Modeling and simulation of the pore-scale multiphase fluid transport in shale reservoirs: A molecular dynamics simulation approach.

摘要

Shale resources provide a tremendous opportunity for a long-term viable energy source, but the lower hydrocarbon recovery rates are hindering the economic development of shale reservoirs. One of the main reasons for the lower hydrocarbon recovery rates is the inadequate understanding of the fate of various injected fluids and the recovered hydrocarbons during various stages of exploration and production.;As Darcy's law is limited in describing the multiphase fluid transport in shale, a comprehensive simulation framework is necessary, enabling the replication of the nanometer and subnanometer pores found in organic and inorganic matrices, and the simulation of the multiphase fluid flow in these nanopores, thus improving the comprehension of the pore-scale fluid transport process in shale reservoirs.;A molecular dynamics simulation-based framework is developed in present research to address the above-defined challenges. The applications of various open-source molecular modeling tools are integrated to develop molecular pore structures found in the organic and inorganic matrices. An application of the general-purpose DREIDING force field is extended to simulate the kerogen. A gas-liquid (methane and water) transport is simulated in nanopores confined in the organic and inorganic matrices, and various dynamic transport properties of fluids (subjected to confinement) are determined to gain the qualitative and the quantitative understanding of the fluid flow.;The present research provides a powerful molecular dynamics simulation-based framework that will enable the development of more complex models of nanoporous shale structures and address numerous challenges encountered in hydrocarbon recovery from shale reservoirs.