Coiled tubing salvage accelerator

Abstract

The utility model belongs to the technical field of screw drilling tools, and particularly relates to a coiled tubing salvage accelerator which comprises a transmission assembly and a hydraulic assembly. The transmission assembly comprises a spline mandrel and a spline transmission shell, and the spline mandrel and the spline transmission shell are in transmission connection through spline fit; the hydraulic assembly comprises a sealing shell, a sealing piston, a punching shaft and an inner punching pipe, the punching shaft is sleeved with the sealing piston, the sealing piston is in sliding sealing fit with the sealing shell, and the inner punching pipe is fixedly connected with the punching shaft and extends into the sealing shell. By means of the collaborative design of the transmission assembly and the hydraulic assembly, efficient transmission and enhancement of bidirectional jarring energy in the coiled tubing salvage process are achieved.

Description

Technical Field

[0001] This utility model belongs to the field of screw drilling technology, specifically relating to a continuous tubing retrieval accelerator. Background Technology

[0002] After bridge plug drilling is completed in shale gas wells, debris or tools are often left inside the well, requiring retrieval using coiled tubing. However, coiled tubing operations have inherent drawbacks such as the inability to rotate, limited lifting load, and high friction in the horizontal section, resulting in a low retrieval success rate. Currently, the industry commonly uses tools such as Venturi tubes and strong magnetic retrieval devices to pre-treat the wellbore, and equips the retrieval string with specialized tools such as shock absorbers and low-speed screw motors to assist in fish-top docking. When stuck at the bottom of the well, the main methods of release are repeated lifting / lowering of the tubing string or activation of the shock absorber to generate impact force, but the energy of a single shock absorber is often insufficient to break through complex stuck points.

[0003] While existing technologies can achieve basic shock absorption, they have significant limitations: the impact force of conventional shock absorbers is limited by the elastic deformation capacity of the tubing string itself. When the sticking point strength exceeds the shock absorber's design threshold, additional energy-boosting tools are needed to amplify the impact energy. Currently, there is a lack of efficient shock absorption boosting devices compatible with coiled tubing, making it impossible to provide secondary energy replenishment when the shock absorber fails, resulting in low efficiency in unblocking operations. Therefore, there is an urgent need for an energy-boosting acceleration tool that works in conjunction with the shock absorber to improve the success rate of unblocking through a dynamic energy amplification mechanism. Utility Model Content

[0004] The purpose of this invention is to provide a continuous tubing retrieval accelerator to solve the problems existing in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a continuous tubing retrieval accelerator, comprising a transmission assembly and a hydraulic assembly; the transmission assembly includes a splined mandrel and a splined transmission housing, the splined mandrel and the splined transmission housing being connected by a spline engagement; the hydraulic assembly includes a sealing housing, a sealing piston, a punch shaft and an inner punch tube, the sealing piston being sleeved on the punch shaft and having a sliding sealing engagement with the sealing housing, the inner punch tube being fixedly connected to the punch shaft and extending into the interior of the sealing housing.

[0006] Preferably, the transmission assembly further includes an upper sealing joint and a limiting sealing ring. The upper sealing joint is fixedly connected to the top of the spline mandrel, and the limiting sealing ring is installed inside the spline mandrel and engages with the spline transmission housing. The upper sealing joint is provided with a first high-pressure gasket O-ring and a first ordinary O-ring assembly.

[0007] Preferably, the hydraulic assembly further includes a lower connector, which is fixedly connected to the bottom end of the sealing housing, and the inner punch pipe is connected to the external pipe column through the lower connector; a second ordinary O-ring seal assembly is provided inside the lower connector.

[0008] Preferably, the sealing piston is provided with a second high-pressure gasket O-ring seal group, and the sealing housing and the spline drive housing are sealed and connected by a third ordinary O-ring seal group.

[0009] Preferably, the punch shaft and the spline mandrel are fixedly connected by threads, and a fourth ordinary O-ring is provided inside the punch shaft to achieve sealing with the spline mandrel.

[0010] Preferably, the inner punch tube is provided with a third high-pressure gasket O-ring seal, and the limiting sealing ring is provided with a fifth ordinary O-ring seal.

[0011] The beneficial effects of this utility model are as follows: Through the coordinated design of the transmission assembly and hydraulic assembly, this utility model achieves efficient transmission and enhancement of bidirectional shock energy during coiled tubing retrieval. Its unique spline transmission structure ensures stable torque transmission, and the multi-stage high-pressure gasket sealing ring design of the hydraulic sealing system significantly improves the sealing performance and reliability of the tool under complex working conditions. The integrated structure, requiring no on-site adjustment, allows for quick adaptation to existing retrieval tools. The compact layout balances strength and corrosion resistance, effectively addressing the problems of high friction and difficulty in shock-based unblocking in horizontal sections. When used in conjunction with a shock absorber, the shock force can be amplified through the hydraulic energy storage and release principle, accelerating the unblocking efficiency of the tubing string and significantly improving the retrieval success rate after drilling and grinding bridge plugs in shale gas wells. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0013] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings and preferred embodiments.

[0014] like Figure 1As shown, a coiled tubing retrieval accelerator includes a transmission assembly and a hydraulic assembly. The transmission assembly includes a splined mandrel 1 and a splined transmission housing. The splined mandrel 1 is a key component of the transmission assembly, and its top end is tightly connected to the upper sealing joint 2 via threads, ensuring the stability and sealing of the connection, while facilitating subsequent installation and disassembly. The splined mandrel 1 has a position for installing a limiting sealing ring 5, which is fixed by a snap ring or a stepped structure to prevent displacement during operation. An eighth ordinary O-ring seal 19 is installed on the inner wall of the limiting sealing ring 5. This seal tightly fits the surface of the splined mandrel 1, effectively preventing fluid leakage and providing a certain buffering effect. The outer side of the splined mandrel 1 is splinedly engaged with the splined transmission housing 4. This connection method can efficiently transmit torque and ensure stable power transmission.

[0015] The upper sealing joint 2 is internally fitted with a first high-pressure gasket O-ring 22, a first ordinary O-ring 20, and a second ordinary O-ring 21, which are located in different sealing grooves, forming a three-stage sealing structure. This structure effectively isolates external fluids, ensures internal sealing, and prevents high-pressure liquid from leaking into the external environment.

[0016] The sealing plug 3 is installed at a specific hole in the upper sealing joint 2, usually using a threaded connection. Its main function is to seal the hole, preventing hydraulic oil or other media from leaking out. The limiting sealing ring 5, in addition to achieving a sealing function through the eighth ordinary O-ring 19, also restricts the axial displacement of the spline drive housing 4, ensuring that the movement range of the spline drive housing 4 on the spline spindle 1 is within a reasonable range, thus guaranteeing the stability of the entire transmission system. The spline drive housing 4 is fitted onto the outside of the spline spindle 1, achieving torque transmission through spline engagement. Its bottom end is threaded to the top end of the sealing housing 6, and the connection is equipped with a fifth ordinary O-ring 17 and a sixth ordinary O-ring 18, effectively preventing hydraulic oil leakage from the connection and ensuring the normal operation of the hydraulic system. The top end of the punch 7 is fixedly connected to the spline spindle 1 by threads, and a seventh ordinary O-ring 16 is installed at the connection point to prevent hydraulic oil leakage from the connection between the punch 7 and the spline spindle 1, ensuring the sealing performance of the hydraulic system. The sealing piston 8 is fitted in the middle of the punch shaft 7, and a good sliding seal is required between it and the inner wall of the sealing housing 6. To this end, a second high-pressure shim O-ring 14 and a third high-pressure shim O-ring 15 are installed on the surface of the sealing piston 8. These two high-pressure shim O-rings can withstand high pressure, ensuring that no leakage occurs between the sealing piston 8 and the sealing housing 6 during hydraulic system operation, guaranteeing normal hydraulic oil flow and pressure transmission. The bottom end of the inner punch tube 9 is fixedly connected to the punch shaft 7, and the top end extends into the interior of the sealing housing 6. A fourth high-pressure shim O-ring 11 is installed on the surface of the inner punch tube 9. This ring fits tightly against the inner wall of the sealing housing 6, forming a high-pressure seal to prevent high-pressure hydraulic oil from leaking from the gap between the inner punch tube 9 and the sealing housing 6, ensuring the high-pressure stability of the hydraulic system. The sealing housing 6 provides a relatively enclosed working space for the hydraulic system, and its bottom end is connected to the lower connector 10 via threads. The lower connector 10 is equipped with a third common O-ring 12 and a fourth common O-ring 13, which effectively prevents fluid leakage from the connection between the lower connector 10 and the sealing housing 6, while providing a reliable seal for connecting to the external tubing string. The lower connector 10 is mainly used to connect to the external tubing string. The third common O-ring 12 and the fourth common O-ring 13 inside it ensure the sealing of the connection with the external tubing string, prevent fluid leakage at the connection point, and ensure the normal connection and operation of the entire coiled tubing retrieval accelerator with external equipment.

[0017] When the coiled tubing retrieval accelerator encounters resistance during its descent into the well, the operator can lift or lower the tubing string to allow the sealing piston 8 to slide on the punch shaft 7, compressing the hydraulic oil inside the sealing housing 6 and increasing the hydraulic oil pressure. The increased hydraulic pressure is then transmitted to the external tubing string through the inner punch tube 9, providing power for the retrieval operation.

[0018] Throughout the process, the spline structure between the spline drive housing 4 and the spline spindle 1 ensures stable torque transmission. When the shock absorber is activated, the hydraulic energy stored in the sealed housing 6 is released instantly, applying bidirectional shock force to the tubing string through the punch shaft 7 and the inner punch tube 9, effectively helping to relieve the sticking problem encountered by the tubing string downhole.

[0019] The design of multi-stage sealing rings is crucial throughout the entire operation. They effectively prevent high-pressure fluid leakage, ensure good sealing and reliability of the tool under complex downhole conditions, and guarantee the normal operation of the coiled tubing retrieval accelerator and the smooth progress of retrieval operations.

[0020] It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A coiled tubing fishing accelerator, characterized by, Including transmission assembly and hydraulic assembly; The transmission assembly includes spline spindle (1) and spline transmission shell (4), spline spindle (1) is connected with spline transmission shell (4) by spline fit transmission;The hydraulic assembly includes sealing shell (6), sealing piston (8), impact shaft (7) and inner impact pipe (9), the sealing piston (8) is set on impact shaft (7) and is in sliding sealing fit with sealing shell (6), the inner impact pipe (9) is fixedly connected with impact shaft (7) and extends to the inside of sealing shell (6).

2. The coiled tubing fishing accelerator of claim 1, wherein, The transmission assembly further includes upper sealing joint (2) and limiting sealing ring (5), the upper sealing joint (2) is fixedly connected to the top end of spline spindle (1), and the limiting sealing ring (5) is installed inside spline spindle (1) and is in limiting fit with spline transmission shell (4);The first high-pressure gasket O-shaped sealing ring (22), the first ordinary O-shaped sealing ring (20) and the second ordinary O-shaped sealing ring (21) are arranged in the upper sealing joint (2).

3. The coiled tubing fishing accelerator of claim 1, wherein, The hydraulic assembly further includes lower joint (10), the lower joint (10) is fixedly connected to the bottom end of sealing shell (6), and the inner impact pipe (9) is connected with external pipe column through lower joint (10);The third ordinary O-shaped sealing ring (12) and the fourth ordinary O-shaped sealing ring (13) are arranged in the lower joint (10).

4. The coiled tubing fishing accelerator of claim 1, wherein, The second high-pressure gasket O-shaped sealing ring (14) and the third high-pressure gasket O-shaped sealing ring (15) are arranged on the sealing piston (8), and the sealing shell (6) and the spline transmission shell (4) are sealedly connected through the fifth ordinary O-shaped sealing ring (17) and the sixth ordinary O-shaped sealing ring (18).

5. The coiled tubing fishing accelerator of claim 1, wherein, The impact shaft (7) is fixedly connected with spline spindle (1) by thread, and the seventh ordinary O-shaped sealing ring (16) is arranged in the impact shaft (7) to realize sealing with spline spindle (1).

6. The coiled tubing fishing accelerator of claim 1, wherein, The fourth high-pressure gasket O-shaped sealing ring (11) is arranged on the inner impact pipe (9), and the eighth ordinary O-shaped sealing ring (19) is arranged on the limiting sealing ring (5).

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