Looseness-proof high-air tightness connecting structure with threaded sleeves

Abstract

The invention relates to a looseness-proof high-air tightness connecting structure with threaded sleeves, comprising a factory end sleeve, an oil field end sleeve and a connecting hoop which are screwed into a whole through screw threads, wherein one end of the connecting hoop is firmly connected with the sleeves, and the other end of the connecting hoop is screwed in internal screw threads of the connecting hoop through the mode of torque defining so that a pressurized interference sealing butting structure can be formed by the butting end faces of the sleeves at both ends or be formed through sealing steps of the connecting hoop or a middle sheath; and the connecting strength between the factory end sleeve and the connecting hoop as well as the connecting strength between the oil field end sleeve and the connecting hoop are ensured through threaded connection, and seal performance among the factory end sleeve, the oil field end sleeve and the connecting hoop is ensured by the end face pressurized interference sealing butting structure. The end face interference sealing is ensured by using a torque wrench. The invention ensures the connecting strength among the factory end sleeve, the oil field end sleeve and the connecting hoop, and guarantees that high-sealing end face interference sealing butt joint can be formed between the oil field end sleeve and the factory end sleeve.

Description

Technical field: [0001] The invention relates to a casing screw connection structure used in oil and natural gas exploitation drilling, in particular to a connection structure of a high airtight thread casing. Background technique: [0002] High-strength, high-air-tight casing joints must be used in oil and natural gas drilling. Hou Yi of Tianjin disclosed a "High-air-tight partial trapezoidal threaded casing connection structure" in ZL96106583.4. The two ends of the pipe are made with tapered partial trapezoidal external threads, and the two ends of the coupling are made with tapered partial trapezoidal internal threads. The wall thickness end faces at both ends of the casing are arc-shaped surfaces. If the gap is "△", the pipe ends of the two casings are pressed against each other, and the pipe wall produces weak plastic deformation in the axial direction, forming a metal-to-metal sealing surface. The patent also discloses its three optimized structures, that is, the part...

AI Technical Summary

Problems solved by technology

[0003] First, although there is a standard line on the tight end of the oil field of the coupling, and a marking line on the casing at the oil field end, in actual use, it is often necessary to disassemble and assemble between the casing at the oil field end and the coupling, and the standard line On the other hand, the radius of curvature of the butt end faces of the factory casing and the oil field casing will inevitably undergo plastic deformation after repeated disassembly and assembly, so that the axial direction of the originally designed casing threaded connection The interference "△" gradually decreases. It is very inaccurate to judge whether the two are fastened in place based on the original standard line and the marking line. less than sealing requirements

[0004] Second, in order to overcome the above defects, people usually use the method of screwing the casing at the oilfield end to overcome the defect that may cause the end faces of the two casings to be unsealed. There is an interference contact between the contact end faces, and when the casing at the oil field end is rotated, it will cause the casing at the factory end to reverse, thereby causing looseness between the casing at the factory end and the coupling, thereby reducing the connection strength, which is very dangerous Defects, in severe cases, will cause the oil pipe to be separated from the coupling, and the consequences will be disastrous

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