In this study, we identify the key length and time scales associated with CO2 mineralization in basalt reservoirs. This is achieved through the development and application of a simple yet complete model of the fate and transport of a supersaturated CO2-charged fluid moving unidirectionally through an initially uniform basalt rock. The model consists of three coupled equations describing, (i) the spatiotemporal evolution of porosity with the mineralization reaction, (ii) the resulting temporal and spatially varying fluid discharge, and (iii) the fate and transport of the mineralization reactant(s) in the aqueous phase. A dimensional analysis provides length and time scales that characterize the extent and duration of field-scale carbon mineralization. These scales are applied to a field site to estimate poorly constrained mineralization parameters, notably, the effective first-order reaction rate constant.