The production behavior of CBM is complex and difficult to predict and analyze because it is governed by the complex physics including desorption mechanism, multi-mechanistic gas flow, initial gas content, and permeability evolution.
Numerical reservoir simulation is a reliable technique to estimate reservoir performance and production. Therefore, in this research, we developed a 3-D, 2 phase, dual porosity, dual permeability reservoir simulator with permeability evolution. By using the developed model, we also conducted a series of parametric studies to quantify the effects of desorption mechanism, adsorption capacity, multi-mechanistic flow, cleat spacing, initial gas content, permeability evolution, production pressure, and hydraulic fracture treatment.
From the results, the cumulative gas recovery will increase with adsorption capacity and initial gas content increased, lower flowing bottomhole pressure, larger diffusion coefficient, and smaller fracture spacing. We found that permeability evolution and initial gas content seem to impact CBM production more than other factors.
