Dynamic Pore-scale Imaging of Reactive Transport in Heterogeneous Carbonates at Reservoir Conditions

Two carbonate rocks were studied experimentally at reservoir conditions at two flow rates using dynamic X-ray tomography. Cores of both homogeneous (Ketton) and heterogeneous (Portland) carbonates, were injected with CO2-saturated at 10 MPa and 50oC. Images were taken at between 30-second and 40- minute time-resolutions during injection. Reaction-induced changes in porosity, permeability, and structure were obtained by segmenting the images and extracting a pore/throat network. Differences in dissolution type and magnitude were found for each rock and flow rate. At the highest flow rates, Ketton displayed uniform dissolution. Conversely, Portland formed wormholes at high and compact dissolution at low flow rates.