Carbonate Pore Shape Evaluation Using Digital Image Analysis, Tomography, and Effective Medium Theory

Carbonate rocks have a wide variety of pore shapes and different types grains, which greatly affect the elastic properties characteristics reservoir. This causes certain difficulties in petroelastic modeling. One problems is scale input data, then used to build rock physics model. The paper presents results studying three core samples carbonate Upper Devonian Lower Carboniferous age, are located South Tatar arch (Volga-Ural oil gas basin (Russia)). To evaluate structural space, effective medium theory used. data laboratory studies that include measurements velocities longitudinal transverse waves, porosity, thin section computed tomography analysis. When using tomography, analyzed at resolution (12–37 µm/voxel). space scales provide rather values porosity aspect ratio. tomography-based estimations also differ from experimentally measured (up 10%). provided by datasets model for studied helps estimate wave with methods (self-consistent approximation, differential (DEM), Kuster–Toksöz method). A comparison velocity their experimental analogs dry may indicate presence microcracks whose size beyond resolution. Improved models incorporating both pores predict fluid-saturated range. It demonstrated predicted significantly 30%) those (RP) constructed without support results. Moreover, other considered difference theoretical attributed changes host matrix as compared calcite polycrystal, caused various reasons.