Coiled tubing connector

Abstract

The invention relates to a coiled tubing connector. The coiled tubing connector includes an upper joint, a middle joint and a lower joint, the upper joint, the middle joint and the lower joint are hollow and coaxially arranged, the upper part of the upper joint is provided with the upper connection part of the upper joint, and the lower part of the lower joint is provided with the lower connectionpart of the lower joint; and the middle joint includes an outer shell part and a core pipe part, the upper part of the outer shell part can be connected with the upper joint in a sealed mode, and theupper part of the core pipe part can be rotated and penetrates through the outer shell part in locked, fixed and sealed modes, the lower part of the core pipe part is connected with the lower joint in a sealed mode, the internal cavities of the upper joint, the core pipe part and the lower joint are arranged to be the same in diameter size, and the upper joint, the core pipe part and the lower joint are arranged to be the same in outer diameter size According to the coiled tubing connector, a free pair used for middle transition rotation is provided for a coiled oil pipe which cannot rotate,screwing-on and screwing-off in a rotated mode, are convenient to conduct when the coiled oil pipe is connected with another coiled oil pipe, in the meantime, fixing and fastening can be conducted soas to realize torque transmission, and hence, the coiled tubing can be used for the completion of various downhole operations such as well drilling, completion, logging and repairing of deep well andextradeep well.

Description

technical field [0001] The invention relates to the field of petroleum and natural gas engineering, in particular to a coiled tubing connector which can be connected in rotation and can be locked and fixed to transmit torque. Background technique [0002] Coiled tubing has a wide range of uses: it can be used to clean pipelines, flush sand plugs, wax removal, selective acidification, gas lift production, cement squeeze plugging, well killing, negative pressure perforating, well testing, displacement of drilling fluid, large deviated High-degree well logging, horizontal well logging, well completion, fishing, tripping and setting expansion splitter, drilling plug, grinding and dropping fish, permanent installation as production pipe, bottom hole camera, slim hole drilling, secondary drilling and deepening drilling, casing window sidetracking, tubing subsidy, etc., can be used for horizontal well drilling, cased well drilling, open hole drilling, deepening drilling, slim hole dr...

AI Technical Summary

Problems solved by technology

[0003] However, there are problems that need to be solved urgently in the downhole operation technology of coiled tubing: generally, the diameter of the coiled tubing used for operation is relatively small, and the water hole in the coiled tubing is even smaller, and a large part of the coiled tubing is coiled on the drum. The circulation pressure loss of the water hole is relatively large, especially on the drum, due to the influence of the secondary vortex, the circulation pressure loss is even greater, and most of the circulation pressure loss is consumed on the coiled tubing drum, which seriously affects the distribution of water power for coiled tubing downhole operations

[0006] (1) Screw-type coiled tubing connectors generally use screws to lock and connect the outer wall of the coiled tubing to realize the transmission of torque and tension. The compression force is limited, and the transmitted torque and tensile stress are small. It is only suitable for the connection of coiled tubing and downhole tools in operations such as well logging and gas lift where the force of the downhole string is not large. It is not suitable for those with large force requirements. Coiled tubing drilling operations; at the same time, most screw connectors need to rotate around the axial direction during the connection process to realize the buckle connection. When the coiled tubing is connected to the coiled tubing, the two connected coiled tubing cannot rotate. The device is also not suitable for the connection between coiled tubing and coiled tubing

[0007] (2) Slip-type coiled tubing connectors are generally locked by adding slips on the outer wall. Also due to the pressure deformation of the coiled tubing, the locking force of the slips is limited, and the torque and tensile stress transmitted after connection Smaller, it is only suitable for the connection of coiled tubing and downhole tools in operations such as well logging and gas lift where the force of the downhole string is not large. At the same time, most slip connectors need to be rotated around the axial direction during the connection process Realize the tight connection of slips. When the coiled tubing is connected with the coiled tubing, the two connected coiled tubing cannot rotate, so the slip type coiled tubing connector is not suitable for the connection between the coiled tubing and the coiled tubing.

[0008] (3) Groove ring-pressed coiled tubing connectors mostly press the water eye in the coiled tubing into the supporting slips with annular grooves, and use the clamping effect of the annular grooves to realize the connection with the coiled tubing. The device does not need to be rotated when connected, and can be used for the connection between coiled tubing and coiled tubing, and can also be used for the connection between coiled tubing and downhole tools. However, because the groove ring pressing type mostly relies on the friction generated by the inner wall expansion and compression The transmission of torque and pulling force, instead of pressurizing the inner and outer walls at the same time, considering the reduction effect of the expansion and deformation of the coiled tubing on the pulling force and torque, the grooved coiled tubing connector is only suitable for logging and gas wells with small torque and pulling force The connection between coiled tubing and downhole tools or coiled tubing for lifting and other operations, but it is not suitable for coiled tubing drilling operations that require relatively large tension and torque

Currently on the market, there is no domestic coiled tubing joint that provides a rotary connection for the coiled tubing connector and is used for drilling with a large tensile and compressive stress and high torque.

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