层状盐岩中储备库油气渗漏风险的故障树分析

Oil and gas leakage risk analysis of underground storage caverns in bedded salt rock using fault tree analysis

油气渗漏是盐岩地下储备库事故的重要类型之一,具有突发性强、损失难以估计的特点。针对国内层状盐岩中储备库运营过程中的油气渗漏风险进行分析,揭示了油气渗漏事故的发生机制并建立了相应的故障树模型。通过对该模型的分析,找出了事故发生的各基本致因事件和故障模式,并得出适用于典型层状盐岩储备库油气渗漏事故的发生概率公式。分析结果表明,国内层状盐岩中储备库发生油气渗漏事故的可能故障模式有28种,且发生条件易于满足而难于防范,因此事故发生的可能性较大;按照各基本事件结构重要度的计算结果,盐岩强度低、盐岩蠕变过量、附近有断层、地震、造腔参数控制不当、非均匀地应力、人为操作失误等是层状盐岩中储备库油气渗漏事故的主要致因事件,并据此提出有效措施防止事故发生;通过专家调查法和故障树法的综合分析得出,金坛盐矿5口老腔储库在近10年的运营期内发生油气渗漏事故的概率为0.703%,属于偶发性事故。

Oil and gas leakage is one of the most important types of underground storage cavern accidents in salt rock,which has the features like abruptness and inestimable loss.By taking the underground storage caverns in bedded salt of China as research object,its oil and gas leakage risk in the operation process is analyzed;the mechanism of oil and gas leakage accident is revealed and the corresponding fault tree model is established.By analysis,mostly influence factors and fault patterns are found out;and the occurrence probability formula is deduced,which is applicable to the typical underground storage caverns in bedded salt rock.The results show that there are 28 fault patterns of oil and gas leakage accidents of underground storage caverns in bedded salt and this kind of accidents are likely to happen and difficult to prevent;namely,its occurrence possibility is pretty large;according to the calculation results of the basic events’ importance degree,low strength of salt rock,excessive creep of salt rock,fault near the cavern,earthquake,incorrect control of cavern construction parameters,non-uniform ground stress field,human error and so on are the main factors leading to oil and gas leakage accidents.By using Delphi method and fault tree analysis synthetically,it is concluded that the risk probability of oil and gas leakage accidents at five old caverns of Jintan salt mine in recent 10 years is about 0.703%,belonging to incidental accidents.