ELECTRICAL AND PETROPHYSICAL PROPERTIES OF SILICICLASTIC RESERVOIR ROCKS FROM PORESCALE MODELING

摘要

In quantitative log interpretation it is common to assume that electrical conductivity is governed by Archie's law. The law is empirical and assumes a clean consolidated sand. Moreover, it also assumes that electrical conductivity is only present in the brine. Archie's law is parameterized by the cementation exponent denoted with m, and the saturation exponent denoted with n. The log interpretation requires estimation of n and m. Traditionally, petrophysical and electrical properties are obtained from laboratory experiments. In this study, we applied a direct pore-scale modeling approach to predict electrical and petrophysical properties across a wide range of rocks from the Norwegian Continental Shelf (NCS). The consistency of predicted properties was then verified against available datasets for the investigated samples. 20 siliciclastic reservoir rock samples from four different fields and four different formations of the NCS have been reconstructed using a pore scale modeling approach. For each sample, a 3D model of the rock was constructed based on thin section analysis and geological process based modeling. The reconstructed reservoir rocks have clay contents of up to 20% and well to moderately sorted grain size distributions. The permeability of the samples spans from 5mD to 2.2D and porosity from 0.14 to 0.30.