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层状盐岩储气库在长期运行期间,盐岩层与泥岩夹层两种不同岩石材料会因较大的蠕变差异引起变形不协调,在交界面产生剪切应力导致界面滑移破损,使油气沿着界面破损通道泄漏。结合我国在层状盐岩地质构造中建设能源储库的实际情况,通过对湖北云应地区层状盐岩中的盐岩和泥岩夹层的三轴蠕变试验表明,盐岩蠕变率比泥岩蠕变率至少大一个数量级。建立蠕变本构模型,对储库长期运行期内层状盐岩界面剪切应力的分布和变化规律进行数值分析,并讨论了盐岩稳态蠕变率不同时,界面层间剪切应力的变化情况。研究结果表明,界面层间剪切应力集中分布在靠近腔体的小段范围内,其后层间剪切应力迅速降低,且随着蠕变时间的增加,层间剪切应力增加的越来越快;盐岩的蠕变特性越好,层间剪切应力越大,当界面剪切应力达到界面抗剪强度时,就会发生破坏。蠕变试验和数值模拟结果,对于层状盐岩渗漏稳定性和密闭性研究具有重要指导意义。
During long-term operation of the stratiform salt rock gas storage, two different rock materials, salt rock and mudstone intercalations, will cause uncoordinated deformation due to large creep differences. Shear stress at the interface will lead to interface slip damage, Leakage along the damaged interface of the interface. Based on the actual situation of energy storage in the geological structure of layered rock salt in our country, the triaxial creep tests of salt rock and mudstone interlayer in layered salt rock in Yunying area of Hubei Province show that the creep rate of rock salt is higher than that of mudstone The creep rate is at least an order of magnitude larger. The constitutive model of creep was established to analyze the distribution and variation regularities of the interfacial shear stress in the layered rock salt during the long-term operation of the reservoir. In addition, when the steady creep rate of the rock salt is different, the interfacial shear stress Changes in the situation. The results show that the interlaminar shear stress is concentrated in a short distance near the cavity, and then the interlaminar shear stress decreases rapidly. As the creep time increases, the interlaminar shear stress increases more and more Fast; the better the creep characteristics of rock salt, the greater the interlaminar shear stress, when the interfacial shear stress reaches the interfacial shear strength, destruction will occur. The results of creep tests and numerical simulations have important guiding significance for the study of seepage stability and tightness of layered rock salt.