Research on the expansion and failure of solid expandable tubular based on the Johnson-Cook failure model

Abstract

The exploration and development of deep unconventional oil and gas wells pose new challenges to the solid expandable tubular (SET) technology. Determining the expansion limit of the SET is of great significance for reducing costs, improving design efficiency and ensuring construction safety. Therefore, a new method for studying and predicting the expansion limit of the SET is proposed. Based on the Johnson-Cook constitutive model and failure model, combined with the expansion test of the SET and the material tensile test, a numerical simulation of the expansion failure behavior of the SET were conducted. The influence of sensitive parameters such as expansion speed, pipe material, ovality, wall thickness, and wall thickness unevenness on the limit expansion rate of SET were systematically analyzed. The research results show that: 1) Either too fast or too slow an expansion speed will reduce the expansion limit of SET. The recommended expansion speed for 20G is 1 m/s 2) The limit expansion ratios of 20G, 316L, and Al (2024) pipe materials are 27 %, 51 %, and 22.5 % respectively. 3) For every 1 % increase in the ovality of the pipe, the limit expansion rate of the SET decreases by approximately 0.26 %. For every 1 mm increase in the wall thickness of the pipe, the limit expansion rate of the SET increases by approximately 0.65 %. For every 1 % increase in the wall thickness unevenness of the pipe, the limit expansion rate of the SET decreases by approximately 2.91 %. The results can provide theoretical guidance for the design and construction of the SET.