An Investigation into CO2–Brine–Cement–Reservoir Rock Interactions for Wellbore Integrity in CO2 Geological Storage

Geological storage of CO2 in saline aquifers and depleted oil gas reservoirs can help mitigate emissions. However, leakage over a long period represents potential concern. Therefore, it is critical to establish good understanding the interactions between CO2–brine cement–caprock/reservoir rock ascertain for leakage. Accordingly, this work, we prepared unique set composite samples resemble cement–reservoir interface. A series experiments simulating deep wellbore environments were performed investigate changes chemical, physical, mechanical, petrophysical properties samples. Here, present characterisation core samples, including porosity, permeability, mechanical properties, determined before after long-term exposure CO2-rich brine. Some further analysed by X-ray microcomputed tomography (X-ray µ-CT), diffraction (XRD), scanning electron microscopy–energy-dispersive (SEM–EDX). Moreover, variation ions concentration brine at different timescales was studied performing inductively coupled plasma (ICP) analysis. Although no significant observed permeability treated increased an order magnitude, due mainly increase sandstone component rather than cement or cement/sandstone Mechanical Young’s modulus Poisson’s ratio, also reduced.