Geostatistical analysis of rock microstructure using the spherical harmonics expansion method

Geological reservoir characterization is based on rocks petrophysical properties. Nowadays, an important technique for retrieving these properties is X-ray microtomography, which allows for obtaining three-dimensional (3D) rock microstructure models. The detailed microtomographic information requires new theoretically substantiated techniques for data processing and systematization. Because the microtomographic models represent stochastic 3D objects, we assume that geostatistics is applicable. We find that the spherical harmonics analysis of the variogram field could be a method for the following characteristics detection: the complicated structure of the correlation lengths spectrum and anisotropy on 1 different scales. The classification base of rock microstructures is being extended by variographic analysis.