地下盐穴储气库泄漏原因及防治措施研究

Analysis of leakage risks and prevention measures of underground salt cavern gas storage

良好的密闭性能是盐穴储气库安全运营的基本前提,但地质赋存条件复杂、建库实践不足、理论体系不完备等均会导致盐腔遭遇各类泄漏风险。根据国内外的工程实践及事故统计,再结合盐穴储库特有的工程地质条件和运行工况,总结出三大泄漏因素(地质因素、工程因素、人为失误)和4种泄漏类型。地下盐穴储气库潜在的泄漏类型有夹层密闭性不足引起的气体近水平漏失、盖层被突破失效致使气体上窜、井筒完整性不足致使气体逃逸、夹层与断层连通致使气体流向断层。最终,依据各自的泄漏特征提出了相应的预防处置措施,以防止气体泄漏事故的发生和大范围的蔓延。由于我国盐穴储库的发展暂时处于上升期,研究结果对深部盐穴储气库的安全建设具有一定的借鉴和指导意义。

Good sealing performance is the fundamental prerequisite for a safe operation of a salt cavern gas storage engineering.However,the complicated geological conditions,the lack of practice in building gas storage,and the incomplete theoretical knowledge will lead to various leakage risks for the gas storage in the salt cavern.According to engineering practices and statistics on accidents worldwide,and combined with the unique engineering geological conditions and operational states of the salt cavern gas storage,three major leakage factors(i.e.geological factors,engineering factors and human activity)and four leakage types were summarized in this paper.The potential leakage types in underground salt cavern gas storage include near-horizontal leakage of gas caused by insufficient interlayer sealing,upward movement of gas through the strata caused by the breakthrough and failure of caprock,natural gas leakage along the wellbore due to its insufficient integrity,the gas flow to the faults owing to the connectivity between the interlayers and faults.Based on their respective leakage characteristics,corresponding preventive measures were proposed to prevent the occurrence of gas leakage accidents and its large-scale spread.In view of the fact that the development of salt cavern gas storage in China is temporarily at a developing period,this research results have certain reference and guiding significance for safety construction of deep salt cavern gas storage.