Pore structure analysis of sandstones using computer-processed photomicrographs

A method was developed to digitize and quantify the pore networks of rocks using the apparent pore space observed in photographs of thin-sections. Statistical data are generated by digitizing numerous photographs, thereby making it possible to address the problem of pore structure. Pore structure is analyzed by specifying such parameters as the pore size and shape, anisotropy of the pore arrangement within the rock matrix, and pore connectivity. Quantitative information on pore size (perimeter area, surface to volume ratio, mean intercept length, and the largest pore dimension) is readily obtained. The use of at least two magnifications of thin-sections provides an accurate description of the pore size distribution. Pore shape, as determined by a shape parameter derived from the sterological data, is shown to correspond to a predominance of tabular rather than tubular pores. Several methods are outlined to determine the existence of anisotropy in the pore system. These methods showed no demonstrable anisotropy in the samples studied.