Pore System Characterization of Carbonate Outcrops from Oman Using X-Ray Tomography Images and Permeability Relationship

Abstract

Summary Carbonates can exhibit a complex mineralogy and complicated pore system, and petrophysical properties of carbonate reservoir rocks can vary significantly because of the reactive nature of minerals during the diagenesis. In this way, carbonate outcrop rocks can be employed as analogous to reservoir modelling and understanding of the pore system properties as porosity and permeability. This study employs carbonate outcrop samples of limestone, dolomitic limestone, and dolostone from Sultanate of Oman, inserted in two distinct geological contexts at Huqf and Dhofar. X-ray micro-tomography images were correlated with mineralogical and petrophysical measurements to characterize the pore system properties of interest as porosity and permeability at different lithology. Mineralogy was affected by the dolomitization that may have caused changes in texture and pore system. However, density analysis showed that the dolomite occurrence cannot be considered as an isolated parameter for permeability evaluation. The computed pore size diameter, pore throat diameter, and medium pore chord were applied for pore system characterization and have a direct relationship with permeability, expressing best permeability for simple texture structure samples. PoA and DOMsize results allowed a good analysis of the pore complexities and effects on permeability, suggesting a great potential for rock evaluation.