Coiled tubing cutting and fishing integrated tool

Abstract

The application discloses a coiled tubing cutting and fishing integrated tool and relates to the technical field of oil and natural gas. The tool comprises coaxially arranged upper end connectors, a barrel and lower end connectors, the upper end connectors are connected to the upper end of the barrel, and the lower end connectors are connected to the lower end of the barrel; the barrel is internally sequentially arranged from top to bottom along the axial direction of the barrel with an elastic pre-tightening piece, a bearing base, a clamping slip, a first cone sleeve, a cutting knife set and a second cone sleeve; the first cone sleeve is limitingly connected with the barrel through a shearing limiting piece, the outer wall of the clamping slip is matched with the inner wall taper surface of the first cone sleeve, and the inner wall of the cutting knife set is matched with the outer wall taper surface of the second cone sleeve; and a central passage is formed on the inner side of the barrel, which can be penetrated by the coiled tubing from the lower end connector and axially penetrated. The tool can solve the problems that the coiled tubing cutting and fishing tool can only cut and fish short sections of the oil pipe near the fish top during operation, can only cut and fish the coiled tubing in sections through multiple tripping, cutting and fishing in sections, and is complicated in construction and low in operation efficiency.

Description

Technical Field

[0001] This application relates to the field of oil and gas technology, and in particular to an integrated tool for cutting and retrieving coiled tubing. Background Technology

[0002] In oil and gas well workover operations, when coiled tubing gets stuck downhole, forming a "fish" (a type of tubing that has fallen into the well), it is a common failure mode where the lower end of the "fish" is stuck inside the well while the upper tubing string is suspended in the air. To deal with this type of failure, cutting and retrieval tools need to be lowered into the field to retrieve the stuck "fish".

[0003] However, existing continuous tubing cutting and retrieval tools can only be used to insert fish at the top of the fish and cut and retrieve short sections of tubing near the top. For fish falling into long continuous tubing, multiple drilling and retrieval operations are required, which is cumbersome and inefficient.

[0004] Therefore, the above problems urgently need to be solved. Summary of the Invention

[0005] The purpose of this application is to provide an integrated tool for cutting and retrieving continuous tubing, which solves the problem that existing tools can only be used to insert fish at the top of the fish and cut and retrieve short sections of tubing near the top. For long continuous tubing fish, multiple drilling and retrieval operations are required, resulting in cumbersome construction procedures and low work efficiency.

[0006] To address the aforementioned technical problems, the embodiments of this application provide the following technical solutions: This application provides an integrated tool for cutting and retrieving coiled tubing, comprising: The upper end connector, the cylinder body, and the lower end connector are coaxially arranged. The upper end connector is connected to the upper end of the cylinder body, and the lower end connector is connected to the lower end of the cylinder body. The cylinder is arranged from top to bottom along its axial direction as follows: elastic pre-tightening element, bearing base, clamping slip, first cone sleeve, cutting blade assembly and second cone sleeve; The first cone sleeve is connected to the cylinder by a shearing limiting component, the second cone sleeve is connected to the inner wall of the cylinder by a limiting component, the outer wall of the clamping slip is adapted to the inner cone surface of the first cone sleeve, and the inner wall of the cutting blade assembly is adapted to the outer cone surface of the second cone sleeve. A central channel is formed inside the cylinder, allowing a continuous tubing to pass through from the lower end joint and axially.

[0007] In some embodiments, the aforementioned integrated tool for cutting and salvaging continuous tubing includes an upper connector with a limiting shoulder at the second end, the limiting shoulder having a gap space with the cylinder; the upper end of the elastic pretensioner abuts against the upper connector within the gap space, and the lower end of the elastic pretensioner abuts against the bearing base.

[0008] In some embodiments, the aforementioned integrated tool for cutting and salvaging continuous tubing includes multiple guide keys arranged circumferentially on the outer wall of the support base, the guide keys extending axially, and guide grooves corresponding to the guide keys being opened on the inner wall of the cylinder, with the guide keys slidably embedded in the guide grooves.

[0009] In some embodiments, the aforementioned integrated tool for cutting and retrieving coiled tubing includes multiple first opening slots evenly spaced circumferentially on the side of the clamping slips facing the first conical sleeve. The first opening slots are non-through, and their openings face the first conical sleeve. The outer wall of the clamping slips between adjacent first opening slots is adapted to the conical surface of the inner wall of the first conical sleeve.

[0010] In some embodiments, the aforementioned integrated tool for cutting and salvaging continuous tubing includes a cutting blade assembly with multiple second opening slots evenly spaced circumferentially on the side facing the second conical sleeve. The second opening slots are non-through and their openings face the second conical sleeve. The cutting blade assembly includes multiple cutting structures located between adjacent second opening slots. The inner wall of the cutting structure facing the second conical sleeve is provided with cutting teeth, and the cutting edges of the cutting teeth face the central channel.

[0011] In some embodiments, the aforementioned integrated tool for cutting and salvaging continuous tubing includes a limiting sleeve between the first cone sleeve and the cutting blade assembly, with the outer edge of the limiting sleeve being adapted to and connected to the inner wall of the cylinder.

[0012] In some embodiments, the aforementioned integrated tool for cutting and retrieving coiled tubing includes a protrusion structure on the outer wall of the second cone sleeve and a groove structure on the inner wall of the cylinder. The protrusion structure and the groove structure are adapted to each other so that the second cone sleeve is limited and connected to the cylinder.

[0013] In some embodiments, the aforementioned integrated tool for cutting and retrieving coiled tubing includes a straightening extension cylinder provided between the second cone sleeve and the lower end connector; the outer wall of the first end of the straightening extension cylinder in the axial direction is provided with a first external thread, which is used to thread-connect the inner wall of the cylinder; the second end of the straightening extension cylinder in the axial direction is provided with a first inner hole, the wall of the first inner hole is provided with an internal thread, which is used to thread-connect the lower end connector.

[0014] In some embodiments, the aforementioned integrated tool for cutting and retrieval of coiled tubing includes a second external thread on the outer wall of the first end of the lower end connector in the axial direction, the second external thread being used for threaded connection with the internal thread; and a second inner hole on the second end of the lower end connector in the axial direction, the inner diameter of the second inner hole on the side away from the straightening extension cylinder being larger than the inner diameter on the side facing the straightening extension cylinder.

[0015] In some embodiments, the aforementioned integrated tool for cutting and retrieving coiled tubing includes a friction assembly on the inner wall of the clamping slips facing the central channel. The friction assembly includes a plurality of friction elements arranged in an array, which are used to conform to the outer wall of the coiled tubing.

[0016] By employing the above technical solution, the integrated tool for continuous tubing cutting and retrieval of the present invention has at least the following advantages: This application provides an integrated tool for cutting and retrieving coiled tubing, comprising: an upper end connector, a cylinder, and a lower end connector arranged coaxially, the upper end connector being connected to the upper end of the cylinder, and the lower end connector being connected to the lower end of the cylinder; inside the cylinder, from top to bottom along its axial direction, are arranged an elastic pre-tightening member, a bearing base, a clamping slip, a first conical sleeve, a cutting blade assembly, and a second conical sleeve; the first conical sleeve is limited and connected to the cylinder through a shearing limiting member, and the second conical sleeve is limited and connected to the inner wall of the cylinder; the outer wall of the clamping slip is adapted to the conical surface of the inner wall of the first conical sleeve, and the inner wall of the cutting blade assembly is adapted to the conical surface of the outer wall of the second conical sleeve; a central channel is formed inside the cylinder, allowing the coiled tubing to pass through from the lower end connector and axially. This application's tool adopts an integrated structure with the upper connector, cylinder, and lower connector arranged coaxially. Combined with a central channel running axially through the cylinder, the tool can be directly fitted onto the outside of the coiled tubing. Suspended by the drill string, it descends along the outer wall of the coiled tubing to the base of the fish for operation, overcoming the limitation of existing tools that can only insert the fish at the top. Inside the cylinder, along the axial direction, are arranged an elastic preload, a bearing base, clamping slips, a first cone sleeve, a cutting blade assembly, and a second cone sleeve. The two independent conical surfaces of the first and second cone sleeves respectively drive the clamping slips and the cutting blade assembly, enabling the clamping and cutting processes to be executed step-by-step. Simultaneously, the first cone sleeve is connected to the cylinder via a shearing limiter, locking the position of internal components during descent and preventing malfunctions. The tool can descend directly to the root of the fish in a long section of coiled tubing, completing the entire process of clamping, positioning, and cutting the tubing in one go at the root. After cutting, the entire suspended coiled tubing section can be retrieved along with the tool, eliminating the need for multiple drilling operations and segmented cutting and retrieval, thus simplifying the construction process and effectively improving the retrieval efficiency of fish in long coiled tubing. This application solves the problem that existing coiled tubing cutting and retrieval tools can only insert the fish at the top and cut and retrieve short sections of tubing near the top. For fish in long coiled tubing, multiple drilling operations, segmented cutting, and segmented retrieval are required, resulting in cumbersome construction procedures and low operational efficiency.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein: Figure 1 The schematic diagram illustrates the structure of a continuous tubing cutting and salvage integrated tool according to the present invention. Figure 2 The schematic diagram illustrates the structure of the clamping slips of the integrated tool for continuous tubing cutting and retrieval according to the present invention; Figure 3 The diagram illustrates the structure of the cutting component of a continuous tubing cutting and salvage integrated tool according to the present invention.

[0019] Reference numerals: 1. Upper connector; 2. Cylinder body; 3. Lower connector; 4. Elastic preload; 5. Bearing base; 6. Clamping slip; 7. First cone sleeve; 8. Cutting blade assembly; 9. Second cone sleeve; 10. Shearing limiter; 11. Limiting shoulder; 12. Limiting sleeve; 13. Straightening extension cylinder; 21. Central channel; 22. Slot structure; 31. Second external thread; 32. Second inner hole; 61. First opening slot; 81. Second opening slot; 82. Cutting structure; 91. Protrusion structure; 111. Gap space; 131. First external thread; 132. First inner hole; 821. Cutting tooth; A. Axial direction. Detailed Implementation

[0020] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application. This application can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0021] It should be noted that, in the description of this application, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Furthermore, the terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0023] It should also be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances. All terms used in this application have the same meaning as understood by those skilled in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted with an idealized or highly formalized meaning, unless expressly defined herein.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0025] In well workover operations of oil and gas wells and shale gas horizontal wells, coiled tubing is often used for wellbore flushing and unblocking procedures. During operations, the coiled tubing is prone to sand jamming due to the accumulation of fracturing sand and shale cuttings. If the unblocking operation fails, a "fish" (or "fish-like" tubing string) is formed downhole. A common failure mode is when the lower end of the fish-like tubing is stuck in the well and the upper part of the tubing is suspended freely in the air. To address this type of failure, cutting and retrieval tools need to be run into the well to recover the stuck fish-like tubing.

[0026] Existing coiled tubing cutting and retrieval tools are structurally limited, only allowing insertion of the fish at the top and cutting and retrieving short sections of tubing near the top. When dealing with fish in long coiled tubing (kilometers or more), on-site operations can only employ a multi-stage drilling and retrieval process, using milling tools for segmented cutting and retrieval. This is not only cumbersome and time-consuming, but also inefficient, as repeated drilling increases the risk of secondary downhole failures and well control issues. Therefore, based on practical experience, the inventors designed an integrated coiled tubing cutting and retrieval tool to simplify the process, improve efficiency, and enhance safety during fish retrieval operations.

[0027] like Figure 1As shown, this application provides an integrated tool for cutting and retrieving coiled tubing, comprising: an upper connector 1, a cylinder 2, and a lower connector 3 arranged coaxially. The upper connector 1 is connected to the upper end of the cylinder 2, and the lower connector 3 is connected to the lower end of the cylinder 2. Inside the cylinder 2, along its axial direction A, from top to bottom, are arranged an elastic pre-tightening member 4, a bearing base 5, a clamping slip 6, a first conical sleeve 7, a cutting blade assembly 8, and a second conical sleeve 9. The first conical sleeve 7 is limited and connected to the cylinder 2 by a shearing limiting member 10, and the second conical sleeve 9 is limited and connected to the inner wall of the cylinder 2. The outer wall of the clamping slip 6 is adapted to the inner conical surface of the first conical sleeve 7, and the inner wall of the cutting blade assembly 8 is adapted to the outer conical surface of the second conical sleeve 9. A central channel 21 is formed inside the cylinder 2, allowing the coiled tubing to pass through from the lower connector 3 and axially.

[0028] Specifically, the coiled tubing cutting and retrieval integrated tool provided in this application includes an upper connector 1, a cylinder 2, and a lower connector 3 arranged coaxially. The upper connector 1 is connected to the upper end of the cylinder 2, and the lower connector 3 is connected to the lower end of the cylinder 2. The upper connector 1, the cylinder 2, and the lower connector 3 can all adopt a coaxial rigid connection pipe body fit structure. The coaxial arrangement of the three ensures the coaxiality and downsinking stability of the overall operation, allowing the tool to maintain symmetrical force during the entire process of drill string suspension and descent, downhole sliding, and retrieval operations. This avoids the problems of unilateral well wall friction and downhole swing jamming caused by structural eccentricity, ensuring the overall smooth operation of the tool and providing stable external structural support for the tool to descend a long distance along the outer wall of the coiled tubing to the base of the fish.

[0029] Inside the cylinder 2, along its axial direction A, from top to bottom, are arranged an elastic preload element 4, a bearing base 5, a clamping slip 6, a first cone sleeve 7, a cutting blade assembly 8, and a second cone sleeve 9. The elastic preload element 4 can be a cylindrical helical compression spring, a disc spring assembly, etc., to achieve continuous axial preload pressure, providing stable axial clamping force for the components below. The bearing base 5 can be a ring-shaped rigid support seat, used to support the elastic preload element 4 and bear its preload load, and to support and position the clamping slip 6. The clamping slip 6 and the cutting blade assembly 8 are both radially elastically openable split components, used respectively for continuous tubing clamping and pipe cutting operations. The first cone sleeve 7 and the second cone sleeve 9 are ring-shaped cone assemblies with conical surfaces on their inner and outer walls. The first cone sleeve 7 serves as the power drive component for the clamping slip 6, and the second cone sleeve 9 serves as the power drive component for the cutting blade assembly 8. The aforementioned components are arranged along the axial direction of the cylinder 2, and are driven by two separate sets of cone sleeves for clamping and cutting. In terms of spatial structure, the clamping and cutting actions are separated and operated in sections, avoiding the motion interference defects caused by traditional tools sharing a single cone sleeve, and improving the reliability of downhole cutting and fishing operations from the structural layout level.

[0030] The first cone sleeve 7 is connected to the barrel 2 by a shear limiting member 10. The shear limiting member 10 can be a shear pin, shear screw, or similar device that can withstand a set tensile force before breaking, possessing the basic characteristics of normal limiting and overload shearing. Throughout the process of the tool being lowered to the root of the tubing, the shear limiting member 10 can restrict the axial and circumferential relative displacement between the first cone sleeve 7 and the barrel 2, counteracting the surging phenomena caused by downhole fluid impact, well wall friction, and tool vibration, locking the working position of the first cone sleeve 7, preventing the first cone sleeve 7 from shifting during the lowering stage and driving the clamping slips 6 to retract prematurely, ensuring that the tool can be smoothly guided and lowered using the through-hole central channel 21. When the drill string pulls the barrel 2 upward, and the upward pulling force of the barrel 2 reaches a set threshold, the shear limiting member 10 breaks, and the first cone sleeve 7 moves upward with the barrel 2, squeezing and clamping the slips 6, thereby achieving the clamping action on the coiled tubing.

[0031] The outer wall of the clamping slip 6 is adapted to the inner conical surface of the first conical sleeve 7, forming a conical transmission clamping structure with inclined surfaces. When the drill string is pulled upwards to lift the cylinder 2, the cylinder 2 and the first conical sleeve 7 generate relative axial tension. When this tension reaches the preset shearing load of the shearing limiter 10, the shearing limiter 10 undergoes shear failure, releasing the axial limiting constraint between the first conical sleeve 7 and the cylinder 2. After the shearing limiter 10 breaks under tension, the cylinder 2 drives the first conical sleeve 7 to move upwards synchronously. With the extrusion transmission effect of the conical inclined surface, the clamping slip 6 is driven to produce radially inward contraction deformation, so that the inner wall of the clamping slip 6 tightly fits and bites the outer wall of the coiled tubing, forming a stable and reliable clamping constraint, preventing the coiled tubing from slipping during subsequent cutting operations, and ensuring precise and controllable cutting points.

[0032] The inner wall of the cutting blade assembly 8 is adapted to the outer conical surface of the second conical sleeve 9, forming an independent conical cutting transmission structure. The cutting blade assembly 8 can be a split cutting blade with a cutting edge on the inner side. The second conical sleeve 9 is limited to the inner wall of the cylinder 2, so that the second conical sleeve 9 can complete the lifting and lowering displacement synchronously with the cylinder 2. After the clamping slip 6 clamps and fixes the coiled tubing, the cylinder 2 is continuously lifted. The cutting blade assembly 8 relies on the friction between itself and the outer wall of the coiled tubing to keep it stationary relative to the coiled tubing. An axial relative displacement is formed between the second conical sleeve 9 and the cutting blade assembly 8. The split cutting blade is radially retracted by the conical surface sliding. During the radial retraction process, the cutting edge on the inner side of the blade gradually squeezes and cuts into the wall of the coiled tubing, finally cutting off the coiled tubing. This realizes the step-by-step operation logic of clamping and fixing first, and then cutting independently.

[0033] A central channel 21 is formed on the inner side of the cylinder 2, allowing the coiled tubing to pass through from the lower end connector 3 and axially. The central channel 21 is a circular through-hole that penetrates all the internal parts of the cylinder 2. This circular through-hole allows the tool to form an outer sleeve working structure. Unlike existing cutting and fishing tools that can only work on the top of the fish, this tool can be directly sleeved on the outside of the long suspended coiled tubing when lowering the fish. It is suspended by the drill string and descends smoothly along the outer wall of the coiled tubing to the base of the fish. During the lowering process, the coiled tubing passes through the through-hole, and the drill string and cylinder 2 are all located outside the coiled tubing. This effectively avoids the risk of secondary downhole failure caused by the drill string and cylinder 2 directly hitting the top of the fish during the lowering process.

[0034] The integrated coiled tubing cutting and retrieval tool of this application comprises an upper connector 1, a cylinder 2, and a lower connector 3, all coaxially assembled. Inside the cylinder 2, from top to bottom along the axial direction, are arranged an elastic pre-tightening element 4, a bearing base 5, clamping slips 6, a first cone sleeve 7, a cutting blade assembly 8, and a second cone sleeve 9, forming a complete through-type central channel. The coiled tubing can be inserted into the channel through the lower connector 3 and pass through the entire interior of the tool. The working principle of this tool is as follows: The tool is lowered into the wellbore via the drill string connected to the upper connector 1. During the entire lowering process, the first cone sleeve 7 is axially limited and locked to the cylinder 2 by means of the shearing limiter 10, preventing it from moving upward relative to the cylinder 2. The elastic pre-tightening element 4 continuously outputs pre-tightening force downward, pressing the bearing base 5 and the clamping slips 6, so that the outer wall of the clamping slips 6 is always in close contact with the inner cone surface of the first cone sleeve 7. The clamping slips 6 remain open, the central channel is unobstructed, and the tool can smoothly descend along the outer wall of the coiled tubing to the base of the fish. After the tool is in place, the drill string is pulled upwards, and the barrel 2 moves upwards simultaneously. The shearing limiter 10 breaks after reaching its tensile limit, releasing the constraint of the barrel 2 on it. The first cone sleeve 7 then moves upwards synchronously with the barrel 2. The inner cone surface of the first cone sleeve 7 presses against the clamping slips 6, which radially converge inwards to tightly grip the coiled tubing passing through the central channel, completing the tubing string clamping and fixing. The barrel 2 continues to be pulled upwards, and the second cone sleeve 9 follows the barrel 2, completing its vertical displacement synchronously. The cutting blade assembly 8 remains stationary relative to the coiled tubing due to friction with the outer wall of the coiled tubing. An axial relative displacement occurs between the second cone sleeve 9 and the cutting blade assembly 8. The outer cone surface of the second cone sleeve 9 presses against the cutting blade assembly 8, causing it to radially converge. The inner cutting edge of the cutting blade assembly 8 cuts into the coiled tubing wall, completing the tubing cutting operation. After cutting, the drill string continues to be pulled upwards. Relying on the constraint of the clamping slips 6 gripping the tubing, the cut upper section of the coiled tubing is pulled out of the wellbore along with the entire tool set, completing the integrated cutting and retrieval operation.

[0035] Based on the coordinated operation of the aforementioned structures, the integrated coiled tubing cutting and retrieval tool provided in this application can directly descend to the root position of a long section of coiled tubing where a fish has fallen. At the root of the fish, it completes the entire process of coiled tubing clamping, positioning, and cutting in one go. After cutting, the entire suspended upper section of coiled tubing can be retrieved along with the tool. This effectively solves the shortcomings of existing technologies that require multiple tripping operations, segmented cutting, and segmented retrieval for long-length coiled tubing fish, significantly simplifying on-site well workover procedures, reducing the number of tripping operations, shortening the downhole operation cycle, and lowering overall well workover costs and the probability of complex downhole accidents.

[0036] This tool can be used to repair coiled tubing sand-stuck faults in oil and gas wells. In the field, coiled tubing often gets stuck during sand flushing operations. After unsuccessful attempts to release the stuck tubing, a "fish" (a type of tubing string stuck in the well) forms, typically with the lower end stuck inside the well and the upper part of the tubing string suspended freely. Most working wells are shale gas horizontal wells, with a maximum inclination of up to 49.31°. In high-angle sections, the coiled tubing is easily subjected to external forces and comes into contact with the wellbore, resulting in significant overall friction of the tubing string. Furthermore, after perforation is completed in the working well, the wellbore connects to the formation, and there is pressure at the wellhead after shut-in, creating a complex working environment. The structure and operating logic of this tool are adapted to these field conditions. The working wellbore contains solid media such as fracturing sand and shale cuttings, resulting in significant downhole fluid impact and tool vibration. This tool uses a shear limiter 10 to limit and fix the first cone sleeve 7, preventing premature action of the clamping structure during the running-in process and protecting the intact coiled tubing. The overall coaxial structure of the tool can adapt to the high torque and tubing wall adhesion conditions of highly deviated wells, ensuring stable operation of clamping and cutting actions. At the same time, relying on the axially connected central channel 21 and the independent drive structure of the double cone sleeves, it can be worn outside the coiled tubing and run down to the base of the fish, completing the cutting and retrieval operation in one go, replacing the original multi-stage construction process and reducing the frequency of tripping operations.

[0037] This application provides an integrated tool for cutting and retrieving coiled tubing, comprising: an upper connector 1, a cylinder 2, and a lower connector 3 arranged coaxially. The upper connector 1 is connected to the upper end of the cylinder 2, and the lower connector 3 is connected to the lower end of the cylinder 2. Inside the cylinder 2, along its axial direction A, from top to bottom, are arranged an elastic pre-tightening member 4, a bearing base 5, a clamping slip 6, a first conical sleeve 7, a cutting blade assembly 8, and a second conical sleeve 9. The first conical sleeve 7 is limited and connected to the cylinder 2 by a shearing limiting member 10. The outer wall of the clamping slip 6 is adapted to the inner conical surface of the first conical sleeve 7, and the inner wall of the cutting blade assembly 8 is adapted to the outer conical surface of the second conical sleeve 9. A central channel 21 is formed inside the cylinder 2, allowing the coiled tubing to pass through from the lower connector 3 and axially. This application's tool adopts an integrated structure with the upper connector 1, cylinder 2, and lower connector 3 arranged coaxially. Combined with the axially penetrating central channel 21 within the cylinder 2, the tool can be directly fitted onto the outside of the coiled tubing. Suspended by the drill string, it descends along the outer wall of the coiled tubing to the base of the fish for operation, overcoming the limitation of existing tools that can only insert the fish at the top. Inside the cylinder 2, along the axial direction, are arranged an elastic preload 4, a bearing base 5, clamping slips 6, a first cone sleeve 7, a cutting blade assembly 8, and a second cone sleeve 9. The two independent conical surfaces of the first and second cone sleeves 7 and 9 respectively drive the clamping slips 6 and the cutting blade assembly 8, enabling the clamping and cutting processes to be executed step-by-step. Simultaneously, the first cone sleeve 7 is connected to the cylinder 2 via a shearing limiter 10, locking the position of internal components during descent to prevent malfunctions. The tool can descend directly to the root of the fish in a long section of coiled tubing, completing the entire process of clamping, positioning, and cutting the tubing in one go at the root. After cutting, the entire suspended coiled tubing section can be retrieved along with the tool, eliminating the need for multiple drilling operations and segmented cutting and retrieval, thus simplifying the construction process and effectively improving the retrieval efficiency of fish in long coiled tubing. This application solves the problem that existing coiled tubing cutting and retrieval tools can only insert the fish at the top and cut and retrieve short sections of tubing near the top. For fish in long coiled tubing, multiple drilling operations, segmented cutting, and segmented retrieval are required, resulting in cumbersome construction procedures and low operational efficiency.

[0038] like Figure 1 As shown, in some embodiments, the upper end connector 1 is provided with a limiting shoulder 11 at the end of the second end, and the limiting shoulder 11 and the cylinder 2 have a gap space 111; the upper end of the elastic pretensioner 4 abuts against the upper end connector 1 in the gap space 111, and the lower end of the elastic pretensioner 4 abuts against the bearing base 5.

[0039] Specifically, the upper connector 1 is provided with a limiting shoulder 11 at the second end. The limiting shoulder 11 can reliably limit the axial movement of the elastic pretensioner 4, restricting the upper end of the elastic pretensioner 4 and preventing it from moving upward during lifting and lowering operations, thus ensuring that the installation position of the elastic pretensioner 4 is fixed. The gap space 111 reserved between the limiting shoulder 11 and the cylinder 2 provides reasonable assembly and deformation space for the elastic pretensioner 4, avoiding the problem of unbalanced pretensioning force and component jamming caused by the end face of the cylinder 2 directly squeezing the elastic pretensioner 4.

[0040] The upper end of the elastic preload 4 abuts against the upper connector 1, and the lower end of the elastic preload 4 abuts against the bearing base 5. It can continuously output a uniform axial preload force, so that the bearing base 5 and the clamping slip 6 below always maintain a stable assembly posture. During the lowering operation, the elastic preload 4 continuously presses the bearing base 5, keeping the clamping slip 6 and the first cone sleeve 7 in a close fit, resisting downhole vibration and fluid impact, and preventing internal parts from moving and the slip from rubbing against the tubing. When the shearing limiter 10 cuts, the elastic preload 4 provides a constraint force to maintain the posture of the bearing base 5 and the clamping slip 6, offsetting the instantaneous impact and ensuring smooth and stable cone surface transmission. During the clamping slip 6 clamping the tubing, the cutting operation, and the tubing retrieval stage, the elastic preload 4 restricts the clamping slip 6 from rebounding and loosening through the elastic preload force, ensuring stable and reliable clamping.

[0041] In some embodiments, the outer wall of the support base 5 is provided with multiple guide keys along the circumferential direction, the guide keys extend along the axial direction A, and the inner wall of the cylinder 2 is provided with guide grooves corresponding to the guide keys, and the guide keys are slidably embedded in the guide grooves.

[0042] Specifically, this application utilizes a guide key on the outer wall of the bearing base 5 to slide in conjunction with a guide groove on the inner wall of the cylinder 2. This provides guidance, allowing the bearing base 5 to slide only relative to the cylinder 2 along the axial direction A, restricting the rotation of the bearing base 5 and the clamping slips 6 above it. This ensures precise alignment between the clamping slips 6 and the conical surface of the first conical sleeve 7, preventing misalignment and uneven force distribution. During tool insertion, lifting, clamping, and cutting operations, downhole torque and tubing friction can easily generate torsional forces. The guide key and guide groove can effectively counteract torsional interference, preventing slip wear and unstable engagement, and improving the overall operational stability of the tool under complex well conditions.

[0043] like Figure 2 As shown, in some embodiments, multiple first opening slots 61 are evenly opened circumferentially on the side of the clamping slip 6 facing the first conical sleeve 7. The first opening slots 61 are non-through, and the openings of the first opening slots 61 face the first conical sleeve 7. The outer wall of the clamping slip 6 between adjacent first opening slots 61 is adapted to the conical surface of the inner wall of the first conical sleeve 7.

[0044] Specifically, this application provides that the clamping slip 6 has multiple first opening slots 61 evenly opened circumferentially on the side facing the first conical sleeve 7. The outer wall of the clamping slip 6 can be a conical slope to fit the inner conical surface of the first conical sleeve 7. The first opening slots 61 are non-through structures and their openings face the first conical sleeve 7. The conical slope area between adjacent first opening slots 61 fits snugly against the inner conical surface of the first conical sleeve 7.

[0045] The circumferentially evenly distributed non-through first opening groove 61 enables the clamping slip 6 to have stable radial elastic deformation capability. When the first conical sleeve 7 and the clamping slip 6 undergo axial relative movement, the conical surface compression drives the clamping slip 6 to retract inward. The first opening groove 61 provides sufficient deformation margin to ensure smooth clamping action. The circumferentially evenly distributed opening groove structure design allows for synchronous deformation and balanced stress distribution throughout the slip, which is suitable for the working conditions of coiled tubing adhering to the wall and subjected to eccentric loads in highly deviated wells, effectively avoiding local stress concentration.

[0046] The conical slope of the clamping slip 6 between adjacent first opening slots 61 fully fits the inner conical surface of the first conical sleeve 7, and the force transmission of the conical surface is continuous and uniform, which can stably output clamping force, continuously ensure the clamping effect on the continuous tubing, and effectively prevent the tubing string from slipping or shifting.

[0047] like Figure 3 As shown, in some embodiments, the cutting blade assembly 8 has multiple second opening slots 81 evenly opened circumferentially on the side facing the second conical sleeve 9. The second opening slots 81 are non-through, and the openings of the second opening slots 81 face the second conical sleeve 9. The cutting blade assembly 8 includes multiple cutting structures 82, which are located between adjacent second opening slots 81. The inner wall of the side of the cutting structure 82 facing the second conical sleeve 9 is provided with cutting teeth 821, and the cutting edges of the cutting teeth 821 face the central channel 21.

[0048] Specifically, this application provides a cutting blade assembly 8 with multiple axially extending second opening slots 81 evenly spaced circumferentially on the side facing the second conical sleeve 9. These second opening slots 81 are non-through, providing a reliable radial elastic deformation allowance for the cutting blade assembly 8. The cutting blade assembly 8 consists of multiple cutting structures 82. The openings of the second opening slots 81 face the second conical sleeve 9, and each cutting structure 82 is correspondingly arranged between adjacent second opening slots 81. When the second conical sleeve 9 and the cutting blade assembly 8 undergo axial relative movement, the conical surface extrusion force can drive each cutting structure 82 to synchronously retract inwards. Cutting teeth 821 are provided on the inner wall surface of the cutting structure 82 facing the second conical sleeve 9, with the cutting edges of the cutting teeth 821 facing the tool center channel 21. After the cutting blade assembly 8 is squeezed and retracted by the second conical sleeve 9, the cutting teeth 821 on the inner wall of the cutting structure 82 can evenly press against the outer wall of the continuous tubing, thereby shearing the continuous tubing under the action of cutting force.

[0049] The multiple cutting structures 82 arranged in the circumferential direction have multiple cutting teeth 821 arranged in the circumferential direction, which can simultaneously apply load to the coiled tubing, thereby balancing the force, improving cutting efficiency, and enhancing the stability and regularity of the cutting operation.

[0050] like Figure 1 As shown, in some embodiments, a limiting sleeve 12 is provided between the first cone sleeve 7 and the cutting blade assembly 8, and the outer edge of the limiting sleeve 12 is adapted to be connected to the inner wall of the cylinder 2.

[0051] Specifically, this application adds a limiting sleeve 12 between the first conical sleeve 7, which mates with the clamping slip 6, and the cutting blade assembly 8, establishing an axial separation structure inside the tool to divide the clamping operation area and the cutting operation area, thus achieving spatial partitioning of the clamping and cutting actions within the tool. The outer edge of the limiting sleeve 12 is adapted to the inner wall of the cylinder 2, allowing for a clearance sliding fit. The limiting sleeve 12 can be configured to circumferentially limit and prevent rotation relative to the cylinder while allowing for axial relative sliding. The lower end of the limiting sleeve 12 always abuts against the upper surface of the cutting blade assembly 8, pressing the cutting blade assembly 8 downwards by its own weight. During the cutting operation, the cutting blade assembly 8 remains stationary relative to the coiled tubing due to the friction of the outer wall of the coiled tubing. The limiting sleeve 12 also remains stationary relative to the coiled tubing, providing stable upper-end pressure constraint for the cutting blade assembly 8. When the cylinder 2 drives the second cone sleeve 9 upwards, the outer cone surface of the second cone sleeve 9 presses the cutting blade assembly 8 inwards, smoothly completing the tubing cutting. Simultaneously, the limiting sleeve 12 effectively isolates the first cone sleeve 7 from the cutting blade assembly 8, preventing the clamping slips 6 from axially contacting or interfering with the cutting blade assembly 8 during the clamping operation interacting with the first cone sleeve 7. This ensures that the coiled tubing clamping and positioning process and the tubing cutting process can be completed independently, allowing the two operations to proceed in a step-by-step, orderly manner without interference, improving the overall orderliness and reliability of the tool's operation. During the downhole operation, the limiting sleeve 12 continuously presses down on the cutting blade assembly 8 under its own weight, maintaining the cutting blade assembly 8 in an open state and preventing downhole vibrations from causing the blades to retract accidentally and scratch the coiled tubing.

[0052] like Figure 1 As shown, in some embodiments, the outer wall of the second conical sleeve 9 is provided with a protrusion structure 91, and the inner wall of the cylinder 2 is provided with a slot structure 22. The protrusion structure 91 and the slot structure 22 are adapted to be connected so that the second conical sleeve 9 is limited to be connected inside the cylinder 2.

[0053] Specifically, this application provides a second conical sleeve 9 with an integrally formed protrusion structure 91 on its outer wall, and a corresponding slot structure 22 on the inner wall of the cylinder 2. The second conical sleeve 9 is matched with the protrusion structure 91 and the slot structure 22 through mutual engagement, achieving a limiting assembly with the cylinder 2. After the protrusion structure 91 and the slot structure 22 are engaged, the second conical sleeve 9 can be precisely positioned in both the axial and circumferential directions simultaneously. During the entire downhole cutting and fishing operation, the installation position of the second conical sleeve 9 can be stably maintained, and the coaxial alignment accuracy between the second conical sleeve 9 and the conical surface of the cutting blade assembly 8 can be continuously maintained. This ensures that the axial force generated by the lifting of the cylinder 2 can be uniformly and completely converted into the cutting driving force for the cutting blade assembly 8 to retract inward through the conical surface of the second conical sleeve 9, ensuring that the cutting action is synchronous and the force is uniform, and ensuring that the cutting operation is completed smoothly and efficiently.

[0054] like Figure 1 As shown, in some embodiments, a straightening extension cylinder 13 is provided between the second tapered sleeve 9 and the lower end connector 3; the outer wall of the first end of the straightening extension cylinder 13 in the axial direction A is provided with a first external thread 131, which is used to thread-connect the inner wall of the cylinder body 2; the second end of the straightening extension cylinder 13 in the axial direction A is provided with a first inner hole 132, and the wall of the first inner hole 132 is provided with an internal thread, which is used to thread-connect the lower end connector 3.

[0055] Specifically, this application provides a straightening extension cylinder 13 between the second tapered sleeve 9 and the lower end connector 3. The straightening extension cylinder 13 can increase the support length of the lower section of the tool, form a radially centered straightening constraint on the second tapered sleeve 9, stably maintain the coaxial posture of the second tapered sleeve 9, and ensure that the second tapered sleeve 9 and the cutting blade assembly 8 always maintain a precise tapered surface fit and alignment, so that the axial force of the cylinder 2 lifting can be evenly converted into the cutting power of the cutting blade assembly 8 retracting inward.

[0056] The first end of the straightening extension cylinder 13 in the axial direction A is provided with a first external thread 131 for threaded connection to the inner wall of the cylinder 2, and the second end is provided with a first internal hole 132. The internal thread of the first internal hole 132 is used for threaded connection to the lower end connector 3. The two ends of the straightening extension cylinder 13 are respectively connected to the cylinder 2 and the lower end connector 3 with internal and external threads, connecting the cylinder 2, the second cone sleeve 9, the straightening extension cylinder 13, and the lower end connector 3 into a coaxial integrated structure, extending the lower straightening support range, improving the overall coaxiality of the tool insertion, cutting, and retrieval process, making the cutting blade assembly 8 circumferentially stressed evenly, and the cutting teeth 821 synchronously fit against the outer wall of the continuous tubing, improving the cutting smoothness and cutting efficiency.

[0057] The straightening extension cylinder 13 serves as a transitional connection between the second cone sleeve 9 and the lower end connector 3, effectively separating the installation space between them and allowing for reasonable movement of internal components. The threaded connection facilitates easy assembly and disassembly, enabling on-site disassembly of lower components for maintenance and replacement. It also provides continuous and stable support for the cutting operation of the cutting blade assembly 8, ensuring smooth operation in the well.

[0058] like Figure 1 As shown, in some embodiments, the lower end connector 3 has a second external thread 31 on the outer wall of the first end in the axial direction A, which is used to connect the internal thread; the lower end connector 3 has a second inner hole 32 on the second end in the axial direction A, and the inner diameter of the second inner hole 32 on the side away from the straightening extension cylinder 13 is larger than the inner diameter on the side facing the straightening extension cylinder 13.

[0059] Specifically, the lower end connector 3 is provided with a second external thread 31 on the outer wall of the first end along the axial direction. The second external thread 31 forms a threaded matching connection with the internal thread of the straightening extension cylinder 13, realizing the stable assembly of the lower end connector 3 and the straightening extension cylinder 13. This ensures that the lower end connector 3 and the upper straightening structure are precisely coaxially connected, continuing the overall coaxiality advantage of the tool, providing stable structural support and positioning reference for the lower section of the tool, and ensuring the overall assembly accuracy.

[0060] The lower connector 3 has a second inner hole 32 at its second axial end. The second inner hole 32 adopts a variable diameter structure design, with the inner diameter on the side away from the straightening extension cylinder 13 being larger than the inner diameter on the side facing the straightening extension cylinder 13, thus forming a flared guide structure at the lower end of the lower connector 3. During the tool lowering operation, the flared hole wall can guide the coiled tubing, effectively avoiding coiled tubing deviation and pipe head collisions and jamming, ensuring that the coiled tubing can be quickly and smoothly inserted into the tool's central channel 21, improving the smoothness of tool insertion into the coiled tubing and downward positioning.

[0061] In some embodiments, this application can set the upper connector 1 to match the drill pipe and the cylinder 2 respectively through different forms of internal and external threads at both ends. On the one hand, the reliability of the threaded connection can transmit the suspension force and lifting force of the drill pipe to the whole tool in a complete and stable manner, effectively avoiding the loosening of the connection part during downhole operations. On the other hand, it can ensure that the upper connector 1 and the cylinder 2 are precisely coaxially assembled, strengthening the overall structural rigidity of the tool. At the same time, the threaded connection method is easy to disassemble and assemble, which is convenient for on-site assembly, maintenance and component replacement, ensuring that the tool runs smoothly in the entire operation process such as lowering and lifting.

[0062] In some embodiments, the clamping slip 6 is provided with a friction assembly facing the inner wall of the central channel 21. The friction assembly includes a plurality of friction elements arranged in an array, which are used to conform to the outer wall of the continuous tubing.

[0063] Specifically, this application provides a friction assembly on the inner wall of the clamping slip 6 facing the central channel 21. This friction assembly consists of multiple friction elements arranged in an array. Each friction element can conform to the outer wall of the continuous tubing to achieve friction-enhancing and anti-slip positioning during the clamping process. The friction assembly includes an array of friction elements, which can adopt various anti-slip structures such as axial anti-slip ridges, dotted anti-slip protrusions, arrayed anti-slip teeth, and knurled texture protrusions, as long as they can uniformly conform to the outer wall of the continuous tubing and increase the contact friction coefficient.

[0064] By setting an array of friction elements on the inner wall of the clamping slips 6, the clamping slips 6 can form multiple points of uniform contact with the outer wall of the coiled tubing, increasing the frictional resistance of the contact surface and thus improving the clamping and locking capability of the coiled tubing. Under the conical extrusion action of the first conical sleeve 7, when the clamping slips 6 radially close and tighten around the coiled tubing, the circumferentially and axially arrayed friction elements can be uniformly pressed against the outer wall of the tubing, forming a uniform anti-slip constraint. This can effectively limit the axial movement and circumferential slippage of the coiled tubing relative to the clamping slips 6 during operation. It can stably lock the clamping position of the coiled tubing under complex working conditions such as downhole fluid scouring, mechanical vibration, and alternating cutting loads, ensuring the accuracy and non-offset cutting points of the subsequent cutting tool assembly 8, and improving the regularity of the cutting cut and operational stability. At the same time, the arrayed friction structure is uniformly stressed, without local stress concentration problems, and can be combined with the elastic deformation characteristics of the first opening groove 61 of the clamping slips 6 to improve the overall clamping reliability and operational accuracy of the tool.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A continuous tubing cutting and salvage integrated tool, characterized in that, include: The upper end connector (1), the cylinder (2) and the lower end connector (3) are coaxially arranged. The upper end connector (1) is connected to the upper end of the cylinder (2) and the lower end connector (3) is connected to the lower end of the cylinder (2). The cylinder (2) is arranged from top to bottom along its axial direction (A) with an elastic pre-tightening member (4), a bearing base (5), a clamping slip (6), a first cone sleeve (7), a cutting blade assembly (8), and a second cone sleeve (9); The first cone sleeve (7) is limited to the cylinder (2) by the shearing limiter (10), the second cone sleeve (9) is limited to the inner wall of the cylinder (2), the outer wall of the clamping slip (6) is adapted to the inner wall cone surface of the first cone sleeve (7), and the inner wall of the cutting blade assembly (8) is adapted to the outer wall cone surface of the second cone sleeve (9). The inner side of the cylinder (2) forms a central channel (21) through which a continuous tubing can pass through from the lower end joint (3) and axially extend.

2. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, The upper connector (1) is provided with a limiting shoulder (11) at the second end, and the limiting shoulder (11) and the cylinder (2) have a gap space (111). The upper end of the elastic pretensioner (4) abuts against the upper connector (1) within the gap space (111), and the lower end of the elastic pretensioner (4) abuts against the bearing base (5).

3. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, The outer wall of the bearing base (5) is provided with multiple guide keys along the circumferential direction. The guide keys extend along the axial direction (A). The inner wall of the cylinder (2) is provided with guide grooves corresponding to the guide keys. The guide keys are slidably embedded in the guide grooves.

4. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, The clamping slip (6) has multiple first opening slots (61) evenly opened circumferentially on the side facing the first conical sleeve (7). The first opening slots (61) are non-through and the openings of the first opening slots (61) face the first conical sleeve (7). The outer wall of the clamping slip (6) between adjacent first opening slots (61) is adapted to the inner conical surface of the first conical sleeve (7).

5. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, The cutting blade assembly (8) has multiple second opening slots (81) evenly opened circumferentially on the side facing the second cone sleeve (9). The second opening slots (81) are non-through and the openings of the second opening slots (81) face the second cone sleeve (9). The cutting blade assembly (8) includes multiple cutting structures (82), which are located between adjacent second opening slots (81). The inner wall of the cutting structure (82) facing the second conical sleeve (9) is provided with cutting teeth (821), and the cutting edge of the cutting teeth (821) faces the central channel (21).

6. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, A limiting sleeve (12) is provided between the first cone sleeve (7) and the cutting blade assembly (8), and the outer edge of the limiting sleeve (12) is adapted to be connected to the inner wall of the cylinder (2).

7. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, The outer wall of the second cone sleeve (9) is provided with a protrusion structure (91), and the inner wall of the cylinder (2) is provided with a slot structure (22). The protrusion structure (91) and the slot structure (22) are adapted to be connected so that the second cone sleeve (9) is limited to be connected inside the cylinder (2).

8. The integrated tool for cutting and retrieving coiled tubing according to claim 1, characterized in that, A straightening extension sleeve (13) is provided between the second cone sleeve (9) and the lower end connector (3). The straightening extension cylinder (13) has a first external thread (131) on the outer wall of its first end in the axial direction (A), and the first external thread (131) is used to thread-connect the inner wall of the cylinder body (2); The straightening extension cylinder (13) has a first inner hole (132) at its second end in the axial direction (A). The wall of the first inner hole (132) is provided with an internal thread, which is used to thread-connect the lower end connector (3).

9. The integrated tool for cutting and retrieving coiled tubing according to claim 8, characterized in that, The lower end connector (3) has a second external thread (31) on the outer wall of the first end in the axial direction (A), and the second external thread (31) is used to thread the internal thread. The lower end connector (3) is provided with a second inner hole (32) at its second end in the axial direction (A). The inner diameter of the second inner hole (32) on the side away from the straightening extension cylinder (13) is larger than the inner diameter on the side facing the straightening extension cylinder (13).

10. The integrated tool for cutting and retrieving coiled tubing according to claim 4, characterized in that, The clamping slip (6) is provided with a friction assembly on the inner wall of the central channel (21). The friction assembly includes a plurality of friction elements arranged in an array, which are used to fit against the outer wall of the continuous tubing.

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