Homogenization approach for liquid flow within shale system considering slip effect

In the last years, the huge success of shale gas and oil exploitation in North America and enhanced oil recovery by injecting carbon dioxide have attracted more attentions in petroleum industry. The reasonable scheme for shale oil production is a key step for sustainable and high-efficiency products of shale resources, which is dependent on the basic law of liquid flow. In this paper, a multiscale model is established based on homogenization theory to investigate the law of liquid flow within shale system. Considering the results of molecular dynamics simulation, the Navier-Stokes equation coupled with slip boundary is used to describe the liquid flow within microscale domain and the slip-corrected Darcy-like transport model in which clear physical meaning can be shown for every parameter can be derived for macroscale domain. In order to validate derived model, three cases including water and oil flow within simple nanopores are implemented and the results show that homogenization models match well with the results of molecular dynamics simulation for water flow with different contact angle and oil flow within inorganic pore. However, high-order slip-corrected model will deviate from the molecular dynamics simulation for oil flow within simple organic pore when pore size is smaller than 5.24 nm. Then the fractal porous medias are reconstructed based on Monte Carlo simulation and the several critical parameters are discussed. Finally, the results of homogenization model are applied in reservoir scale model to investigate shale oil production performance for economic evaluation and production optimization.