DEVELOPMENT OF MODEL FOR METHANE FLOW IN COAL AS POROUS MEDIA

Abstract

The primary objective of this work is to develop a model capable of predicting the single-phase flow of methane through coal as a porous media. The model was developed by applying the principle of conservation of mass on a controlled volume of coal seam and incorporating the Darcy’s law for laminar flow of methane. The model was solved numerically using implicit formulation of Finite Difference method. The result was validated with literature data. Predictions were made on the sensitivity of the model by varying parameters such as permeability, cleat distance, temperature, permeability, porosity, viscosity and the partial pressure. The result obtained showed that an increase in permeability led to an increase in effective stress and decrease in flow rate. Permeability and porosity are flow characteristics that influence fluid flow through its pores. The result also indicated that permeability is highly dependent on the applied gas pressure and the rock stress. The model will aid the extraction of methane for economical recovery and use, as well as underground mine degassing for safety reasons and also can be integrated into existing reservoir simulator to predict the variability of reservoir properties and how operating parameters affect performance under real conditions.