Structural Characterization of Rocks Using the X-ray Microtomography Technique

Abstract

In this article are presented the results obtained for the determination of mineral composition and petrophysical properties of eight sedimentary rock samples through a proposed new method, which is supported by X-ray microtomography image analysis (microCT). The results are compared with their corresponding ones obtained by traditional techniques in order to assess the efficiency of the new method. Three samples of carbonate rocks and five of sandstone were used in this study. Two sandstone samples come from the Rio do Peixe basin (BRP, at northeastern Brazil) while the rest were extracted from USA basins. The best results were obtained in the quantification of the mineral composition of the rocks and, consequently, in the estimation of grain density. Due to its insufficient image resolution, the microtomography was sometimes unable to quantify very small pores, giving low porosity values. The correlation between bulk densities measured by the two methods shows an intermediate efficiency. Although the results presented here indicate that the microCT image analysis is appropriate for quantification of mineral phases, this technique has potential for determination of many other physical properties, such as mechanical, electrical and fluid flow rock properties.