Elbow-type dual-thrust hydraulic centralizer

Abstract

The invention provides an elbow-type dual-thrust hydraulic centralizer. The elbow-type dual-thrust hydraulic centralizer comprises a hydraulic thrust system and a centering system, wherein the hydraulic thrust system comprises a main body, hydraulic cylinders and a retaining system; the hydraulic cylinders are arranged on the main body; a piston is arranged in each hydraulic cylinder; the hydraulic cylinders and the pistons act on the centering system through in-pipe pressure building to realize centering; the retaining system can realize permanent centering after in-pipe pressure relief; the centering system comprises a push ring, a positioning block and at least four groups of elbows uniformly distributed on the circumference of the main body; the push ring is connected with the pistons; the positioning block is fixed to the middle of the main body; one end of each elbow is fixed on the push ring, and the other end of each elbow is fixed on the positioning block; an included angle is formed between each elbow and the main body; and the centering system can be started up by an extremely small starting force. The bidirectional hydraulic system ensures no axial displacement of the centering system; owing to the unique pre-bending structural design, the starting force of the centering system becomes smaller; and the elbow-type dual-thrust hydraulic centralizer is suitable for centering casings of both horizontal wells and highly-deviated wells.

Description

technical field [0001] The invention belongs to the field of hydraulic centralizers, in particular to an elbow-bending double-push hydraulic centralizer. Background technique [0002] In the prior art, commonly used casing centralizers mainly include elastic centralizers and rigid centralizers. In horizontal wells and highly deviated wells, due to the heavy pipe string, the elastic steel sheet of the elastic centralizer is easily deformed, and the centralizing effect is not good. Rigid centralizers (including roller centralizers) increase the outer diameter of the entire pipe string, making it difficult to run the pipe string. If the wellbore conditions are not ideal, it is easy to cause obstruction. In horizontal wells and high-inclination wells, since the centralizer is always attached to the well wall during the running process and scrapes the wellbore, it is easy to cause mud and sand to accumulate, making it impossible to start the pump. In the "sugar gourd" and "big...

AI Technical Summary

Problems solved by technology

In horizontal wells and highly deviated wells, due to the heavy pipe string, the elastic steel sheet of the elastic centralizer is easily deformed, and the centralizing effect is not good

Rigid centralizers (including roller centralizers) increase the outer diameter of the entire pipe string, making it difficult to run the pipe string

If the wellbore conditions are not ideal, it is easy to cause obstruction

In horizontal wells and high-inclination wells, since the centralizer is always attached to the well wall during the running process and scrapes the wellbore, it is easy to cause mud and sand to accumulate, making it impossible to start the pump

In the "sugar gourd" and "big belly" well sections, these two centralizers are even more unable to play a centralizing role

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