Based on both experimental and theoretical investigations, the permeability of coalbed methane reservoir is studied and analyzed with reservoir depletion. Theoretically, a new analytical permeability model is proposed using MATCHSTICK geometry and constant volume theory. The new model incorporates primarily the changes in grain and cleat volumes and is, therefore, different from the other models that lay heavy on the pore volume and cleat compressibility. The model considers the effective stress and coal ma...