Characterization of the porous system of reservoir rocks with X-ray computed microtomography

Abstract

The structural characterization of the porous media of reservoir rocks plays an important role in petroleum systems research. Several techniques have been used for this purpose, for instance, 2D and 3D image analysis. Images captured from thin sections and other 2D techniques restrict the porous system characterization to a surface. Currently, X-ray computed microtomography (microCT) has been used to provide three-dimensional images of the samples structures. This paper shows the principles of the microCT technique applied to get 3D images of reservoir rocks. In order to demonstrate the potentiality of this technique, trhee sandstones samples (without significant clay formation within their porous phase) and one carbonate with multi-scalar pore sizes sample were analyzed. The microtomography measurements were accomplished with the SkyScan 1172 equipment, which can reach 1μm of spatial image resolution. A qualitative approach is followed by a quantitative analysis, where the porosity profiles and pore size distribution of the samples are measured. The employment of X-ray microtomography to get images of complex heterogeneous is discussed.