is also provided with a groove, a working spring is placed in the groove, the bottom of the core shaft is connected to a slip seat, the top of the slip seat is supported on the working spring, the bottom is provided with a slip groove, a slip is arranged in the slip groove, a salvage tube is threadedly connected to the lower part of the connecting tube, openings are arranged in the connecting tube and the core shaft, and are connected by a shear pin.

[0007] Preferably, the free end of the upper connector is connected to an external tool string.

[0008] Preferably, the upper joint is connected to the tool string and the connecting tube by bolt connection.

[0009] Preferably, the mandrel is arranged at the center of the connecting cylinder.

[0010] Preferably, the openings of the connecting tube and the core shaft are both opened in the middle.

[0011] Preferably, the canister is an inverted cone-shaped structure.

[0012] Preferably, a step is provided at the bottom of the core shaft, and the slip seat is provided on the step.

[0013] Preferably, the slips are six slip tiles evenly distributed, with gaps between the six slip tiles.

[0014] Preferably, the cava piece is provided with teeth.

[0015] A releasable slip salvage method is based on a releasable slip salvage device. The salvage device is connected to a tool string, lowered into a well along with the tool string, and the lowering tension and speed are recorded. When the tool string is lowered to the location of the fallen object in the well, the lowering is stopped, the tool string is lifted up for a distance, and the tool string is vibrated downward so that the slip enters the fallen object in the well and bites it firmly. The tool string is gradually lifted up, and the tension change is observed. If the lifting tension is similar to the tension when lowering, it means that the slip does not bite the fallen object in the well and needs to be lifted up to the location of the fallen object in the well. Repeat the salvage above. If the upward tension gradually increases, it proves that the salvage device has captured the fallen objects in the well. At this time, you can gradually apply pulling force to lift the downhole device to complete the salvage. If the upward tension continues to rise and approaches the limit of the steel wire and the fallen objects in the well are still not loose, you can use the jar installed in advance to use the upward shock force to lift the fallen objects in the well. If the fallen objects in the well cannot be lifted out by shocking, you can use a strong downward shock to cut the shear pin. After the shear pin is cut off, the slip withdraws from the fallen objects in the well to complete the removal, and finally lift out the tool string.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a releasable slip salvage device, which is a tool that can be used for salvaging without an external salvage diameter. When in use, connect the salvage device to the tool string, lower it into the well along with the tool string, and record the lowering tension and speed. When the tool string reaches the place where the object is dropped in the well, stop lowering it, lift the tool string for a distance, and shock it downwards so that the slips enter the object and bite it firmly. Then gradually lift the tool string and observe the tension change. If the lifting tension is similar to the tension when lowering it, it means that the slips do not bite the object in the well and it needs to be lifted up to the object and repeated salvage. If the lifting tension gradually increases, it proves that the salvage device has captured the object in the well. At this time, you can gradually apply pulling force to lift out the downhole device to complete the salvage. If the lifting tension continues to rise and approaches the limit of the steel wire and the object in the well is still not loose, you can use the jar installed in advance to use the upward shock force to lift out the object in the well. If the object in the well cannot be lifted out by shocking, you can shock it downwards strongly to cut the shear pin. After the shear pin is cut off, the slips withdraw from the object in the well to complete the removal, and finally pull out the tool string. The problem of salvage failure caused by corrosion and scaling of salvage equipment in the well during salvage operations of high-sulfur and high-carbon dioxide gas wells is solved.

[0017] Furthermore, the tool can be used for salvaging without an external salvage diameter, is not subject to the restriction that conventional salvage tools need to match the standard size of the salvaged objects in the well, and has a wide salvage range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a releasable slip salvage device of the present invention;

[0019] Figure 2 A schematic diagram of a salvaging method of a releasable slip salvage device according to the present invention;

[0020] In the figure, 1-upper joint; 2-pressure cap; 3-unlocking spring; 4-connecting tube; 5-shear pin; 6-core shaft; 7-working spring; 8-cava seat; 9-bailing tube; 10-cava. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the present invention provides a releasable slip salvage device, comprising an upper joint 1, the upper joint 1 is connected to a connecting tube 4, one side of the connecting tube 4 is provided with a groove, an unlocking spring 3 is placed in the groove, a core shaft 6 is arranged in the connecting tube 4, a pressure cap 2 is arranged on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, the other side of the connecting tube 4 is also provided with a groove, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided at the bottom, a slip is arranged in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and openings are arranged in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0029] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0030] The free end of the upper connector 1 is connected to an external tool string.

[0031] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0032] The upper joint 1 is connected to the tool string and the connecting tube 4 by bolt connection.

[0033] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0034] The core shaft 6 is arranged at the center of the connecting cylinder 4 .

[0035] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0036] The openings of the connecting tube 4 and the core shaft 6 are both opened in the middle.

[0037] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0038] The bailing tube 9 is an inverted cone structure.

[0039] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0040] A step is arranged at the bottom of the core shaft 6, and the slip seat 8 is arranged on the step.

[0041] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0042] The slips 10 are six slip tiles evenly distributed, with gaps between the six slip tiles.

[0043] Another embodiment of the present invention provides a releasable slip salvage device, including an upper joint 1, to which a connecting tube 4 is connected, a groove is provided on one side of the connecting tube 4, an unlocking spring 3 is placed in the groove, a core shaft 6 is provided in the connecting tube 4, a pressure cap 2 is provided on the top of the core shaft 6, the top of the pressure cap 2 is supported on the bottom of the upper joint 1, and the bottom of the pressure cap 2 compresses the unlocking spring 3 and the core shaft 6 at the same time, a groove is also provided on the other side of the connecting tube 4, a working spring 7 is placed in the groove, a slip seat 8 is connected to the bottom of the core shaft 6, the top of the slip seat 8 is supported on the working spring 7, a slip groove is provided on the bottom, a slip is provided in the slip groove, a salvage tube 9 is threadedly connected to the lower part of the connecting tube 4, and an opening is provided in the connecting tube 4 and the core shaft 6, which are connected by a shear pin 5.

[0044] The slips 10 are six slips evenly distributed, with gaps between the six slips, and teeth are arranged on the slips.

[0045] Another embodiment of the present invention provides a releasable slip catching device, comprising an upper joint 1, a pressure cap 2, an unlocking spring 3, a connecting tube 4, a shear pin 5, a mandrel 6, a working spring 7, a slip seat 8, a bailing tube 9, and a slip 10. The upper end of the upper joint 1 is threadedly connected to the upper tool string, and the lower end is threadedly connected to the connecting tube 4. An upward groove is provided on the upper part of the connecting tube 4, and the unlocking spring 3 is placed in the groove. A mandrel 6 is provided at the center of the connecting tube 4, and a pressure cap 2 is provided on the top of the mandrel 6. The pressure cap 2 can compress the unlocking spring 3 under the support of the bottom of the upper joint 1; the mandrel 6 can move freely in the connecting tube 4 under normal conditions; an opening is provided in the middle of the connecting tube 4 and the mandrel 6, and is connected by a shear pin 5; a downward groove is provided in the lower part of the connecting tube 4, and a working spring 7 can be placed in the groove; the lower part of the connecting tube 4 is threadedly connected to the bailing tube 9, and the bailing tube 9 is an inverted "V" cone structure. An inverted "T"-shaped step is provided at the bottom of the mandrel 6, and a slip seat 8 is provided on it. The upper part of the slip seat 8 supports the working spring 7, and the lower part is provided with a slip groove, which can be connected with the slip 10. The slip 10 is a six-petal type distributed around a circle, with a slight gap between each other, which can achieve contraction and expansion; the inner claw of the slip 10 is provided with a track tooth, which can grasp the salvaged tool when the slip 10 contracts; when the slip 10 is at different parts of the canister, the inner wall of the canister 9 gives different thrusts to the slip 10, so that the slip 10 can be opened or tightened to different degrees at different positions.

[0046] The present invention also provides a salvaging method of a releasable slip salvage device:

[0047] When using the present invention to salvage objects in the well, first, according to the size of the objects in the well, select a corresponding size of the slip salvage tube. After determining the size of the releasable slip salvage device of the present invention, connect the upper basic tool string through the upper joint 1 and lower it into the well. When the releasable slip salvage device reaches the top of the object, it stops lowering and switches to a slight downward shock instead of a strong shock. At this time, the slip 10 is subjected to the upward force of the objects in the well and transmits the force to the working spring 7 through the slip seat 8. The working spring 7 begins to compress after being subjected to the upward force. At this time, the slip 10 and the salvage tube 9 produce relative motion, that is, upward motion. When the slip 10 rises to a wider position along the "V"-shaped salvage tube 9, the six-petal slip of the slip 10 opens naturally and enters the objects in the well. When the slip 10 enters the fallen objects in the well, the upward force given by the fallen objects in the well disappears, and the slip seat 8 only generates a downward thrust due to the release of the spring force of the working spring 7. The downward thrust causes the slip 10 to move downward along the inner wall of the bailing tube 9 into a narrower part. At this time, the six-petal slips of the slip 10 are tightened and bite to grasp the fallen objects in the well. After the grip is completed, the releasable slip salvage device can be lifted up. During the lifting process, the greater the gravity of the fallen objects in the well, the tighter the slip 10 contracts and the more firmly it bites. If the fallen objects in the well are stuck in the well, the releasable slip salvage device cannot be lifted up and taken out, and the salvage of the fallen objects fails. It can be released by strong downward shock. After a strong downward shock, the slip 10 continues to move after entering the downhole objects, and the downhole objects touch the "T"-shaped step at the bottom of the mandrel 6, transmitting the shock force to the mandrel 6; at this time, the mandrel 6 is subjected to an upward shock force, while the connecting tube 4 is subjected to a downward shock force, and the force difference between the two causes the shear pin 5 to be sheared by force; after the shear pin 5 is sheared off, the connecting tube 4 and the mandrel 6 produce relative movement, that is, the connecting tube 4 moves downward, and the mandrel 6 drives the slip seat 8 to drive the slip 10 to move upward to complete the release of the downhole objects. Due to the existence of the unlocking spring 3, the spring force of the unlocking spring 3 is released to drive the pressure cap 2 to move upward, and the pressure cap 2 drives the mandrel 6 to move upward, so that the mandrel 6 after the shear pin 5 is sheared off can drive the slip 10 to the upper part of the bailing tube, that is, the wider part, to achieve the release of the downhole objects by the slip, and always keep it out of hand.

[0048] The salvage method of the present invention comprises the following steps: 1. Connecting the releasable cava salvage device to the basic tool string weighting rod, jar, etc. First, connect the wire rope cap to the weighting rod and the jar, and then connect the releasable cava salvage device through the upper joint 1. 2. Lower the tool string into the well, and record the lowering speed and lowering tension during the process. When the cava salvage device is connected, lower the salvage tool string into the well, and record the lowering speed and lowering tension as required, so as to make a good tension comparison when lifting, so as to judge whether the fallen objects in the well have been successfully salvaged. 3. When lowering to the place where the fallen objects are located in the well, stop lowering. When the tool string is lowered close to the fallen objects, reduce the lowering speed, and stop lowering when it is lowered to the place where the fallen objects are located in the well. 4. Lift up a short distance, and jar downward slightly without strong jarring, so that the cava enters the fallen objects in the well and bites firmly. Slightly shock downward so that the slip can smoothly enter the downhole objects. Do not shock strongly to avoid breaking the shear pin. When the slip enters, it will be squeezed by the bailing tube and bite the downhole objects. 5. Try to lift up. If the pressure rises to a certain value and can be successfully brought out according to the weight of the downhole objects, it means that the salvage is successful. If the lifting tension is not much different from the pressure recorded during the lowering, it means that the salvage is not successful. It is necessary to repeat step 4 until the lifting tension rises and confirms the success of the salvage. If the downhole objects are stuck, the lifting tension continues to rise and approaches the limit value of the steel wire, and the pin needs to be cut off to get rid of it. The specific operation is to shock downward strongly to cut off the shear pin. After the pin is cut off, the unlocking spring drives the mandrel and the mandrel drives the slip to move upward. The slip exits the bailing tube and gradually opens, and the hand is released. 6. Lift the tool string to the wellhead. Whether the salvage is successful or lost after the salvage fails, the downhole tool string needs to be pulled out in time to avoid being stranded in the well for a long time and causing responsible situations. During this period, it is necessary to pay attention to the tension changes and compare them with the recorded lowering tension value to determine whether the fallen objects in the well have slipped.

[0049] If the salvage fails and the shear pin is used, or the slip needs to be replaced, the assembly steps are as follows: 1. Replace the new shear pin 5: clamp the connecting tube 4 on the vise, unscrew the upper joint 1 and the bailing tube 9 respectively; insert the plate file into the groove of the pressure cap 2, twist the file with the adjustable wrench, unscrew the pressure cap, and take out the working spring 3; remove the mandrel 6 and punch out the broken pin; install the mandrel 6 into the connecting tube 4 and insert the new shear pin; put the working spring 3 on the mandrel 6 and tighten the pressure cap 2; then connect the upper joint 1, bailing tube 9 and the connecting tube 4 respectively, and tighten them to complete the shear pin replacement. 2. Replace the slip: clamp the connecting tube 4 on the vise, unscrew the bailing tube 9; put two wrenches on the slip seat 8 and the slip 10 respectively, and unscrew the slip 10; replace the slip with the required specification; tighten the slip 10 and the slip seat 8; install and tighten the bailing tube 9 to complete the slip replacement.

[0050] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A releasable slip salvage device, characterized in that: The invention comprises an upper joint (1), wherein a connecting tube (4) is connected to the upper joint (1), a groove is provided on one side of the connecting tube (4), an unlocking spring (3) is placed in the groove, a core shaft (6) is arranged in the connecting tube (4), a pressure cap (2) is arranged on the top of the core shaft (6), the top of the pressure cap (2) is supported on the bottom of the upper joint (1), and the bottom of the pressure cap (2) simultaneously compresses the unlocking spring (3) and the core shaft (6), a groove is also provided on the other side of the connecting tube (4), a working spring (7) is placed in the groove, a slip seat (8) is connected to the bottom of the core shaft (6), the top of the slip seat (8) is supported on the working spring (7), a slip groove is provided on the bottom, a slip is arranged in the slip groove, a scoop (9) is threadedly connected to the lower part of the connecting tube (4), and openings are provided in the connecting tube (4) and the core shaft (6), and are connected by a shear pin (5).

2. A releasable slip salvage device according to claim 1, characterized in that: The free end of the upper joint (1) is connected to an external tool string.

3. A releasable slip salvage device according to claim 2, characterized in that: The upper joint (1) is connected to the tool string and the connecting tube (4) by bolt connection.

4. A releasable slip salvage device according to claim 1, characterized in that: The core shaft (6) is arranged at the center of the connecting cylinder (4).

5. A releasable slip salvage device according to claim 1, characterized in that: The openings of the connecting tube (4) and the core shaft (6) are both opened in the middle.

6. A releasable slip salvage device according to claim 1, characterized in that: The bailing tube (9) is an inverted cone-shaped structure.

7. A releasable slip salvage device according to claim 1, characterized in that: The bottom of the core shaft (6) is provided with a step, and the slip seat (8) is arranged on the step.

8. A releasable slip salvage device according to claim 1, characterized in that: The slips (10) are six slip pieces evenly distributed, with gaps between the six slip pieces.

9. A releasable slip salvage device according to claim 7, characterized in that: The slip sheet is provided with teeth.

10. A salvaging method for a releasable slip salvage device, based on a releasable slip salvage device according to any one of claims 1 to 9, characterized in that: Connect the salvage device to the tool string and lower it into the well along with the tool string. Record the lowering tension and speed. When the tool string reaches the object in the well, stop lowering it. Lift the tool string up a distance and shock it downwards so that the slips (10) enter the object and bite it firmly. Lift the tool string up gradually and observe the tension change. If the tension when lifting up is similar to the tension when lowering, it means that the slips do not bite the object in the well. It is necessary to lift it up to the object in the well and repeat the salvage. If the tension when lifting up gradually increases, This proves that the salvage device has captured the fallen objects in the well. At this time, a pulling force can be gradually applied to lift the downhole device to complete the salvage. If the upward pulling tension continues to rise and approaches the limit of the steel wire and the fallen objects in the well are still not loose, the pre-installed jar can be used to use the upward shock force to lift the fallen objects in the well. If the fallen objects in the well cannot be lifted out by shock, a strong shock can be applied downward to cut the shear pin (5). After the shear pin (5) is cut, the slip withdraws from the fallen objects in the well to complete the removal, and finally the tool string is lifted out.

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