Earth & Environmental Sciences

Flow in natural media with nanoporous regions is very complicated, with many governing processes. Welldeveloped numerical codes to integrate and model flow through these media are available. A great deal of very creative work has been done to understand individual processes governing flow in natural media with nanoporous regions, and both simple and elaborate tools have been used to gain process understanding. The complications in understanding and predicting flow in these rocks, particularly with multiscale heterogeneities, anisotropies, and the presence of multiple phases and large gradients are enormous. Here, we examine factors governing flow through natural porous media containing nanoporous regions. We present a conceptual model of the media, touch on the flow physics, and describe the techniques used to examine pore space in these rocks. In addition, we briefly describe some modeling of flow through these media. A number of processes which need better description are identified.