The role of mineral heterogeneity on the hydrogeochemical response of two fractured reservoir rocks in contact with dissolved CO2

2D reactive transport simulations that reproduce the variation in aqueous chemistry and the fracture geometry (dissolution pattern) were performed using CrunchFlow. Given that calcite dissolution reaction at pH < 5 is transport controlled, the calcite reactive surface area used in the model had to be diminished with respect to the geometric surface area initially considered in order to fit the model to the experimental data. The fitted reactive surface area was higher under faster flow conditions, reflecting a decrease in transport control and a more distributed reaction in sandstone compared to limestone.