Research On Quantitative Sharp Disaster Risk Evaluation Of Onshore Oil-Gas Pipeline

Now, many onshore oil-gas pipelines in service have come into the aging period in our country. As the impact of service time and environment, pipeline defect deteriorates constantly and failure probability increases year by year, which affects the safe operation of pipelines seriously. Because of the transmission medium which is flammable, explosive and easy diffusion, pipeline failure will cause a major threat to personal safety and environment, even cause huge losses to the national economy. Therefore, it will be of important significance to conduct risk assessment of onshore oil and gas pipelines.Because of innate similarity in construction methods and reasoning mechanism between Bayesian network analysis and fault tree analysis, the paper creates Bayesian networks analysis model based on fault tree, by using the mapping relationships between the nodes and event, coupling strength and logic gates. The model solves the problem that traditional probability analysis method can’t describe the event polymorphism and the logic uncertainty, by entering the corresponding CPT to actual project value, so that the failure probability calculation is more practical. And with Hugin Lite software, probability analysis and sensitivity analysis of complex Bayesian network are finished. In the pipeline failure consequences analysis, the leakage rate of oil-gas and the diffusion models after leakage are introduced. It also creates calculation model respectively for such three kinds of sharp disaster consequences as pool fire, jet fire, and vapor cloud explosion. With the calculation model, the influence sphere of thermal radiation of fire and shock wave of vapor cloud explosion are determined, and lethality rate is derived on this basis. In addition, it conducts instance analysis for three kinds of sharp disaster consequences to verify the reliability and the actual operability of model. Based on the proposed calculation models of failure probability and accident consequences, the calculation model of individual risk and social risk is established by TZS. Finally, combined with specific conditions in China and risk determined principles, it proposes the acceptance criteria of oil-gas pipeline risk which is suitable for China.In summary, the paper systematically researches the onshore oil-gas pipeline model of failure probability and sharp disaster consequences. And quantitative evaluation method of individual risk and social risk is proposed on this basis. A complete database has not been established because of a late start of domestic quantitative risk assessment, due to which and author’s limited research level, the data in the paper is from multiple reference literature, so that the calculation results have a certain authenticity but does not have a full sense of universal guidance.