A Physical Model of Cementation and Its Effects on Single-Phase Permeability

In this paper, we present a mathematical model to quantify the effects of cements on the single-phase permeability estimate of clastic rocks. The model represents pore-filling, pore-lining, and pore-bridging cements by treating the cement particles as rectangular crystals attached radially to detrital grains. These clusters influence permeability through an increase in effective specific surface area and tortuosity. Because the model is based on physical principles, it is largely devoid of empiricism and should be applicable to a wide range of rock types. Permeability estimates by our model match experimental data from two sets of sandstone samples of five hydrocarbon-bearing formations in the North Sea. The model also confirms the well-known result that the effect of pore-bridging cement is a factor of ten greater in reducing the single-phase permeability compared to pore-lining and pore-filling cements.