MODELING METHOD FOR GAS PRODUCTION OF CBM RESERVOIR ROCKS

The present invention relates to a method for modeling gas production in a coalbed methane gas reservoir. The present invention is characterized by including (a) dividing the reservoir in a coalbed methane gas (CBM) development area through computer modeling and thereby forming a three-dimensional grids having a plurality of cell, (b) actually forming at least one drilling hole in the development area and thereby obtaining a sample for each depth in the reservoir, (c) modeling the amounts of ash, water, and gas for the plurality of cells in the three-dimensional grids, (d) modeling the pressure change over time in each of the cells in the grid under a premise in which a production well is formed in the grids, and (e) performing a Langmuir experiment for a core sample obtained from step (b), calculating a Langmuir volume correction constant and a pressure correction constant for a case in which ash and water are excluded and only coal is present in the core sample, determining a Langmuir function for a maximum amount of gas adsorption with pressure and amounts of ash and water as variables, and applying the Langmuir function to each of the cells in the grids to calculate an amount of gas detected due to pressure change in each cell over time.