Ultra torsion resistance multi-shoulder full-enclosed taper pipe thread connecting device

Abstract

The invention discloses an ultra torsion resistance multi-shoulder full-enclosed taper pipe thread connecting device. The device comprises an external thread joint, and an internal thread joint in threaded connection with the external thread joint, wherein the internal thread joint main end surface of the internal thread joint is a circular ring surface with a tilt angle; a conical hole is formed in the internal thread end hole part; the external shoulder surface of the external thread joint is a circular ring surface with a tilt angle; the taper pipe thread base part of the external screw thread joint is an elliptical cambered surface; taking the length of the elliptical cross section major semi-axis of the elliptical cambered surface as b and the length of the elliptical cross section short axis of the elliptical cambered surface as 2a, the ratio of the short axis length 2a to the major semi-axis length b is equal to the conical hole taper of the internal thread end hole part; an external thread middle shoulder surface and an internal thread middle shoulder surface are arranged on the internal thread joint and the external thread joint respectively. The device is strong in torque carrying capacity, more reasonable in thread stress distribution, reliable in sealing surface matching, stable in sealed contact elastic deformation, and particularly suitable for the exploration and exploitation of oil-gas deep wells, ultra-deep wells and complex wells.

Description

technical field [0001] The present invention relates to a threaded connection device for petroleum drill pipes used in the exploration and production of oil and gas, in particular to a connection device with a tapered screw thread of an external threaded joint and an internal threaded joint threaded with each other. The threaded connection device is used to transmit the torque of the drill pipe and has a tight sealing performance. Background technique [0002] Oil drill pipe is the main equipment for oil and gas exploration and exploitation. Oil and gas well operations rely on the drill pipe to transmit the torque between the uphole and the downhole, and deliver drilling fluid and mud to the well; when the oil drill pipe is drilling, it mainly bears complex loads such as torsion, compression, bending, vibration, etc. During normal working process, the inside is filled with drilling fluid. The main function of drilling fluid is to carry cuttings from the bottom of the w...

AI Technical Summary

Problems solved by technology

The Chinese patent "Curved Surface Double Shoulder Tool Joint" (patent number: 201220608835.1) is to change the contact surface of the main and auxiliary shoulders of the double shoulder joint from a flat surface to a curved surface, thereby increasing the contact area, although it has a certain impact on the sealing performance. improvement, but its sealing performance still depends on axial load and axial contact stress

These sealing structures all have shortcomings such as small contact surface, great influence on the load condition of the drill pipe, small contact elastic deformation and small contact stress of the sealing mating surface, so that reliable sealing performance cannot be guaranteed, especially in deep well or ultra-deep well operation. ideal

Images