Novel anti-torsion small drill collar joint

Abstract

The invention discloses a novel anti-torsion small drill collar joint which comprises a connection sleeve. An upper joint is arranged inside the upper end of the connection sleeve, a lower joint is arranged inside the lower end of the connection sleeve, the upper joint and the lower joint are connected through a spline and a spline groove, and a first sealing ring is arranged on a contact face; the connection sleeve and the upper joint are connected through a thread, and a second sealing ring is arranged on a contact face; the connection sleeve and the lower joint are connected through a thread, and a third sealing ring is arranged on a contact face. Torque transmission and tension and pressure transmission are separated, so that threaded connection portions do not bear torque and tensionand pressure at the same time any more, torsional strength and tensile strength of a pipe column are enhanced, operation requirements are met, and tool service life is prolonged; operation requirements on forward rotation and reverse rotation in the process of salving a fish can be met, the problem of drill collar thread backoff due to rotation of the pipe column in the process of operation is avoided, and downhole accidents are reduced.

Description

technical field [0001] The invention relates to the technical field of oil and gas drilling and workover, and more specifically relates to a novel torsion-resistant small drill collar joint. Background technique [0002] With the in-depth promotion of water injection polymer flooding development strategy in Bohai Oilfield, the fouling of the central pipe is becoming more and more serious, seriously affecting the normal production and economic benefits of the oilfield. At present, the main salvage method of the central pipe string with scale stuck in the small-sized sand control string is shock and buckle fishing. The salvaged drill tool assembly is mainly divided into 2 categories: ①ф79mm positive thread drill collar + positive thread fishing tool, drill collar joint make-up The maximum torque is only 4KN.m, so the undercut torque that can be tolerated is relatively small, and more depends on the shock to release the card, and the success rate is low. ②The ф79mm undercut dr...

AI Technical Summary

Problems solved by technology

[0002] With the in-depth advancement of the water injection polymer flooding development strategy in the Bohai Oilfield, the fouling of the central pipe is becoming more and more serious, seriously affecting the normal production and economic benefits of the oilfield

At present, the main salvage method of the central pipe string with scale stuck in the small-sized sand control string is shock and buckle fishing. The salvaged drill tool assembly is mainly divided into 2 categories: ①ф79mm positive thread drill collar + positive thread fishing tool, drill collar joint make-up The maximum torque is only 4KN.m, so the undercutting torque that can be tolerated is relatively small, and more depends on the shock to release the jam, and the success rate is low

②The ф79mm undercut drill collar + undercut fishing tool can be undercut and salvaged within the maximum torsion resistance range of the drill collar (<11KN.m). Accidents of fishing tools and drilling tools falling into wells

This method still has disadvantages: firstly, the processing of stress dispersion grooves will aggravate the stress concentration; secondly, once the threads of drill collars with stress dispersion grooves are damaged and need to be repaired, at least a certain distance of threads must be cut off, and the material waste of drill collars is quite large, and further Reduced drill collar life

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