シェールガス貯留層内に存在するナノポアにおけるガスの振る舞い

Abstract

In recent years, the exploration of unconventional shale gas has been active in North America and production amount is currently still increasing. Shale gas is a hydrocarbon generated by source rocks and it is remained in place without migration. Usually these source rocks are shale. Furthermore kerogen is present in the pores of the source rocks, and shale gas exists in the nm order kerogen nanopores. Since the nanopore diameter is small, it is necessary to consider different physical properties compares with the conventional gas. That is, knowing the adsorption and absorption properties of shale gas to kerogen and the flow properties of the gas in the nanopore inside kerogen are essential matters for the future exploration and development activities for shale gas. In order to understand details of these phenomena, we simulate the adsorption and absorption phenomena of methane molecules to the kerogen molecules by using molecular dynamics method. Also the flow of the methane molecule through the nanopores is investigated by molecular dynamics, and indicating the presence of a slip flow. In order to scale up molecular simulation results, lattice Boltzmann method is adopted. Through these, we tried to build a numerical modelling system that can reproduce the physical and flow properties of shale gas in the nanopores.