卧式椭球盐岩储气库理论解及设计参数分析

我国的层状盐岩储层具有岩层厚度薄、夹层含量多、杂质含量高的特点，盐层厚度较薄时立式盐岩储气库有时难以获得较为经济的溶腔体积，通过提高储气库水平方向尺寸而建造的卧式储气库则可以达到经济体积的要求。从力学稳定性角度探讨卧式储气库的可行性，提出了卧式椭球储气库的力学简化模型。在前期研究的基础上使用弹性理论方法，推导了卧式椭球上关键点处以椭球形状比s（水平半轴与竖直半轴之比）、材料泊松比 、腔体内压 和远场应力（ 、 、 ）为函数的应力解。对理论解和数值解进行了对比，结果表明二者误差平均在3%左右。使用推导得到的理论公式，结合DP屈服准则，计算了当椭球形状比一定时储气库的最小运营内压值，得到了椭球形状比与储气库最小运营内压的关系曲线，并对卧式储气库运营内压的稳压范围进行了简单讨论。

Theoretical solution and design parameters analysis of horizontal ellipsoidal gas storage in salt rock

The layered salt rock formation in China has the characteristics such as thin in depth, too many interlayers, and high impurity contents. The vertical gas storages sometimes couldn’t get enough volume to meet the demands of economy when the thickness of the salt layer is thin. By improving the horizontal dimension, the horizontal gas storages were built in the salt formation which didn’t have interlayers could satisfy the demands of economic volume. To discuss the mechanical feasibility of horizontal gas storage, we propose the simplified mechanical model of horizontal ellipsoidal gas storage. Using the elastic theory method, we acquire the computational formulas of stress distribution of the key points with the help of other researchers’ results, which are the function of ellipsoid shape ratio, the material Poisson’s ratio, the operating internal pressure and the far field stress. The theoretical solution and numerical solution are compared; and the average error is about 3%. Taking Druker-Prager yield criterion into account and by applying the theoretical formula, we calculate the minimum operating internal pressure when the horizontal ellipsoid shape ratio kept constant, acquire the relationship between ellipsoid shape and the minimum internal operating pressure and discuss the range of operating internal pressure of the horizontal ellipsoid gas storage.