Simulating Carbonate Dissolution with Digital Rock Physics

The increase in CO2-injection activities for Capture Carbon and Sequestration (CCS) and Enhanced Oil Recovery (EOR) is pushing the industry and the academia to explore the implications of rock-fluid interactions in full-scale development projects of carbonate reservoirs. Some of the questions are: Do reactions occur at rates that make a substantial impact on petrophysical properties? Are they relevant for CCS and/or oil recovery? How do they impact monitoring strategies? Carbonate reservoirs are notoriously difficult to characterize. Their abrupt facies variations give rise to drastic changes in the petrophysical and mechanical properties of the reservoir. Such heterogeneity, when further associated with variations in rock mineralogy due to diagenetic processes, results in a challenging scenario to model from the pore- to the field-scale. Micro-CT imaging is one of the most promising technologies to characterize porous rocks. The understanding of reactive and non-reactive transport at the pore scale is being pushed forward by recent developments in both imaging capability - 3D images with resolution of a few microns - and in modelling techniques – flow simulations in giga-cell models. We present a streamline-based pore-scale simulation method to predict the evolution of petrophysical properties of carbonate cores subjected to CO2 injection at reservoir conditions.