Characterizing pore structure and CO2 storage potential in Eocene Mirador Formation tight sandstones using X-ray micro-CT

Abstract

This study utilizes digital rock physics and X-ray micro-computed tomography (μCT) to comprehensively characterize the pore structure of the Eocene Mirador Formation tight sandstone from the NW Llanos Basin, Colombia. Petrographic analysis identifies the sandstone as predominantly quartz arenite with minimal clay content. Quantitative mineral mapping through scanning electron microscopy further elucidates key rock-forming minerals and their textural and microstructural characteristics. The analysis of petrophysical properties reveals low porosity (3.3 %) and high compressive strength due to significant secondary quartz cementation. Detailed 2D and 3D μCT imaging provides insights into pore structure, size distribution, and connectivity, highlighting a predominance of small pores that influence both porosity and permeability. The presence of fractures impacts fluid flow, while pore connectivity is crucial for reservoir quality assessment. The study underscores the importance of imaging resolution in accurately characterizing pore geometry and connectivity. A 3D digital core model, created with PerGeos software, offers a detailed representation of the pore structure. These insights enhance the understanding of the Eocene Mirador Formation's pore structure, contributing to CO₂ storage potential assessments and providing valuable information for hydrocarbon exploration, resource management, and geotechnical engineering.