Calculating the capacity of underground natural gas storage by material balance method

The capacity, effectively working gas volume and peak shaving capability of the underground natural gas storage reconstructed from the abandoned high-medium permeability sandstone gas reservoir are the important indexes of evaluating the gas storage, in which the capacity is the basis of designing the other important indexes of the gas storage. Therefore how to calculate accurately the capacity of the gas storage is very important. It plays an very important adjustment role in the success of failure of constructing the gas storage and in the upstream natural gas development and downstream natural gas demands. In general, when the gas storage is constructing, its capacity is smaller that the one (subsurface effective reservoir space) calculated by use of gas reservoir development data. So, it is necessary to check the capacity of the gas storage after the gas storage's being reconstructed, especially in the first gas-injection cycle. The gas reservoir dynamic reserves were estimated by applying the modified material balance method and the capacity after the gas storage's being reconstructed was checked up. Through practical application, it was proved that the prediction result is satisfactory.