A Semi-Analytic Method for History Matching Fractured Shale Gas Reservoirs

Abstract

Abstract This paper presents a semi-analytic method to estimate reservoir parameters by history matching the production data of hydraulically fractured shale gas wells. The method is based on the analytical solutions to dual-porosity reservoir models. Algebraic equations developed by Bello and Wattenbarger (2010) for transient flow regimes which can occur in linear dual porosity model were used in this analysis. As far as practical values of reservoir parameters are involved, only two of the transient flow regimes would be seen in the field – bilinear and late linear. If matrix permeability is known, effective fracture permeability is estimated by doing regression on bilinear flow. Once bilinear flow is matched, linear flow part is also matched by regressing on fracture half length. Semi-analytic solutions are checked with actual data by making correction for gas properties change and desorption of gas at low pressures. When a satisfactory match of field data is obtained, reservoir parameters such as effective fracture and matrix permeability and OGIP can be estimated. Moreover, a future production of gas can be forecasted with estimated reservoir parameters for given economic constraints. The method was applied on hydraulically fractured shale gas wells from Barnett play. It gives good results in history matching and estimation of reservoir parameters. Considering the recent interests in development of unconventional reservoirs, this method is future promising technique in better understanding those types of reservoirs.