Speaker: Ahmad Mostafa

Date: Thursday 10th of March 2022, 1:15 pm.


In the last decades, pore network models (PNMs) have been widely used to study multiphase flow (e.g., (Blunt et al, 2001)) and reactive transport processes (Raoof et Hassanizadeh, 2010) in porous media, Several PNMs have been applied for modelling coalbed methane recovery but most of them do not describe the full coupling of multiple physical mechanisms involved. For instance, Jing et al. (2020) neglect the hydromechanical couplings, while Sampath et al. (2020) do not take into account all modes of diffusion as well as multiphase flow occurring in the cleat network. The objective of the PhD work is to develop a 3D discrete element method (DEM) coupled to a pore scale finite volume method (PFVM) to better understand the different mechanisms at stake during coalbed methane recovery. The method is hydro-mechanically coupled in the sense that changes in pore pressure produce hydrostatic forces that deform the solid skeleton, while deformation of the pore space induces pore pressure changes that promote interporal flow. The model describes adsorption and diffusion of gas within the coal matrix as a result of both Knudsen diffusion (pore pore) and surface diffusion (solid-solid). In addition, sorption induced deformations are taken into account by considering an additional pressure term related to the concentration of gas within the medium (the so-called solvation pressure)