Analysis of expansion performance and parameter sensitivity of solid expandable tubular with thread joint

Abstract

During the expansion process of the threaded joint of the solid expandable tubular (SET), the thread meshing performance and sealing performance will deteriorate, which seriously hinders the development and application of the SET. In this paper, established the force analysis model of different threads in the bulging process and analysis the finite element model of thread. The meshing performance of φ108 mm × 7 mm SET joints made of 20G steel with three types of thread expansion is analyzed. The most suitable parameter range was obtained by optimizing the five thread parameters such as bearing surface angle, guide surface angle, taper, tooth depth and tooth pitch. The results show that the rectangular and trapezoidal threads are deformed seriously during expansion, and the connection of rectangular and trapezoidal threads is easy to cause the seal failure of the SET system; The effects of various thread parameters on the Mises stress and contact pressure distribution were analyzed. It was found that the Mises stress of the first turn of the special skew trapezoidal thread was the highest, and the Mises stress distribution was high at two ends and low at the middle, with the maximum difference of 160 MPa and the contact pressure distribution was high at two ends and low at the middle, with the maximum difference of 200 MPa. The research results provide technical support for obtaining the SET thread with good meshing performance after expansion.