Toothed thread drill stem joint

Abstract

The invention discloses a toothed thread drill stem joint, and belongs to the field of drilling equipment of soil layers or rocks. The joint comprises a female joint and a male joint, wherein the female joint and the male joint have a hollow structure; external threads which extend in the axial direction are arranged on the outer side wall of the male joint, and internal threads which extend in the axial direction are arranged on the inner side wall of the female joint; the female joint and the male joint are screwed integrally by the threads; the internal threads and the external threads are toothed taper threads, and the conical degree of the toothed taper threads is (1:8)-(1:16); tooth crests and tooth roots of the toothed conical threads have an arc-shaped structure, gaps are formed at the matching positions of the tooth crests and the tooth roots, and two sealing surfaces are formed at the matching positions of tooth flanks; and teeth of the toothed taper threads consist of first tooth side angles alpha and second tooth side angles beta, wherein alpha is more than or equal to 20 degrees and is less than or equal to 40 degrees, and beta is more than or equal to 40 degrees and is less than or equal to 50 degrees. By the toothed thread drill stem joint, the accidents of failure of drilling rig threads can be reduced substantially, and the demand of the exploration and development of extradeep wells and large-displacement horizontal wells is met.

Description

technical field [0001] The invention relates to a drill pipe structure used for directional drilling in petroleum, coal, geological mines, hydropower and other industries, belonging to the field of drilling equipment for soil layers or rocks. Background technique [0002] Directional drilling technology has been widely used in my country's petroleum, coal, mining, municipal and other industries. In recent years, with the gradual depletion of easy-to-recovery oil reservoir resources, the world has to focus on the exploration and development of oil and gas resources in areas with more complex geographical and geological conditions. , high-pressure oil and gas wells, extended-reach wells, horizontal wells, and wells containing corrosive media have appeared in large numbers. Drill pipes are an indispensable key tool in the process of oil and gas field exploration and development. These oil and gas wells have put forward higher requirements for their performance and quality. Req...

AI Technical Summary

Problems solved by technology

[0006] 1) The stress concentration and notch effect at the thread root of the API male joint are serious, which is the weak link of fatigue and brittle fracture

[0007] 2) API thread fatigue sensitivity coefficient is high, prone to fatigue or brittle fracture

[0008] 3) The torsional strength and bending fatigue life of API threads are not enough to meet the needs of exploration and development of ultra-deep wells and extended-reach horizontal wells

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