Limit pressure of ellipsoid gas storage in laminated salt rocks

Key words:  ellipsoid gas storage  limit pressure  finite element method  tension strength

Abstract:

The underground gas storage in salt rocks plays an irreplaceable role in peak shaving and safety ensuring for gas supply. Therefore, determining the reasonable limit pressure of gas storage is of great significance. With regard to the limit pressure for ellipsoid gas storages, the limit pressures of different ellipsoid sizes of gas storages are calculated by using the finite element software ABAQUS. The limit pressures are discussed by the Mohr-Coulomb shear failure criterion, maximum pressure criterion and minimum pressure criterion. Besides, effects of the varying cohesion and tension strength of interlayer of underground salt rock gas storages on the limit pressure are studied. The results show that the limit pressure of the gas storage increases with the decrease of the ratio of the axis length of ellipsoid cavity. While the limit pressure of the same gas storage does not change with the variation of cohesion and tension strength. When different gas storages attain the maximum pressure, damage occurs at the top of the salt rock cavity, and for the minimum pressure, the damage area of the interlayer is basically unchanged. The existence of interlayer has little influence on the limit pressure of ellipsoid gas storages.