Study on residual strength of oil and gas pipeline with corrosion defects under bending load

¹ Safety, Environmental Protection, and Technical Supervision Research Institute of Southwest Oil & Gasfield Branch, China National Petroleum Corporation, Chengdu, Sichuan, China.
² National Engineering Research Center for Pipeline Safety/MOE Key Laboratory of Petroleum Engineering/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum-Beijing, Changping, Beijing, China.

^* Corresponding author: scx1021@petrochina.com.cn

Abstract

The significance of oil and gas pipelines in the exploration and production of oil and gas resources is well-documented. However, these pipelines are subject to a number of challenges that can compromise their integrity and operational efficiency. These challenges include structural defects, geological disasters such as earthquakes, landslides, debris flows, and land subsidence, as well as external forces such as dynamic impact forces, shear forces, extrusion forces, and uneven settlement forces. These defects can be exacerbated, thereby increasing the risk of pipeline failure. To accurately evaluate the pipeline’s bearing capacity and safety, the study developed a nonlinear numerical simulation software called ABAQUS, utilising the Python programming language for analysis. Utilising this model, a systematic study of the dimensional characteristics of corrosion defects (including length, width, and depth) and the influence of pipe material (steel type) on residual strength has been conducted. The results demonstrate that an increase in the length and depth ratios of corrosion defects will result in a substantial decrease in the ultimate rupture pressure of pipelines. The integrity evaluation of oil and gas pipelines has revealed that the width of corrosion defects does not appear to have a discernible impact on residual strength. A thorough analysis of the experimental data reveals that, while the width is influenced by numerous factors, there is no statistically significant variation in the residual strength of corroded defect pipelines with different widths under standard test conditions. If the size and location of corrosion defects remain constant, upgrading the steel grade has been demonstrated to have a substantial impact on the pipeline’s residual strength.