Low-permeability natural gas reservoirs can be studied by analyzing pressure transients from formation testers, which provide high resolution data. However, the interpretation of these data require long wait times, leading to increased costs and the probability of losing tools in the well. Special interpretation models that use early-to-intermediate time data do exist for liquid flows in anisotropic, homogeneous, layered media. This project will extend these models gas flows. In Phase I, an analytical closed form solution will be obtained assuming anisotropic but homogeneous media under conditions in which pressures do not change rapidly. In addition, a more general numerical model will be developed for anisotropic layered formations. The models will be validated and calibrated against each other.
Commercial Applications and Other Benefits as described by the awardee: The interpretation algorithms should provide good estimates for the properties of natural gas reserves in low permeability formations in the United States , reducing exploration and production risk
