Overview of Recent Three-Dimensional, Small-Scale, Mini-Pipe Testing of Carbon Steel Well Tubulars with Internal Pressure, Axial Load, and Internal/External Hydrogen Sulfide Exposure

Abstract

Abstract Mini-pipe testing has been used to expose miniature low-alloy carbon steel pipes to one-sided and two-sided hydrogen sulfide (H2S) combined with high internal pressures (20,000+ psi) and axial loads. This paper explains the types of tests that have been performed and the results that have been observed. One-sided vs two-sided H2S exposure combined with stress gradients across the pipe wall is shown to lead to differences in pipe performance. Test results indicate a substantial increase in pipe material performance when one-sided H2S exposure is taken into account compared with two-sided H2S exposure. Tests of prenotched mini-pipes are introduced, which indicate that a fracture mechanics formula using KISSC from the double-cantilever beam (DCB) test is nonconservative and overpredicts the pipe failure pressure due to sulfide stress cracking. Use of the limiting value, KISSC-Limit, is shown to improve the prediction of pipe cracking failure significantly, making it almost conservative. Use of KISSC...