Petrophysical Characterization of Pore Type in Tight Gas Carbonates of Southwestern China

Abstract

Exploration and production in tight gas carbonates reservoir requires a comprehensive petrophysical characterization of rock microstructure in low-porosity and low-permeability tight carbonates. The complex pore system in tight gas carbonate makes pore shape must be taken into account for estimating elastic properties in rock physics modeling, differential effective medium(DEM) theory can be used to study the relationship between changing pore geometries and elastic properties. In this article, detailed rock physics modeling steps was put proposed, and on this basis pore type inversion algorithm was developed according to the concluded velocity-porosity relationship. Finally, Geological knowledge, core data, and well log data are integrated to discuss the pore shape effect on elastic properties of carbonate rocks in tight gas carbonates reservoir of Southwestern China, and the given pore type inversion result fits well with features of pore geometry which was revealed by thin section of cores and FMI image of local area, indicating this method can be can be effective to characterize complexity of pore system in tight gas carbonates.