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Shale gas reservoir is a typical type of unconventional gas reservoirs,primarily because of the complex flow mechanism from nanoscale to macroscale.A new triple porosity model(M3 model)comprising kerogen system,matrix system and natural fracture system was presented to describe the multi-space scale,multi-time scale,and multi-physics characteristic of gas flows in shale reservoir.Apparent permeability model for real gas transport in nanopores,which incorporate flow regimes effect,was used to address multi-scale flow in shale matrix.Simultaneously,geomechanical effects on permeability evolution was derived to impact into apparent permeability model,which is important to determine shale permeability.This combination of two effects forms a novel multiscale permeability model which covers the main mechanism of permeability evolution.Experiments on coal permeability were conducted to validate this model under various stress conditions.Model results were all in good agreements with the experimental data for coal,as well as for shale samples.The model results used for history matching also showed consistency against gas production data from the Barnett Shale.Finally,we performed sensitivity analysis on the contributions of shale deposits and reservoir permeability in different scales that gives some insight as to their importance.Simulated results showed that the influence of deposits in different porous media on production response reflect at the different stages of gas production.It was also suggested that free gas in matrix contributes the main source of gas production,while natural fracture permeability determines the gas production behavior.