STRENGTH PROPERTIES ANALYSIS OF J55 TUBING PREMIUM CONNECTION

Abstract

Objective Analysis of torque screwing performance and four kinds of ultimate failure stress distribution of the J55 high strength no shoulder tubing premium connection,the inner wall of the tubing connection is smooth and alignment in favor of the eccentric wear of pumping rod. Methods Establish theoretical model for the specifications of 73. 02 × 5. 51 mm J55 high strength special thread joint pipe,stress analysis、four kinds of limit load failure（ stretched to failure、compressed to failure、internal pressure to failure、external pressure to failure） stress distribution and the theoretical limit failure load analysis,stress distribution and rationality analysis of threaded joints under various conditions of the whole stress,the stress analysis of sealing ring contact. Results The finite element analysis shows that the stress distribution of the oil pipe torque screwing was reasonable,sealing rings were kept in high contact stress,and joints on the top end of the face as a assisting seal has been maintained at high pressure,the main seal and end assisting seal of Teflon seal ring were work together,the joints shows good sealing ability. The failure of four kinds of limit load（ respectively as 408. 9 k N、584. 1 k N、84. 0 MPa、87. 0 MPa） are better than the strength requirements of the round thread in the API standard. The stress distribution of the threaded joint is reasonable. Conclusion The middle diameter of the threaded joint during the torque screwing can be reduced appropriately,in order to improve the performance of anti adhesion; in four kinds of limit load failure mode,the performance of high strength and special screw thread joint is good,accord with strength requirement of the specification of round thread in the API standard; the main seal and auxiliary seal effect of sealing ring is good