The Transport Behavior of Liquid Hydrocarbon in Shale Nanopores

Shale, as the "tight" rock with abundant nanopores, exhibits extremely low permeability on the order of micro-nanodarcy. The classic Darcy law, being widely and successfully used in developing the oil in conventional deposits, becomes insufficient for that in deposits of the shale. In this work, on the basis of molecular dynamic simulation data available in the literature, a model for oil transport through a single nanopore is established considering the boundary slip and the varying viscosity of the confined oil. The results show that, to accurately predict the oil transport properties in inorganic and organic nanopores, the viscosity correction for the confined oil transport in the nanopores is necessary. The oil transport capability in organic nanopores is greatly enhanced compared with that predicted by the no-slip Poiseuille equation, significantly enhancing the flow capability in the scale of nanoporous media, while the small slip length in the inorganic matter (IOM) has neglected effect. This implies that the greater concentration of drilling activity needs to be implemented in the region with higher TOC, where there is the "sweets spots" from the point of oil transport.