Pore Geometry And Permeability Modeling From Pressure Dependence Of Transport Properties In Sandstone

Abstract

In this paper, a model of the pore geometry of sandstones is proposed. Three categories of pores are considered: large spherical pores at 4-grain vertices, tube-like throats at 3-grain edges and narrow sheet-like throats at 2-grain faces. Tube-like and sheet-like throats control the transport properties whereas nodal pores dominate the storing capacity. Tube-like throats tend to enhance permeability and improve accessibility to the storage pore space. Exploiting the fact that these different types of pores .respond very differently to pressure, it is possible to evaluate the volume fraction of each category of pores in the framework of a simple capillary model. This approach was applied to data from the literature. Satisfactory fit was obtained for most of the sandstones considered. The exceptions seemed to be associated with high clay content which was not accounted for by the model.