Self-adaptive diameter-variable centralizer

Abstract

The invention relates to a self-adaptive diameter-variable centralizer used in the field of oil and gas well engineering. The problems that a drill stem is poor in centering degree and large in friction resistance are solved. According to the technical scheme, the upper end of a stator casing is in threaded connection with the lower end of an upper joint, and the lower end of the stator casing isin threaded connection with the upper end of a connecting cylinder; a rubber stator is fixed in an inner cavity of the stator casing; a spiral rotor is arranged in an inner cavity of the rubber stator, a bearing a is mounted at the upper end of the outer circle of the spiral rotor; a transmission lead screw is arranged in an inner cavity of the connecting cylinder and flexibly rotates in the innercavity of the connecting cylinder; the upper end of a lower joint is in threaded connection with the lower end of the connecting cylinder; and the rolling wheels are hinged to the lower ends of supporting arms a, and the rolling wheels are hinged to the lower ends of supporting arms b. The self-adaptive diameter-variable centralizer can realize an effective diameter-variable function underground,the rolling wheels are completely attached to the well wall, and the centering degree of the drill stem is good; and the rolling wheels and the well wall do pure rolling, axial friction force betweenthe drill stem and the well wall is small, and the drill stem is convenient to feed.

Description

technical field [0001] The invention relates to a centralizer with self-adaptive variable diameter used in the field of oil and gas well engineering. Background technique [0002] In the drilling operations of horizontal wells, directional wells, and extended-reach wells in oil and gas fields, due to the gravity of the drill string, the drill string is easy to deviate in the wellbore or even lie on the well wall, with poor centering and difficult orientation, which seriously affects drilling quality. The traditional rigid centralizer has a large outer diameter, which is not variable, and it is difficult to run in, especially in the corner section with a small curvature radius in horizontal wells and extended-reach wells. However, the traditional elastic centralizer is full of eyes in the initial state. During the process of running into the downhole, the elastic sheet and the well wall continue to rub against each other. The running friction is large, the elastic sheet is e...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is: in order to solve the problem of poor centering of the drill string and large frictional resistance of the drill string, a centralizer with self-adaptive variable diameter is provided.

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