Application of microtomography and petrography techniques for the characterization of porosity of synthetic carbonatic rock minerals before and after acidification processes

Abstract

The objective of this work is to physically characterize and analyze synthetic carbonate rocks through microtomography and petrography techniques, focusing on a comparative analysis before and after degradation with a reactive fluid. For this study, physical characterization analysis with computerized microtomography and petrography on the samples before and after the acidification procedure was performed. The petrographic analysis verified an increase in both intergranular and intragranular porosities after dissolution. The microtomography analysis quantified the maximum increase in porosity, from 11.8 to 41.3% in the two-dimensional analysis and 31.6–52% in the three-dimensional analysis of the porous structures. Furthermore, the pores were quantified according to their area, and data was obtained on the orientation of the pores, providing insight into the preferred paths of fluid flow. It was also observed that the microtomography technique was an effective tool for characterizing fractures in the samples before and after dissolution. Such analyses are crucial for the extraction and injection of fluids at high depths due to the mechanical and physical risks arising from the dissolution of minerals as well as changes in pressure, temperature, and saturation, all of which affect the stress state of the reservoir rock.