Direct-connection drill rod for limiting conditions

Abstract

The invention relates to a direct-connection drill rod for limiting conditions. The direct-connection drill rod comprises a male connector and a female connector, wherein an outer pipe section is arranged on the outer sides of threads of the male connector; an annular groove is formed between the outer pipe section and a threaded section of the male connector; the female connector is provided withan inserting section; the inserting section is inserted into the annular groove of the male connector in a matched manner; a male connector main shoulder is arranged at a tip of the outer pipe section; a male connector main auxiliary shoulder is arranged on the bottom surface of the annular groove; a male connector auxiliary shoulder is arranged at the small end of the male connector; a female connector main shoulder is arranged on the bottom surface of the inserting section of the female connector; a female connector main auxiliary shoulder is arranged at the large end of the female connector; a female connector auxiliary shoulder is arranged on the bottom surface of the threaded small end of the female connector; the male connector main shoulder and the female connector main shoulder form a main sealing surface; the male connector main auxiliary shoulder and the female connector main auxiliary shoulder form a main auxiliary sealing surface; and the male connector auxiliary shoulderand the female connector auxiliary shoulder form an auxiliary sealing surface. According to the direct-connection drill rod, the sealing performance of the connectors can be obviously improved, and the problem of thread stress concentration of a conventional structure is relieved; and thread stress is relatively uniformly distributed, and capability of resisting large bending deformation and torsional deformation of the drill rod is improved.

Description

technical field [0001] The invention relates to a drilling device, in particular to a direct-connected drill pipe joint used in extreme working conditions. Background technique [0002] The drill pipe is used as the link connecting the surface to the bottom of the well during the drilling process, and plays the role of mud transportation, torque transmission and sealing gasket. The stress state of the drill pipe is complex, and the failure of the drill pipe has become one of the main downhole accidents, especially the drill pipe joint, which is the main component of the drill pipe failure. In recent years, with the rise of ultra-deep scientific drilling and deep-sea scientific drilling, extreme working conditions such as high temperature, high pressure, high stress, and no riser have put forward higher requirements on the performance of drill pipes. Conventional drill pipes can no longer meet the severe working conditions. Due to the requirements of the conditions, accident...

AI Technical Summary

Problems solved by technology

In recent years, with the rise of ultra-deep scientific drilling and deep-sea scientific drilling, extreme working conditions such as high temperature, high pressure, high stress, and no riser have put forward higher requirements on the performance of drill pipes. Conventional drill pipes can no longer meet the severe working conditions. Due to the requirements of the conditions, accidents such as joint box expansion, shoulder seal failure, thread cross-threading and root fracture occur frequently, especially for drill pipes working under high pressure and large bending moment (without riser). Performance has become the bottleneck restricting the improvement of drill pipe performance

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