Risk Evaluation Method Based On Fault Tree Analysis In Gas Storage Well

Gas storage well, a vertical tubular pressure equipment to storage gas, was put into used in1994. Gas storage wells are now widely used in compressed natural gas filling stations.Meanwhile, gas storage wells are also facing many security risks and it is important to carry out a risk assessment about the failure mood of gas storage well. Risk is the product of failure probability and failure consequences and risk analysis include qualitative analysis, quantitative analysis, and semi-quantitative analysis. Risk Management include risk identify, risk analysis, risk assessment and risk decision. Risk Based Inspection can not only reduce the risk, but also find the optimal solution between security and economy.Fault tree analysis is a deductive method with events linked by using logical gates. Weakness of gas storage well can be found by analyzing fault tree. Analytic hierarchy process is used to analysis weight coefficient of risk factors. Its result is more objective compared with other methods. As a method of semi-quantitative analysis, expert evaluating method absorbs the advantage between method of qualitative analysis and method of quantitative analysis. Expert evaluating method will avoid the shortage only through qualitative analysis and it makes the result more reasonable and accurate.In view of the above, the following work will be carried out in this paper:(l)The failure mode of gas storage well will be analyzed and hazard sources will be identified. The failure factors, including corrosion factor, cementing factor, design factor, leakage factor and so on, will be analyzed.(2)The minimal cut sets, structure importance and weakness of gas storage well will be work out by building gas storage wells fault tree.(3)Each risk factor weight of gas storage well will be determined by using AHP and It will be prepared for defining risk assessment method.(4)Risk assessment will be carried out by using expert evaluating method. Marking principle about failure possibility of gas storage well, marking mood about failure consequences and the level of risk will be determined to provide the support for risk assessment of gas storage well.(5) Case analysis is used on gas storage well, Reasonable measures are provided to reduce the risks.