Hydraulic seat seal type pressure seal double-buckle fishing spear and fishing method

Abstract

The present application belongs to the field of workover under pressure, and relates to a hydraulic seat sealing type sealing and stabbing fishing spear under pressure and a fishing method. The fishing spear part is a rod sleeve structure with an axial central channel, and comprises a upper joint and a centralizing sleeve in threaded connection. A spear rod is connected to the inner cavity of the upper joint in threaded connection, and an overshot is arranged in the annular space formed by the spear rod and the centralizing sleeve. The tool also comprises a plug part, which comprises at least a hydraulic seat sealing mechanism, a seat sealing self-locking mechanism and a hydraulic sealing mechanism. The hydraulic pressure is transmitted to the hydraulic seat sealing mechanism through the fishing spear part, to push the hydraulic sealing mechanism to compress the seal, and at the same time, to push the seat sealing self-locking mechanism to lock, so as to realize the seat sealing and maintain the self-locking of the seal. The tool can be reversed and fished, the overshot is rotated to the tight connection direction and then withdrawn, and the plug is lifted to unseal. The static and dynamic sealing performance is good, the rubber tube is expanded by pressing in the pipe string to block the inside of the pipe, and the rubber tube has a self-locking function after the seat sealing, so as to maintain the dynamic sealing performance of the rubber tube.

Description

Technical Field

[0001] This invention belongs to the field of well workover technology for oil and gas fields under pressure, specifically relating to a hydraulic seated type pressurized sealing snap-locking retrieval spear and retrieval method. Background Technology

[0002] Because the formation contains acidic corrosive media such as H2S and CO2, as well as highly mineralized formation water, it is prone to long-term electrochemical corrosion of varying degrees. In addition, factors such as downhole throttling, well temperature, and tubing stress have led to serious failures of the production tubing, including localized punctures, perforations, thinning of the wall due to corrosion, and breakage. Since the tubing that has broken off and fallen into the well cannot be sealed with wire rope plugs, conventional fishing tools cannot be used to retrieve the fish from the wellhead under pressurized conditions.

[0003] In some gas wells, the tubing fell into the well and became necked or bent, making it impossible to seal the original well string with wire rope plugs. Under pressurized conditions, conventional retrieval tools could not retrieve the fallen tubing from the wellhead.

[0004] During live drilling operations at gas wells, due to the inability of the lower tools of the tubing string to be effectively sealed and the limitation of the internal height of the device, some downhole tools and supporting tools attached to the production tubing string of gas wells need to be cut or reversed inside the live drilling device. Conventional fishing tools cannot retrieve the fish that have been cut or reversed from the wellhead.

[0005] Under pressurized conditions at oil and gas wells, conventional fishing tools are used to retrieve broken tubing into the wellhead safety device. However, because these tools are not sealed, the fish (the part that holds the tubing) cannot be retrieved from the wellhead. The options are: either secure the fish to the blowout preventer (BOP) slips and withdraw the tool, install a tubing bridge plug, and then retrieve the drill string; or secure the fish to the BOP slips, cut off the upper part of the fish head, lower a conventional fishing tool with an internal plug to retrieve the fish head, then raise the fishing string above the full seal gate, release the pressure from the full seal gate to the annular seal or working gate, and then retrieve the fish head.

[0006] Currently, the main sealing tools for tubing blockages use wireline dropping and wireline lifting for vibration sealing, but these methods cannot seal tubing that has broken off inside the well, or deformed and perforated tubing. Using water plugs and well-killing methods to reduce wellhead pressure before retrieval operations can easily cause secondary damage to the formation, affecting oil and gas well productivity. Therefore, conventional well workover procedures for live retrieval operations are time-consuming, labor-intensive, and complex, and even slight mistakes can lead to downhole safety accidents, prolonging the construction period and wasting significant human, material, and financial resources.

[0007] Currently, the main conventional salvage tools include: (1) The expandable reverse-clamping retrieval spear is mainly used for retrieval and reverse-clamping operations of drill pipe and tubing couplings. It is a well workover tool that integrates retrieval, reverse-clamping, and circulating flushing. It is used in conjunction with an internal plugging tool when retrieval under pressure. The expandable reverse-clamping retrieval spear consists of three parts: an upper connector, an expansion sleeve, and an expansion mandrel. The upper part of the upper connector is connected to the drill string, the middle part is connected to the expansion mandrel by an internal thread, and the lower part is an internal hexagonal body. The upper part of the expansion mandrel is a connecting thread, the middle part is a cylindrical part, and the lower part is a conical body and a guide shoe part with a water passage in the middle. The upper part of the expansion sleeve is an external hexagonal shape, which matches the internal hexagonal part of the upper connector and can slide up and down. The lower part is an external thread with a longitudinal groove. However, if the fish gets stuck or cannot be reversed during retrieval or reverse-clamping, the tool is difficult to remove.

[0008] (2) Ordinary reverse-clamping spear: This tool is mainly used for retrieving and reversing stuck tubular parts such as downhole tubing and drill pipe. If the blockage is severe and cannot be reversed, the stuck part can be removed. This tool can be flushed and used in conjunction with internal plugging tools when retrieving under pressure. The ordinary reverse-clamping spear consists of an upper connector, spear shaft, spline sleeve, limit block, positioning screw, slips, and other parts. When removing the stuck part, the drill string needs to be driven down while rotating it in the opposite direction. It needs to be rotated at least 1-2 times, and more times for deep wells. However, repeatedly trying to rotate the drill string in the opposite direction can easily cause the drill string to loosen and fall into the well.

[0009] (3) Lifting and releasing type inverted hook retrieval spear: This tool is a retractable and recyclable inverted hook type tool specifically designed for retrieving hooks from inside cylindrical objects such as oil pipes and drill pipes. The spear shaft has a reversing track groove with one long and one short length. It can retrieve or release the hooked fish with a simple lift and release. It has the advantage that the tool does not need to be rotated to release the hooked fish and withdraw it. The tool structure mainly consists of an upper connector, spear shaft, inner sleeve, outer sleeve, sliding pin, and slips. However, if the hooked fish is stuck or cannot be opened, the tool is difficult to withdraw. Therefore, this tool is particularly suitable for minor repair work. Summary of the Invention

[0010] The purpose of this invention is to provide a hydraulically seated, pressurized, and interlocking salvage spear and salvage method to overcome the above-mentioned technical defects.

[0011] To solve the above-mentioned technical problems, the present invention provides a hydraulically seated, pressurized, interlocking salvage spear, comprising: The retrieval spear has a rod-sleeve structure with an axial central channel. The retrieval spear includes a threaded upper connector and a straightening sleeve. A spear rod is threadedly connected to the inner cavity of the upper connector. A slip is provided in the annular space formed by the spear rod and the straightening sleeve and fitted outside the spear rod. The slip and the spear rod are connected by a guide pin. The spear rod and the upper connector are connected by a set screw. The plugging part includes at least a hydraulic setting mechanism, a setting self-locking mechanism, and a hydraulic sealing mechanism. Hydraulic pressure is transmitted to the hydraulic setting mechanism via the retrieval spear part, which pushes the hydraulic sealing mechanism to compress and seal, while simultaneously pushing the setting self-locking mechanism to lock, so as to achieve setting and maintain sealing self-locking.

[0012] According to a hydraulically seated, pressurized, sealed, interlocking salvage spear, the spear shaft has a first axial center water eye for receiving the hydraulic pressure. The upper part of the spear shaft is machined with an L-shaped track groove for the guide pin to be inserted and slid. The outer wall of the middle part of the spear shaft is machined with a tapered surface, and multiple keys are machined around the tapered surface; The slip is a hollow cylindrical thin-walled slotted structure. The upper protruding part is machined with a round hole to install the guide pin. The middle and lower part is machined with multiple keyways to fit the multiple keys of the spear rod. The lower cylindrical protruding part is machined with an external thread that matches the coupling type of the oil pipe to be salvaged.

[0013] According to a hydraulically seated, pressurized, sealed, interlocking retrieval spear, the hydraulic seating mechanism includes: A central tube, the head of which is threaded to the tail of the spear shaft, and the tail of the central tube is threaded to the inner hole of the pilot cone. A piston is fitted in the lower section of the central tube. The piston and the pilot cone are connected by a seat seal shear pin. A second axial central water eye is opened in the axial center of the central tube. The first axial central water eye is connected to the second axial central water eye. A radial small water eye leading to the piston is opened in the lower section of the second axial central water eye. A hydraulic cylinder is fitted onto the outer circumference of the piston. The internal thread at the lower end of the hydraulic cylinder is connected to the external thread of the pilot cone, and a first set screw is installed on the threaded connection section of the two to prevent thread stripping.

[0014] According to a hydraulically seated, pressurized, sealed, interlocking retrieval spear, the seated self-locking mechanism includes: A spacer sleeve, fitted tightly against the middle section of the central tube, is a hollow circular tube. One end of the hollow circular tube extends horizontally along the circumference to form a disc, which is close to the top of the hydraulic cylinder. The hydraulic cylinder and the hollow circular tube form an annular cavity. A locking nut and a snap ring seat, fitted onto the hollow circular tube, are arranged from top to bottom within the annular cavity. The locking nut is screwed onto the inner wall of the upper section of the hydraulic cylinder. A snap ring latch is also machined on the inner wall of the upper section of the hydraulic cylinder, near the locking nut. The snap ring seat, in which the snap ring is embedded, is close to the piston. An unsealing shear pin seat, fitted onto the central tube, is arranged within the annular cavity formed by the piston, the snap ring seat, and the spacer sleeve. The unsealing shear pin seat and the snap ring seat are connected by an unsealing shear pin.

[0015] According to a hydraulically seated, pressurized, and interlocking salvage spear, the hydraulic sealing mechanism includes: Two long rubber tubes are provided between the spear shaft and the spacer, fitted onto the upper section of the central tube. One of the long rubber tubes is in close contact with the bottom end of the spear shaft, and the other long rubber tube is in close contact with the disc of the spacer. A short rubber tube is provided between the two long rubber tubes and fitted onto the central tube; A spacer ring fitted onto the central tube is provided between adjacent long and short rubber tubes.

[0016] According to a hydraulically seated, pressurized, sealed, interlocking retrieval spear, a second set screw is installed on the threaded connection section between the spear shaft and the central tube to prevent thread uncoupling.

[0017] This embodiment also provides a hydraulically seated, pressurized, interlocking method for retrieving fish, suitable for hydraulically seated, pressurized, interlocking spears, including the interlocking retrieval of fallen fish: Before the hydraulic seated pressurized sealing and interlocking retrieval spear is lowered into the well, the L-shaped track groove where the guide pin is located is rotated from the horizontal groove to the vertical groove. During the retrieval operation, the hydraulic seated pressurized sealing and interlocking retrieval spear is slowly lowered. When the hydraulic seated pressurized sealing and interlocking retrieval spear enters the fish, the slips are threaded and engaged with the upper connector thread of the fish. The hydraulic seated pressurized sealing and interlocking retrieval spear is slowly raised. The upper connector drives the spear shaft to move upward. The conical surface of the spear shaft expands the slips. The inner and outer conical surfaces of the slips engage to generate radial expansion force, causing the slips to bite the fish and achieve retrieval.

[0018] According to a hydraulic seated type pressurized sealing and interlocking retrieval method, the method further includes pressurizing the tubing to seat the rubber sleeve and seal the oil pipe: Pressurize the hydraulic seated type pressurized seal coupling spear. The hydraulic pressure passes through the radial water hole at the bottom of the central tube, pushing the piston upward to shear the seated shear pin. At the same time, it pushes the unsealing shear pin seat, the unsealing shear pin, the snap ring seat, the snap ring, and the spacer upward to compress the rubber sleeve, causing the rubber sleeve to expand and seal the inside of the oil pipe, thus achieving a seated seal. The snap ring on the snap ring seat engages with the snap ring lock of the hydraulic cylinder to maintain the rubber sleeve's sealing state. The rubber tube includes the long rubber tube and the short rubber tube.

[0019] According to a hydraulic seated type pressurized seal retrieving method, the method also includes reversing the thread to release it when it gets stuck. When the fish head gets stuck in the well and cannot be pulled up, first select an appropriate lifting force to tighten the slips and the internal thread of the fish head so that it can withstand the backlash torque of the lower drill string. The key on the cone surface of the spear rod can transmit the torque to the slips. Then rotate the drill string at a low speed to transmit the torque to the slips. The slips drive the stuck tubing to back up from the neutral point. The drilling tool mentioned refers to a hydraulically seated, pressurized, sealed, interlocking retrieval spear.

[0020] According to a hydraulic seated type pressurized seal retrieving method, the method also includes releasing or withdrawing the fallen fish: When the fish cannot be released due to the inverted connection, a load of 1-3t is applied to the lowered tubing. The slip teeth disengage from the conical key on the spear shaft and lose their supporting force. Simultaneously, the tubing is rotated 60°-90° in the tightening direction. The slips gradually disengage from the threaded female connector on the upper part of the fish, and are in the released state. Due to the friction between the long rubber tube, the short rubber tube, and the oil pipe, the load on the upper tubing exceeds 3t. The unsealing shear pin is sheared by tensile force. Under the action of hydraulic pressure and the elasticity of the rubber tube, the unsealing shear pin seat, the piston, and the spacer move downward. The long rubber tube and the short rubber tube are unsealed, and the fish can be completely released.

[0021] This invention relates to a hydraulically seated, pressurized, interlocking fishing spear and its method, solving the problem of difficulty in retrieving objects such as tubing couplings from the fish head under pressurized conditions downhole and at the wellhead. The tool is lowered for retrieval, hydraulically seated, and thus seals the tubing. The tool can be reversed for retrieval; the slips are rotated out in the tightening direction, and the plug is released when lifted. The tool exhibits excellent static and dynamic sealing performance. Pressurization within the tubing string causes the rubber sleeve to expand and seal the inside of the tubing. After seating, the rubber sleeve has a self-locking function, maintaining its dynamic sealing performance.

[0022] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of a hydraulically seated, pressurized, interlocking salvage spear.

[0024] Figure 2 This is a diagram showing the liquid flow direction of the upper half of a hydraulically seated, pressurized, interlocking salvage spear.

[0025] Figure 3 This is a diagram showing the liquid flow direction of the lower half of the hydraulically seated, pressurized, and interlocking salvage spear.

[0026] Figure 4 yes Figure 3 A magnified view of a portion of the image.

[0027] Explanation of reference numerals in the attached figures: 1-Upper connector; 2-Straightening sleeve; 3-Setting screw; 4-Guide pin; 5-Clip; 6-Spear rod; 7-Center tube; 8-Long rubber sleeve; 9-Spacer ring; 10-Short rubber sleeve; 11-Spacer sleeve; 12-Locking nut; 13-Hydraulic cylinder; 14-Snap ring seat; 15-Snap ring; 16-Unsealing shear pin seat; 17-Unsealing shear pin; 18-Piston; 19-Setting shear pin; 20-Piston cone; 21-First set screw; 22-First O-ring; 23-Second O-ring; 24-Second set screw; 25-Third O-ring; 26-Fourth O-ring. Detailed Implementation

[0028] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0029] It should be noted that, in this invention, the upper, lower, left, and right in the figure are regarded as the upper, lower, left, and right of the hydraulic seated type pressurized sealing snap-lock retrieval spear described in this specification.

[0030] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0031] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0032] This embodiment relates to a hydraulically seated, pressurized, interlocking salvage spear, which can lift 2-3 / 8", 2-7 / 8", and 3-1 / 2" thickened and unthickened oil pipes under pressure without the need for an oil pipe bridge plug or without the availability of an oil pipe bridge plug. The appropriate method can be selected depending on the application. Please refer to [link / reference]. Figure 1 and Figure 2 The hydraulic seated type pressurized sealing snap-lock retrieval spear includes a retrieval spear part and a plug part.

[0033] Specifically, the retrieval spear has a rod-sleeve structure with an axial central channel. The retrieval spear includes an upper connector 1 and a straightening sleeve 2 connected by threads. The spear rod 6 is threadedly connected to the inner cavity of the upper connector 1. The annular space formed by the spear rod 6 and the straightening sleeve 2 is provided with a slip 5 fitted outside the spear rod 6. The slip 5 and the spear rod 6 are connected by a guide pin 4. The spear rod 6 and the upper connector 1 are connected by a set screw 3.

[0034] The upper connector 1 and the straightening sleeve 2 are connected by threads. The inner hole of the straightening sleeve 2 is machined with internal threads, which are connected to the external threads on the upper part of the upper connector 1. The set screw 3 is built into the body of the straightening sleeve 2 to prevent the connection threads between the upper connector 1 and the straightening sleeve 2 from loosening.

[0035] Please see Figure 2 A first axial center water eye for receiving hydraulic pressure is provided at the axial center of the spear rod 6. A sealing ring groove and external thread are machined on the upper part of the spear rod 6, and a fourth O-ring 26 is installed in the sealing ring groove.

[0036] The spear shaft 6 transitions from a beveled surface to a cylindrical surface, and the body of the spear shaft 6 is lengthened. An internal thread is machined at the bottom of the inner hole of the spear shaft 6. At the same time, two set screw holes are machined on the spear shaft 6 to install the second set screw 24 to prevent the upper thread of the central tube 7 from unraveling.

[0037] The upper part of the spear shaft 6 is machined with an L-shaped track groove for the guide pin 4 to be inserted and slid. In some embodiments, the middle part of the spear shaft 6 is machined with two L-shaped track grooves, which are connected to the slip 5 through the guide pin 4 and are limited and centered through the inner hole of the straightening sleeve 2.

[0038] The outer wall of the middle part of the spear shaft 6 is machined with a tapered surface, and multiple keys are machined around the tapered surface. In some embodiments, the lower part of the spear shaft 6 is machined with a certain taper slope, and five straight keys and five oblique keyways are machined on the slope. The keyways on the tapered surface can fully fit with the slip 5, which is a split slip.

[0039] The kava 5 is a hollow cylindrical thin-walled slotted structure. The upper protruding part is machined with (e.g., two) round holes to install the guide pin 4. The middle and lower part is machined with multiple (e.g., five) keyways to match the multiple keys of the embedded spear rod 6. The lower cylindrical protruding part is machined with external threads that are consistent with the coupling type of the oil pipe to be salvaged.

[0040] The KAVA 5 can change direction on the L-shaped track groove via the guide pin 4, and achieve inverted retrieval by sitting on the conical keyway of the spear 6.

[0041] The segmented slip 5 is strong and elastic. When inspecting tools on the ground, the slip 5 is rotated from the horizontal groove of the L-shaped track into the vertical groove. When inserting the fish, it does not need to be rotated. As long as the segmented slip can enter the oil pipe thread to achieve a connection, the fish can be successfully retrieved. It has a very reliable retrieval function.

[0042] The plugging unit includes at least a hydraulic setting mechanism, a setting self-locking mechanism, and a hydraulic sealing mechanism. Hydraulic pressure is transmitted to the hydraulic setting mechanism via the retrieval spear, which pushes the hydraulic sealing mechanism to compress the seal, while simultaneously pushing the setting self-locking mechanism to lock, thereby achieving setting and maintaining the self-locking seal.

[0043] Please see Figures 1-3 The hydraulic sealing mechanism includes a central tube 7, the head of which is threaded to the tail of the spear 6. The tail of the central tube 7 is threaded to be inserted into the inner hole of the pilot cone 20. A piston 18 is fitted in the lower section of the central tube 7. The piston 18 and the pilot cone 20 are connected by a sealing shear pin 19. A second axial center water eye is opened in the axial center of the central tube 7. A first axial center water eye is connected to the second axial center water eye. A radial small water eye leading to the piston 18 is opened in the lower section of the second axial center water eye.

[0044] In some embodiments, a sealing ring groove is machined at the top of the central tube 7, and external threads are machined at the top and bottom respectively. A third O-ring 25 is installed in each of the upper sealing ring grooves. The top external thread is connected to the bottom internal thread of the spear 6, and the lower external thread is connected to the internal thread of the pilot cone 20.

[0045] In some embodiments, two radial water holes are provided at the lower external thread of the central tube 7. The two radial water holes are connected to the inner cavity formed by the piston 18, the hydraulic cylinder 13, etc. The central tube 7, the spear rod 6, and the upper connector 1 form an axial combination of water holes.

[0046] Please see Figure 3 The hydraulic cylinder 13 is fitted onto the outer circle of the piston 18. The internal thread at the lower end of the hydraulic cylinder 13 is connected to the external thread of the taper 20, and the threaded connection section of the two is equipped with a first set screw 21 to prevent the thread from being unthreaded.

[0047] In some embodiments, two long rubber tubes 8, two spacer rings 9, and one short rubber tube 10 are sequentially installed in the upper middle part of the central tube 7; a spacer sleeve 11, a locking nut 12, a hydraulic cylinder 13, a snap ring seat 14, an unsealing shear pin seat 16, a piston 18, and a guide cone 20 are installed behind the rubber tubes.

[0048] For details, please continue reading Figure 3The self-locking mechanism includes a spacer 11, which is fitted tightly against the middle section of the central tube 7. The spacer 11 is a hollow circular tube. One end of the hollow circular tube extends horizontally along the circumference to form a disc. The disc is close to the top of the cylinder 13. The cylinder 13 and the hollow circular tube form an annular cavity. In the annular cavity, a locking nut 12 and a snap ring seat 14 are fitted from top to bottom and fitted onto the hollow circular tube. The locking nut 12 is screwed onto the inner wall of the upper section of the cylinder 13. A snap ring latch is also machined on the inner wall of the upper section of the cylinder 13 near the locking nut 12. The snap ring seat 14, which is fitted with a snap ring 15, is close to the piston 18. The annular cavity formed by the piston 18, the snap ring seat 14 and the spacer 11 is fitted with a release shear pin seat 16, which is fitted onto the central tube 7. The release shear pin seat 16 and the snap ring seat 14 are connected by a release shear pin 17.

[0049] The upper and lower ends of the hydraulic cylinder 13 are machined with internal threads. The upper internal thread is connected to the locking nut 12. A snap ring is machined behind the upper internal thread of the hydraulic cylinder 13. The lower internal thread is connected to the external thread of the guide cone 20. At the same time, a set screw hole is machined in the lower part of the hydraulic cylinder 13 to install the first set screw 21 to prevent the connection thread with the guide cone 20 from being unthreaded.

[0050] The snap ring seat 14 and the release pin seat 16 are built into the hydraulic cylinder 13 and can slide up and down along the central tube 7 through clearance fit; the upper part of the snap ring seat 14 has two annular grooves and two snap rings 15 are installed. The snap rings 15 can sit on the snap ring latch (sawtooth snap ring) and lock themselves.

[0051] In some embodiments, the lower part of the snap ring seat 14 has four screw holes, and four release screws 17 are installed thereon. The snap ring seat 14 and the release screw seat 16 are connected together by the four release screws 17. The release screw seat 16 is a cylindrical structure with an annular groove machined in the middle, and the four release screws 17 are installed in the annular groove.

[0052] Spacer 11 is a hollow tube with a disc. The disc is placed in front of the locking nut 12. The hollow tube is fitted into the inner hole of the snap ring seat 14 and rests on the release shear pin seat 16.

[0053] The piston 17 has a circular hole structure, with two sealing ring grooves machined on the upper outer circle and the inner hole respectively; the outer circle mates with the hydraulic cylinder 13 and is equipped with two second O-ring seals 23; the inner hole mates with the central tube 7 and is equipped with two sealing rings 22; the lower part of the piston 18 is machined with one ring groove.

[0054] The upper part of the guide cone 20 is machined with four shear pin holes, which are connected to the piston 18 via the seat seal shear pin 19.

[0055] The middle circumference of the guide cone 20 is machined with external threads, which can be connected to the hydraulic cylinder 13. There is a sealing ring groove in front of the external thread, and a second O-ring 23 is installed. The interior of the guide cone 20 is a stepped hole. The guide cone 20 is machined with internal threads, which can be connected to the external threads at the bottom of the central tube 7. The bottom of the guide cone is a solid conical spherical body.

[0056] Please see Figures 1-3 The hydraulic sealing mechanism includes two long rubber cylinders 8 installed between the spear rod 6 and the spacer 11, which are fitted onto the upper section of the central tube 7. One of the long rubber cylinders 8 is in close contact with the bottom end of the spear rod 6, and the other long rubber cylinder 8 is in close contact with the disc of the spacer 11.

[0057] A short rubber sleeve 10 is provided between the two long rubber sleeves 8 and fitted into the central tube 7. A spacer ring 9 is provided between adjacent long rubber sleeves 8 and short rubber sleeves 10 and fitted into the central tube 7. By pressurizing inside the tubing, the rubber sleeve expands and seals the inside of the oil pipe. After the rubber sleeve is sealed, it has a self-locking function and can maintain the dynamic sealing performance of the rubber sleeve.

[0058] A second set screw 24 is installed at the threaded connection section between the spear shank 6 and the central tube 7 to prevent thread unraveling.

[0059] The third O-ring 25 and the fourth O-ring 26 are used to prevent gas leakage, while the first O-ring 22 and the second O-ring 23 are used to prevent liquid leakage.

[0060] The hydraulic cylinder 13, piston 18, central tube 7, guide cone 20, setting shear pin 19, first O-ring 22 and second O-ring 23 constitute a hydraulic setting mechanism; the snap ring seat 14, the sawtooth-shaped latch (i.e. snap ring latch) in the hydraulic cylinder 13, and the spacer 11 constitute a setting execution mechanism; two long rubber tubes 8, two spacer rings 9, and one short rubber tube 10 constitute a hydraulic sealing mechanism; the unsealing shear pin seat 16 and the unsealing shear pin 17 constitute an unsealing mechanism, and the locking nut 12 is a limiting mechanism.

[0061] The central tube 7, long rubber tube 8, spacer ring 9, short rubber tube 10, spacer sleeve 11, locking nut 12, hydraulic cylinder 13, snap ring seat 14, snap ring 15, release shear pin seat 16, release shear pin 17, piston 18, setting shear pin 19, guide cone 20, set screw 21, first O-ring 22, second O-ring 23, third O-ring 25, and fourth O-ring 26, together form a rod-shaped structure with an axial central semi-through water hole.

[0062] This embodiment also provides a hydraulically seated, pressurized, interlocking method for retrieving fish, suitable for retrieving spears using hydraulically seated, pressurized, interlocking techniques. The hydraulically seated, pressurized, interlocking method includes step A: retrieving the fallen fish by interlocking the seals. Before the hydraulic seated pressurized sealing and interlocking retrieval spear is lowered into the well, the L-shaped track groove where the guide pin 4 is located is rotated from the horizontal groove to the vertical groove. During the retrieval operation, the hydraulic seated pressurized sealing and interlocking retrieval spear is slowly lowered. When the hydraulic seated pressurized sealing and interlocking retrieval spear enters the fish, the slip 5 is interlocked and fitted with the threaded joint of the upper part of the fish. The hydraulic seated pressurized sealing and interlocking retrieval spear is slowly lifted. The upper joint 1 drives the spear rod 6 to move upward. The conical surface of the spear rod 6 expands the slip 5. The inner and outer conical surfaces of the slip 5 fit together to generate radial expansion force, so that the slip 5 bites the fish and achieves retrieval.

[0063] The hydraulic seated pressurized seal retrieving method also includes step B, pressurizing the tubing to seat the rubber sleeve and seal the oil tubing: Pressurize the hydraulic seated type pressurized seal coupling spear. The hydraulic pressure passes through the radial water hole at the bottom of the central tube 7, pushing the piston 18 upward to shear the seated shear pin 19. At the same time, it pushes the release shear pin seat 16, release shear pin 17, snap ring seat 14, snap ring 15, and spacer 11 upward to compress the rubber sleeve, causing the rubber sleeve to expand and seal the inside of the oil pipe, thus achieving a seated seal. The snap ring 15 on the snap ring seat 14 engages with the snap ring lock of the hydraulic cylinder 13 to maintain the rubber sleeve's sealing state. The rubber tubes include a long rubber tube 8 and a short rubber tube 10.

[0064] The hydraulic seated pressurized seal retrieving method also includes step C: when the tubing is stuck, reverse the thread to release the stick. When the fish head gets stuck in the well and cannot be pulled up, first select an appropriate lifting force to tighten the slip 5 and the internal thread of the fish head so that it can withstand the backlash torque of the lower drill string. The key on the cone surface of the spear rod 6 can transmit the torque to the slip 5. Then rotate the drill string at a low speed to transmit the torque to the slip 5. The slip 5 drives the stuck string to back up from the neutral point. The drilling tool refers to a hydraulically seated, pressurized, sealed, interlocking fishing spear.

[0065] The hydraulic seated, pressurized, interlocking fishing method also includes step D: releasing or removing the fallen fish. When the fish cannot be released due to the inverted connection, the lowering of the tubing string applies a load of 1-3t. The slip 5 disengages from the conical key on the spear shank 6 and loses its supporting force. At the same time, the tubing string is rotated 60°-90° in the tightening direction. The slip 5 gradually disengages from the threaded female thread of the upper connector of the fish, and is in the released state. Due to the friction between the long rubber sleeve 8, the short rubber sleeve 10 and the oil pipe, the load of the upper tubing string exceeds 3t. The shear pin 17 is sheared by tension. Under the action of hydraulic pressure and the elasticity of the rubber sleeve, the shear pin seat 16, piston 18 and spacer 11 move downward. The long rubber sleeve 8 and the short rubber sleeve 10 are unsealed, and the fish can be completely released.

[0066] In practical applications, if it is necessary to perform pressurized reverse-threaded retrieval of broken or fallen tubing, or to remove tubing hangers, a hydraulically seated, pressurized, sealed, reverse-threaded retrieval spear with a reverse-threaded upper connector 1 can be selected. Before construction, check that the connecting threads of the upper connector 1 are intact and the tightness is reasonable; the slips 5 must match the threads of the tubing to be retrieved, the threads must be intact and undamaged, and the upper and lower movable guide pins 4 can be flexibly reversed without obstruction; check whether the first O-ring 22, the second O-ring 23, the third O-ring 25, the fourth O-ring 26, the long rubber sleeve 8, and the short rubber sleeve 10 are intact, and replace them in time if there is any damage; check whether the set screw 3 and the first set screw 21 and the second set screw 24 are intact and in place; check whether the unsealing shear pin 17 and the setting shear pin 19 are intact; check whether the connections of each part are tight; after meeting the well entry conditions, connect the pressurized, sealed, reverse-threaded retrieval spear + reverse-threaded safety connector + reverse-threaded drill pipe in sequence and enter the well.

[0067] After completing the above tasks, perform the following operations: Step A: Use the hook to retrieve the fallen fish. The reverse-threaded hydraulic seated pressurized sealing fishing spear includes the upper connector 1, the inner stepped hole of the centering sleeve 2, the threads at both ends of the central tube 7, and the external threads of the guide cone 20, all of which are reverse-threaded. The horizontal groove of the L-shaped trajectory on the spear rod 6 is arranged to the left. Before the tool enters the well, the slips 5 are rotated from the horizontal groove of the L-shaped trajectory to the vertical groove. During the fishing operation, the drill string is slowly lowered. When the tool enters the fish, the slips 5 are aligned and engaged with the threaded female thread of the connector on the upper part of the fish. The tubing string is slowly lifted, and the upper connector drives the spear rod 6 to move upward. The conical surface of the spear rod 6 expands and splits the slips 5. The inner and outer conical surfaces of the slips 5 fit together to generate radial expansion force, causing the slips to bite the fish and achieve fishing.

[0068] Step B: Pressurize the tubing to seal the rubber sleeve and seal the oil tubing. Pressurize the tubing to 10-20 MPa. Hydraulic pressure flows through the two inlets at the bottom of the central tube 7. The setting shear pin 19 is sheared by the hydraulic force, pushing the piston 18 upwards. The piston 18 pushes the unsealing shear pin seat 16, unsealing shear pin 17, snap ring seat 14, snap ring 15, and spacer 11 upwards, compressing the rubber sleeve to expand the sealing seal. The rubber sleeve relies on its elasticity to seal the oil pipe. The snap ring 15 is self-locked to the serrated snap ring inside the hydraulic cylinder 13, maintaining a constant pressure to keep the rubber sleeve sealed, preventing it from dislodging even during tripping out of the drill string. Perform a test pull under pressure; if the sticking is broken, retrieve all drill string.

[0069] Step C: If the tubing gets stuck, reverse the pin to release the stick. When the downhole chuck gets stuck and repeated attempts to release it fail, the slips are tightened against the internal threads of the chuck head to withstand the back-threading torque required to open the lower drill string. The neutralization point is precisely selected, and an appropriate lifting force is chosen, taking into account the cross-sectional force of the tubing string (uplift force) and the friction at the wellhead. The key on the cone surface of the spear shank 6 transmits torque to the split slips 5. Then, the drill string is rotated at a low speed to transfer the torque to the slips, which then drive the stuck tubing string to open from the neutralization point. For example, in a gas field, if the downhole choke fails in some horizontal wells and needs to be replaced under pressure, we often use 50-100m below the choke as the neutralization point for back-threading operations; then, the tubing string is lowered for pressure reconnection. For example, if the downhole drilling tools of some production wells in a gas field get stuck, before well workover, the tubing hanger needs to be moved out or pulled up and backed out. A reverse-threaded drill pipe sub with a hydraulic seated pressurized seal and reeling spear is then lowered in. The tubing hanger is moved and raised above the slip blowout preventer. The slip blowout preventer is then closed, and an active rotary table is used at the wellhead for reverse threading to retrieve the tubing hanger.

[0070] Step D: Release or remove the fish. When the fish cannot be released due to the inverted connection, the tubing is lowered to apply a load of 1-3t. The slip 5 disengages from the conical key on the spear shank 6 and loses its supporting force. At the same time, the tubing is rotated 60°-90° in the tightening direction. The split slip 5 gradually disengages from the threaded joint of the upper part of the fish, and is in the released state. Due to the friction between the long rubber sleeve 8, the short rubber sleeve 10 and the oil pipe, the tubing is lifted. The lifting load exceeds 3t, and the shear pin 17 is sheared by tension. Under the action of hydraulic pressure and the elasticity of the rubber sleeve, the shear pin seat 16, piston 18 and spacer 11 move downward. The long rubber sleeve 8 and the short rubber sleeve 10 are unsealed, and the fish can be completely released.

[0071] If the device's internal cavity height is limited or the threads cannot be unscrewed, it is often necessary to cut the tubing and downhole tools that have been pulled out of the well. The upper coupling of the cut tubing can be retrieved under pressure using this tool; it can also retrieve tubing that has fallen into the well but is not stuck. In this case, a hydraulic seated sealing type pressurized sealing and snap-locking retrieval spear with the upper connector 1 being positively threaded can be selected.

[0072] Before construction, check that the upper connector thread is intact and the tightness is reasonable; the slip 5 must match the thread of the tubing to be retrieved, the thread is intact and undamaged, and the upper and lower movable guide pins 4 can be flexibly reversed without jamming; check whether the first O-ring 22, the second O-ring 23, the third O-ring 25, the fourth O-ring 26, the long rubber sleeve 8, and the short rubber sleeve 10 are intact, and replace them in time if there is any damage; check whether the set screw 3, the first set screw 21, and the second set screw 24 are intact and in place; check whether the unsealing shear pin 17 and the setting shear pin 19 are intact; check whether all connections are tight; after the conditions for entering the well are met, connect the pressurized sealing coupling retrieval spear + tool tubing (new) in sequence and enter the well.

[0073] After completing the above tasks, perform the following operations: Step A: Use the hook to retrieve the fallen fish. The hydraulically sealed, pressurized, and interlocking fishing spear features a positive-threaded design, including the upper connector 1, the inner stepped hole of the centering sleeve 2, the threads at both ends of the central tube 7, and the external threads of the guide cone 20. The horizontal groove of the L-shaped trajectory on the spear shaft 6 is positioned to the right. Before the tool enters the well, the slips 5 are rotated from the horizontal groove of the L-shaped trajectory to the vertical groove. During the fishing operation, the drill string is slowly lowered. Once the tool enters the fish, the slips 5 are interlocked with the threaded female connector on the upper part of the fish and then slowly lifted. The upper connector moves the spear shaft 6 upwards, causing the cone surface of the spear shaft 6 to expand and split the slips 5. The inner and outer cone surfaces of the slips 5 come together to generate radial expansion force, causing the slips to grip the fish and achieve retrieval.

[0074] Step B: Pressurize the tubing to seal the rubber sleeve and seal the oil tubing. Pressurize the tubing to 10-20 MPa ±. Hydraulic pressure flows through the two water inlets at the bottom of the central tube 7. The setting shear pin 19 is sheared by the hydraulic force, and the hydraulic pressure pushes the piston 18 upward. The piston 18 pushes the unsealing shear pin seat 16, unsealing shear pin 17, snap ring seat 14, snap ring 15, and spacer 11 upward, compressing the rubber sleeve to expand the setting seal. The rubber sleeve relies on its elasticity to seal the oil pipe. The snap ring 15 is self-locked with the serrated buckle inside the hydraulic cylinder 13, maintaining the sealing state of the rubber sleeve with constant pressure, so that it will not be unsealed even during tripping out of the drill string. Test pull under pressure; if it is unstuck, pull out all drill strings.

[0075] Step C, pressurize and remove the fish. Wellhead pressurized cut tubing couplings and downhole tools.

[0076] Step D, remove the fish from the ground. Withdraw the fish from the ground, strike the slipper 5, rotate the tube column 60°-90° clockwise, change the direction of the guide pin 4 to the transverse groove, release the slipper, remove the second set screw 24, remove the spear rod 6, and take out the long rubber tube 8, the short rubber tube 10, and the remaining part of the plug.

[0077] In the above, the neutral point refers to the point in the tubing string where there is neither tension nor compression, and the axial stress is zero. When performing a pressurized seal undercut, the undercut position must be determined based on the neutral point. By adjusting the lifting load, the tubing string joint to be undercut is brought to the neutral point state.

[0078] The hydraulic seated, pressurized, sealing, and interlocking retrieval spear and method provided in this embodiment can replace tubing bridge plugs, exhibiting outstanding sealing performance. In laboratory sealing tests, it withstands a static pressure of 35 MPa, a temperature of 150°C, and is resistant to hydrogen sulfide and carbon dioxide corrosion. This invention allows for convenient and easy withdrawal by pressing down the drill string, rotating it 60-90 degrees, and then lifting it upwards for safe operation—a feature not found in other comparative tools. This meets the needs of on-site construction for pressurized well workover and retrieval operations. It is suitable not only for reverse-locking retrieval of oil and gas wells but also for reverse-locking retrieval of water injection wells. Furthermore, depending on process requirements, a safety joint can be connected to the wellhead string, and reverse-locking drill pipe or tubing can be used for wellhead entry operations.

[0079] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A hydraulically seated, pressurized, sealed, interlocking retrieval spear, characterized in that, include: The retrieval spear has a rod-sleeve structure with an axial central channel. The retrieval spear includes a threaded upper connector (1) and a straightening sleeve (2). A spear rod (6) is threadedly connected to the inner cavity of the upper connector (1). A slip (5) is provided in the annular space formed by the spear rod (6) and the straightening sleeve (2) and is fitted outside the spear rod (6). The slip (5) and the spear rod (6) are connected by a guide pin (4). The spear rod (6) and the upper connector (1) are connected by a set screw (3). The plugging part includes at least a hydraulic setting mechanism, a setting self-locking mechanism, and a hydraulic sealing mechanism. Hydraulic pressure is transmitted to the hydraulic setting mechanism via the retrieval spear part, which pushes the hydraulic sealing mechanism to compress and seal, while simultaneously pushing the setting self-locking mechanism to lock, so as to achieve setting and maintain sealing self-locking.

2. The hydraulically seated, pressurized, sealed, interlocking retrieval spear according to claim 1, characterized in that, The spear shaft (6) has a first axial center water eye for receiving the hydraulic pressure at its axial center. The upper part of the spear shaft (6) is machined with an L-shaped track groove for the guide pin (4) to be inserted and slid. The outer wall of the middle part of the spear shaft (6) is machined with a conical surface, and multiple keys are machined around the conical surface; The slip (5) is a hollow cylindrical thin-walled slotted structure. The upper protruding part is machined with a round hole to install the guide pin (4). The middle and lower part is machined with multiple keyways to fit the multiple keys of the spear rod (6). The lower cylindrical protruding part is machined with an external thread that matches the coupling type of the oil pipe to be salvaged.

3. The hydraulically seated, pressurized, sealed, interlocking retrieval spear according to claim 2, characterized in that, The hydraulic sealing mechanism includes: The head of the central tube (7) is threaded to the tail of the spear rod (6), and the tail of the central tube (7) is threaded to the inner hole of the insertion cone (20). A piston (18) is fitted on the lower section of the central tube (7). The piston (18) and the insertion cone (20) are connected by a seat seal shear pin (19). A second axial center water eye is opened at the axial center of the central tube (7). The first axial center water eye is connected to the second axial center water eye. A radial small water eye leading to the piston (18) is opened at the lower section of the second axial center water eye. The hydraulic cylinder (13) is fitted on the outer circle of the piston (18). The internal thread at the lower end of the hydraulic cylinder (13) is connected to the external thread of the lead cone (20), and the threaded connection section of the two is equipped with a first set screw (21) to prevent the thread from being unthreaded.

4. The hydraulically seated, pressurized, sealed, interlocking retrieval spear according to claim 3, characterized in that, The self-locking mechanism of the seat seal includes: A spacer (11) is fitted tightly against the middle section of the central tube (7). The spacer (11) is a hollow circular tube. One end of the hollow circular tube extends horizontally along the circumference to form a disc. The disc is close to the top of the liquid cylinder (13). The liquid cylinder (13) and the hollow circular tube form an annular cavity. A locking nut (12) and a snap ring seat (14) fitted onto the hollow circular tube are provided from top to bottom in the annular cavity. The locking nut (12) is screwed onto the liquid cylinder (7). 3) The upper inner wall of the cylinder (13) is also machined with a snap ring lock near the locking nut (12). The snap ring seat (14) with snap ring (15) is close to the piston (18). The annular cavity formed by the piston (18), the snap ring seat (14) and the spacer (11) is provided with a release shear pin seat (16) fitted on the central tube (7). The release shear pin seat (16) and the snap ring seat (14) are connected by release shear pin (17).

5. The hydraulically seated, pressurized, sealed, interlocking retrieval spear according to claim 4, characterized in that, The hydraulic sealing mechanism includes: Two long rubber tubes (8) are provided between the spear shaft (6) and the spacer (11) and are fitted onto the upper section of the central tube (7). One of the long rubber tubes (8) is close to the bottom end of the spear shaft (6), and the other long rubber tube (8) is close to the disc of the spacer (11). A short rubber tube (10) is provided between the two long rubber tubes (8) and fitted onto the central tube (7). A spacer ring (9) fitted onto the central tube (7) is provided between adjacent long rubber tubes (8) and short rubber tubes (10).

6. The hydraulically seated, pressurized, sealed, interlocking retrieval spear according to claim 3, characterized in that, A second set screw (24) is installed on the threaded connection section of the spear shaft (6) and the central tube (7) to prevent the threads from unraveling.

7. A hydraulically seated, pressurized, interlocking method for retrieving a spear, suitable for the hydraulically seated, pressurized, interlocking spear retrieving spear described in claim 5, characterized in that... Including the retrieval of fallen fish using a snap hook: Before the hydraulic seated pressurized sealing hook-and-loop retrieval spear enters the well, the L-shaped track groove where the guide pin (4) is located is rotated from the horizontal groove to the vertical groove. During the retrieval operation, the hydraulic seated pressurized sealing hook-and-loop retrieval spear is slowly lowered. When the hydraulic seated pressurized sealing hook-and-loop retrieval spear enters the fish, the slip (5) is threaded and fitted with the upper part of the fish. The hydraulic seated pressurized sealing hook-and-loop retrieval spear is slowly lifted. The upper connector (1) drives the spear rod (6) to move upward. The conical surface of the spear rod (6) expands the slip (5). The inner and outer conical surfaces of the slip (5) fit together to generate radial expansion force, so that the slip (5) bites the fish and achieves retrieval.

8. The hydraulic seated type pressurized seal retrieving method according to claim 7, characterized in that, This also includes pressurizing the tubing to seal the rubber sleeve and seal the oil tubing: Pressurize the hydraulic seated type pressurized seal hook-and-loop retrieval spear. The hydraulic pressure passes through the radial small water hole at the bottom of the central tube (7) and pushes the piston (18) upward to cut the seated shear pin (19). At the same time, it pushes the unsealing shear pin seat (16), the unsealing shear pin (17), the snap ring seat (14), the snap ring (15), and the spacer (11) upward to compress the rubber tube, so that the rubber tube expands and seals the inside of the oil pipe to achieve seating. The snap ring (15) on the snap ring seat (14) engages with the snap ring lock of the hydraulic cylinder (13) to maintain the rubber tube sealing state. The rubber tube includes the long rubber tube (8) and the short rubber tube (10).

9. The hydraulic seated type pressurized seal interlocking salvage method according to claim 7, characterized in that, This also includes handling pipe jams and reversing the clamp to release them: When the fish head gets stuck and cannot be pulled up, first select an appropriate lifting force to tighten the slip (5) and the internal thread of the fish head so that it can withstand the backlash torque of the lower drill string. The key on the cone surface of the spear rod (6) can transmit the torque to the slip (5). Then rotate the drill string at a low speed to transmit the torque to the slip (5). The slip (5) drives the stuck string to back up from the neutral point. The drilling tool mentioned refers to a hydraulically seated, pressurized, sealed, interlocking retrieval spear.

10. The hydraulic seated type pressurized seal retrieving method according to claim 7, characterized in that, This also includes releasing or removing the fish that have fallen into the water: When the fish cannot be released due to the inverted design, the lowering column is subjected to a load of 1-3t. The slip teeth (5) disengage from the conical key on the spear rod (6) and lose their supporting force. At the same time, the column is rotated 60°-90° in the tightening direction. The slip teeth (5) gradually disengage from the threaded female thread of the upper connector of the fish and are in the released state. Due to the friction between the long rubber tube (8), the short rubber tube (10) and the oil pipe, the load on the upper column exceeds 3t. The unsealing shear pin (17) is sheared by tension. Under the action of hydraulic pressure and the elasticity of the rubber tube, the unsealing shear pin seat (16), the piston (18), and the spacer (11) move downward. The long rubber tube (8) and the short rubber tube (10) are unsealed, and the fish can be completely released.

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