Numerical Simulation Research on the Reliability of Oil/Gas Pipelines Based on Semi-Analytical Method

Abstract

Wall thickness, yield strength, elastic modulus, internal pressure, outer diameter, and other parameters of oil/gas pipelines are within uncertainty and meet certain distributions. These parameters have significant influences on the safety and reliability of pipelines. According to the actual pipeline stress state and the distribution of above parameters, finite element models of safety and reliability of pipeline were established in the paper. The semi-analytical method was introduced to the traditional Monte Carlo method, which greatly reduced the sampling frequency and improved the efficiency of numerical simulation. We took a simulation calculation on the reliability of certain pipeline of the West-East natural gas transmission project using this method, researched the influence of wall thickness, yield strength, elastic modulus, internal pressure, outer diameter and other parameters on the reliability of a pipe, gave the corresponding relationship between the reliability index and ultimate stress. The results show that, introduce the semi-analytical method to Monte Carlo method can effectively improve the simulation efficiency of pipelines’ reliability. The variation coefficient of yield strength, internal pressure, wall thickness and elastic modulus have significant influence on pipelines’ reliability. When the variation coefficient is comparatively large, the overall reliability of pipeline is comparatively low, so we recommend strictly control the deviation of each parameter in actual process of design and operation of pipelines.