Safety joint

Abstract

The invention provides a safety joint. The safety joint comprises an upper joint, a connecting sleeve, a positioning sliding sleeve, a lower joint, a first sealing part and a second sealing part. Thelower portion of the upper joint is connected with the upper portion of the connecting sleeve; the lower portion of the connecting sleeve is connected with the upper portion of the lower joint; the positioning sliding sleeve is fixed in the connecting sleeve; the first sealing part is arranged on the contact face of the upper portion of the connecting sleeve and the upper portion of the positioning sliding sleeve; the second sealing part is arranged on the contact face of the lower portion of the connecting sleeve and the lower portion of the positioning sliding sleeve; the first sealing partcomprises an upper sealing ring and a first combined sealing ring; and the second sealing part comprises a lower sealing ring and a second combined sealing ring. According to the safety joint, the sealing parts are arranged to comprise the sealing rings and the combined sealing rings; the combined sealing rings play a main sealing role, and the sealing rings play an auxiliary sealing role, therebyguaranteeing that the sealing parts can work stably in the high-temperature environment; and therefore the safety joint can have a good sealing role under the high-temperature and low-temperature working conditions and can be widely applied to the field of heavy oil thermal recovery.

Description

technical field [0001] The present application relates to the field of oil exploitation, in particular, to a safety joint. Background technique [0002] In the process of oil and gas production, the safety joint is a safety tool for disengagement and docking of the downhole pipe string. Its function is to release the stuck pipe string from the safety joint when a fault occurs downhole or the pipe string is jammed. , so as to reduce the operation risk, reduce the workload and improve the safety of the operation. Thermal oil recovery is currently the most effective heavy oil recovery technology, which involves high temperature and high pressure working conditions, steam injection pressure can reach 21MPa, and steam injection temperature can reach 350°C. Therefore, the use of safety joints in thermal recovery wells requires good sealing performance throughout the injection-production process, which requires the sealing mechanism of the safety joint to be able to withstand high...

AI Technical Summary

Problems solved by technology

[0003] At present, the commonly used safety joints mainly include the shear nail type and the buckle type. The conventional shear nail type safety joints only rely on the shear nails to connect the upper and lower joints. Accidents: zigzag reverse buckle safety joints, thread matching requires a certain degree of pre-tightening, and it is difficult to disengage

Moreover, most of the existing safety joints, no matter they are buckle type or shear nail type, are designed for cold mining wells. The inner seals are made of rubber sealing rings, and the temperature resistance generally does not exceed 150°C. It will fail under high temperature conditions and cannot be used. Meet the high and low temperature alternating working conditions of thermal recovery wells, thereby affecting steam injection and production

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