基于可靠度理论的地下盐穴储气库矿柱稳定性

Pillar stability in underground salt cavern gas storage based on reliability theory

基于摩尔库伦准则建立盐穴矿柱失效函数,采用蒙特卡洛抽样法分析储气库矿柱安全可靠性,打破了传统方法难以对储气库可靠性具体量化的局限性。应用该方法计算了国内某盐穴储气库矿柱的可靠性指标和失效概率,结果表明:矿柱的失效概率随着盐穴埋深增加和夹层数增多而增大,随着储气库内压增大和矿柱宽度增大而减小;盐穴储气库的矿柱宽度对矿柱可靠性影响最大,在保证资源使用率最高的情况下,应尽量保证盐穴矿柱宽度/盐穴直径(跨径比)大于2;建议造穴时尽量采用埋深浅、夹层数少的优质盐岩层;储气库宜采用较大运行压力的运行模式,运行期间尽量减少低压运行时间。(图7,表3,参14)

Unlike traditional methods that cannot qualify the reliability of gas storage, this paper presents a new method to analyze the reliability of pillar in salt cavern gas storage by Monte Carlo sampling after establishing the failure fi.mction based on the Molar-Coulomb criterion. The new method is used to calculate the reliability indicator and failure probability of pillar in a salt cavern gas storage in China. The results show that the failure probability increases with the increase of cavern depth and interlayer number, and decreases with the increase of internal pressure and pillar width. The width has the greatest influence on the pillar reliability. Therefore, the pillar width divided by the diameter of salt cavern （span ratio） should be greater than 2 if praotical provided that the maximum capacity is maintained. It is recommended that high quality and low-buried salt rocks with less interlayers are used to build salt cavern storage. Operation at higher pressure is preferred for the gas storage, and the time of operation at low-pressure should be minimized. （7 Figures, 3 Tables, 14 References）