| The Underground Gas Storage Reservoir (UGSR) plays an important part in gas exploiting and utilization, as one of the most effective method to adjust the disequilibrium between supply and demand of city gas.In an UGSR, a large part (30%~70%) of total gas stored is used as cushion to provide a desired deliverability. Base gas costs are a major cost item for new storage fields. This is particularly true for aquifer storage fields. Therefore, the use of less expensive inert gas to substitute all or part of the base gas requirements in UGSR is of significant economic interest, and it is a promising technology that has been successfully field tested in foreign.In this dissertation, research and development of gas storage in domestic and foreign are summarized. According to the operation mechanism of UGSR, a model on gas-water flow through porous medium for the Underground Gas Storage Reservoirs in aquifer is developed; when replace part of the cushion by inert gas, considering the mixing between the inert and natural gas, gas diffusion model is established. Based on above two models, the numerical model of the Two-Dimension Finite Element Method is build up successfully, and the finite element equation with semi-discrete method is deduced.By using the mathematical model developed in this paper, the construction and commercial operation in the aquifer storage when substitute part of the cushion by inert gas is simulated successfully and the factors that influence the mixing between natural gas and inert gas are analyzed.In this article,Matlab program language is used to solve the model. A set of finite element analysis programs are provided. By showing the results of calculation directly with figures, the transportation of gas and water, and the mixing between the different gases can be monitored and controlled at any time.The simulation results derived has much theoretical and utilizable value in aquifer storage when substitute part of cushion with inert gas.
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