Chemical reactions of carbonate-rich mudstones with aqueous CO2 and their impacts on rock's local microstructural and chemo-mechanical properties

Assessment of the structural integrity carbonate-rich rocks subjected to acidic brine strongly relies on understanding coupling between chemical changes and alteration mechanical properties rocks. This study aims at an integrated microscale chemo-mechanical microstructural characterization carbonate mudstones exposed CO2-rich under high pressure temperature conditions. Digital image analysis was performed X-ray micro-computed tomography (micro-CT) images realize evolution spatial distribution pores different material phases. approach showed three distinct regions porosity content (resulting from dissolution precipitation calcium carbonates), which are critical for being investigated. Detailed micro-CT also revealed preferred carbonates in parallel flow/reaction direction. Microscale testing using coupled grid nanoindentation scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) complemented results: zones close reacted surface were found have lower hardness indentation modulus while increased values adjacent observed. Also, thickness be considerably higher direction bedding planes, needs special attention laminated like shales mudstones. The layered structure expected influence overall rock. These results enhance our origin macroscopic brine.