Prediction of surface subsidence above salt rock gas storage using Mogi model

The main cause of surface subsidence above salt rock gas storage is the creep contraction of salt cavern volume during operation period. Assuming that the surface subsidence caused by equivalent elastic deformation of cavern volume contraction is a first-order approximate quantity of actual subsidence induced by creep contraction, the salt cavern is transformed as the sphere cavern with the same depth and volume, bearing uniform contractive elastic equivalent surface force. Therefore, the subsidence prediction is similar to the problem of boundary deformation of the sphere cavern with shrinkage force in elastic half infinite space. The Mogi model is introduced to get the elastic analytical solution of the surface vertical and horizontal deformations, which is the most successful method to predict the deformation above volcanoes eruption. The subsidence above the salt rock gas storage could be obtained directly with the volume shrinkage, which is the main superiority of Mogi model; and the prediction result has a good approximate effect to the numerical result under the same condition. It indicates that the Mogi model has enough feasibility in salt cavern subsidence prediction. Finally, the direction and recommendation about the further research are given.