A fluid-solid coupling method for the simulation of gas transport in porous coal and rock media

Abstract

Understanding coal and rock permeability, and the corresponding influence on stress, is important in the field of energy development. In applied engineering, there is a tendency to employ three-dimensional methods that are simpler, less time- and cost-expensive, less computationally expensive, and larger scale. Thus, a numerical simulation fluid-solid coupling method is proposed in this paper. The proposed numerical simulation method utilizes the stress-permeability test results for elastic and plastic coal samples. The permeability models of the elastic and plastic coal samples under loading and unloading were obtained by fitting the experimental results and embedded them into FLAC3D software by using FISH language. The results of the uniaxial and triaxial flow simulations are consistent with the experimental results, thereby confirming the accuracy and feasibility of the numerical method proposed in this paper. This allows the permeability of the numerical reservoir model to be continuously updated according to the current stress level in the production process.