Operation tubing threaded connection structure

Abstract

The invention provides an operation tubing threaded connection structure. The structure is a direct connection type threaded joint, and comprises a tubing of which the tube end is headed and provided with external threads, and a tubing of which the tube end is headed and provided with internal threads, which are screwed. The external threads and the internal threads of the tubings are trapezoid taper threads; a main sealing structure consisting of straight torque shoulders is arranged on the internal threads and the external threads respectively; and the axial interference between the internal threads and the external threads is 2.5 to 10mm. The operation tubing threaded connection structure has the advantages that: by heading the tube ends of the tubings and increasing the length of complete threads, the connecting intensity of a fastening tubing connection structure is improved to 100 percent of the tube intensity. Therefore, local contact stress of the operation tubing in the process of screwing and unscrewing for multiple times is relatively low, a thread gluing phenomenon does not occur, and the looseness resistance of the joint is improved. The operation tubing threaded connection structure has the thread gluing resistance and looseness resistance during screwing and unscrewing for ten or more times, is used for testing, acidification, drilling, borehole operation, production string well completion work of ultra-deep, ultra-high pressure, and high-temperature oil and gas wells, and is used as a small drill stem under special conditions.

Description

technical field [0001] The invention relates to a threaded connection structure of an operation oil pipe. Background technique [0002] The tubing string is formed by connecting single oil well pipes with threads, and the threaded connection part of the tubing string is the weakest link. In the general API standard, the oil pipe adopts the connection form of round thread external thickening or no thickening. These connection forms have certain problems in ensuring the structural integrity and sealing integrity of the pipe string. For example, the thread connection strength of the oil pipe without thickened round thread is only 60% to 80% of the strength of the pipe body. In addition, the acidic hydrogen sulfide contained in the oil and gas will cause slow stress corrosion of the ordinary API oil pipe, resulting in the long-term failure of the oil pipe. Deformation and damage during use. [0003] With the development of the petroleum industry, especially the development of...

AI Technical Summary

Problems solved by technology

Oil pipes with API standard thread connections and conventional special buckles are difficult to meet production needs in many cases

In particular, the corrosion environment in some oilfield blocks is harsh, and conventional tubing cannot withstand repeated acidification and use as drill pipes. The current tubing buckle type's anti-torque and anti-loosening (vibration) capabilities cannot meet the requirements of oilfields.

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