Comprehensive study of the anisotropy of microstructural and filtration properties of a gas condensate field reservoir based on digital core analysis

Modern technologies based on numerical simulation and X-ray microtomography provide new opportunities for detailed study of a reservoir pore space and prediction of its filtration properties The paper describes the findings of digital analysis of pore space and filtration characteristics of poorly consolidated sandstones in a pay interval of a gas condensate field located in the northern shelf of the Russian Federation. The study was conducted based on data from X-ray computed microtomography, digital core analysis methods, and numerical simulation. To build digital twins of a core, 3D images of the reservoir rocks were processed and binarized. Calculations of the directional variability of key reservoir properties including open and closed porosity, geodesic tortuosity, and percolation path characteristics were performed, as well as numerical simulation of filtration flow in three orthogonal directions. Special attention was paid to determining the representative elementary volume based on step-by-step averaging of porosity across cubic domains. The results demonstrate a weak but stable anisotropy in the filtration properties of rocks, associated with the directional structure of the pore framework. It has been found that even with similar values of open porosity, the geometry of filtration paths and tortuosity have a significant effect on permeability. The data obtained are of practical importance for geological and hydrodynamic simulations, optimization of horizontal well direction, assessment of sand production risk, and prediction of filtration front stability in offshore field development. The work emphasizes the need for a comprehensive digital approach when assessing the filtration properties of reservoirs in conditions of complex lithology and limited core material.