Nanoporous Gas Transport in Shale Gas Reservoirs

Abstract

In more conventional gas reservoirs, gas flow is simple, uncomplicated, and described by simple flux pressure drop expressions. In shale reservoirs however, this relationship takes the form of a more complex and multiscale flow process involving special flow mechanisms. Shale gas reservoirs often contain a significant number of nanopores leading to an apparent permeability that depends on pore fluid type, pore structure and pressure differentials. The complex geometry of shale reservoirs has drastically stimulated basic research on the transport mechanisms involved in the extraction of gas from shale formations. This study is aimed at studying the gas flow in nano pores. In this paper, permeation experiments for methane flow through nanoporous membranes were conducted and the effect of the pore size and pressure on the behaviour of the gas was analysed. The results obeyed the criteria to divide the flow stage into Darcy and Non-Darcy flow. As the pressure increases, the reservoir permeability also increases, and the gas tends to move faster thereby increasing the rate at which it flows per unit area in the system regardless of the temperature difference which means pressure gradient establishes the direction and rate of flow of gas in a reservoir.