Abstract: The third-party construction damage of oil and gas pipeline is becoming more and more serious. It is necessary to analyze the failure probability of pipelines under third-party construction. So a quantitative failure probability calculation method based on vulnerability theory was proposed. A risk factor evaluation system was set up based on 4M system, the analytic hierarchy process was used to calculate the weights of factors and the weights of expert judgment ability, the expert judgment language was quantized by introducing triangular fuzzy number, and the probability of event risk was obtained by calculating the fuzzy number. Five parameters including external load, pipe diameter, pipe wall thickness, pipeline burial depth and service life were selected to establish vulnerability function from the two aspects of hazard resistance and hazard intensity. The probability of vulnerability was calculated by structural reliability theory. The example analysis shows that this calculation method can effectively calculate the failure probability of pipelines under third-party construction, and provide some technical support for the safety management of oil and gas pipelines.

Key words: oil and gas pipeline, third-party construction, failure probability, hazard, vulnerability