层状盐岩储气库物理力学特性与极限运行压力

分析研究层状盐岩中盐岩与夹层的孔隙率与渗透率,指出在未遭受变形破坏条件下,盐岩及其夹层本质致密,不会对储气库安全造成影响.但是,对盐岩与夹层的单轴和三轴力学特性、长期蠕变性进行实验研究与理论分析认为,盐岩与夹层间存在的力学特性差异及变形不协调,会造成2种岩性交界处的剪切破坏,影响储库安全性.在此基础上,提出层状盐岩储气库极限运行压力确定原则,包括顶板稳定、蠕变控制、腔体致密及裸井致密等,并结合实例进行分析研究.所得结果对我国层状盐岩中天然气储库的建造与运行具有一定指导意义及应用价值.

PHYSICO-MECHANICAL PROPERTIES AND LIMIT OPERATION PRESSURE OF GAS DEPOSIT IN BEDDED SALT ROCK

Bedded salt deposit is originated from cyclical sedimentation of salt rock and mudstone,anhydrite,or other non-salt rock interlayers;and the physico-mechanical properties determine limit operation pressure of gas deposit to some degree.The authors investigated the penetrability of salt rock and the interlayers;and it was pointed out that the naturally compacted salt rock and interlayers would not affect the safety of the gas storage,provided that they were not damaged.Then,some experimental investigations and theoretical analyses of mechanical and rheological properties of salt rock and the interlayers were carried out.It was concluded that the difference of mechanical properties between salt rock and interlayers could be found with some deformation variances of different lithologies and even shear damage on their interfaces.On the basis of the above studies,a set of laws were proposed for determining the minimum and the maximum operation pressures in bedded salt rock gas storage,including roof stability law,creep control law,cavern wall and naked well tightness law.Finally,an in-situ example for determining the limit operation pressure was analyzed with the given laws.The results are able to guide the construction and operation of the oil and gas deposits in bedded salt rock in China.