Abstract Modelling and parameterization of the fluid–rock interaction with consumption or production of mineral or organic rock compartments is discussed here in relation to quantification and macroscopic formulation of transport and reaction processes. One major uncertainty is quantifying the relationship between the internal specific reactive surface and the concentration of the reactive minerals. Proper understanding and quantification of microscopic phenomena like fluid–surface reaction is one precondition for prognostic extrapolations to macroscopic spatial and temporal scales. Thus, appropriate formulations are needed that describe microscopic heterogeneous reaction phenomena on macroscopic scales. The authors propose therefore to formulate potential functionality of the reaction rate on mineral concentration as being appropriate to describe reaction-induced changes in reaction rates caused by variations in the inner reactive surface. Sample calculations, including the reaction of acid mining water with calcium carbonate and the oxidation of coal demonstrate this proposition. To find functional correlations between the inner reactive surface and the reaction rates, the authors suggest paying more attention to the experimental investigation and quantification of the inner reactive surface of solid minerals. However, keeping in mind that reaction kinetics such as combustion modelling at high temperatures may have little control over an overall process, we should estimate the relevance of parameter sensitivity to reduce effort.

Keywords aquifer; Arrhenius; coal fire; fluid–rock interaction; numerical simulation; petrophysics; rock properties; stochastic