(319c) Study of Petrophysical and Mineralogical Changes in Reactive CO2 Systems

Our research is primarily focused on better understanding the geochemical reaction, transport properties, and porosity and mineralogy changes of Sandstone, Limestone, and Dolomite in a reactive CO₂ system. Four batch reactors were setup to more fully understand surface reactions and a core flooding system was setup to analyze actual process conditions. Exposing rock samples of different surface areas - core plugs, fractured pieces, and powders - resulted in higher changes in porosity in the batch reactors. The changes of porosity and surface area of these samples were determined using Micro-CT and BET machines. Data from ICP-MS and QEMSCAN were also used to quantify mineralogical changes in these samples. In the second part of the study, a core flooding system was used to assess mineralogical and associated petrophysical property changes that result from flowing supercritical CO­­₂ and 2% NaCl brine through the cores. The changes in the core samples were observed using Micro-CT, QEMSCAN, and XRD and the data was supplemented with mineralogical measurements and data on brine chemistry obtained by ICP-MS. The reaction patterns observed in the core samples depend on the Peclet and the Damkohler numbers. Widespread dissolution patterns were observed throughout the core samples and precipitation was evident. Precipitation of iron carbonate in certain experiments was one of the most significant findings in both the batch reactor samples and the core flooding samples. The combined batch reactor and core flooding data also provides quantitative information between the extent of reaction and changes of porosity and permeability taking place.