煤层气非平衡吸附的数学模型和数值模拟

煤层为微孔-裂缝双重介质,煤层气通过吸附作用吸附在煤孔隙壁面上而储集.文中建立了描述裂缝中气水两相渗流及微孔中非平衡吸附气体解吸扩散过程的数学模型,扩散到裂缝中的气体被视为源项,微孔中气体解吸扩散方程与裂缝中气相渗流方程通过微孔单元表面气压等于周围裂缝网气压的条件而耦合;考虑了单井径向流模型、垂直压裂模型及拟三维多井模型,并给出了相应的有限差分数值模型.

MATHEMATICAL MODELS AND NUMERICAL SIMULATION OF NON－EQUILIBRIUM ADSORPTION OF COALBED METHANE

Coal seam is a dual porosity media with microporosity and fractures,sometimes,coalbedmethane is adsorbed and accumulated on the surface of coal porosity by adsorption.Mathematical models are developed to describe two－phases percolation flow in the fractures and non－equilibrium adsorption and diffusion of the methane in the microporosity.Moreover,single－well radial flow model,vertical stimulated fracturing model and quasi－3D multi－wells model are considered,and finite difference schemes for these models are formulated as well.