Simultaneous Modeling of Homogeneous and Heterogeneous Reactions to Estimate Porosity Refinement during Carbonate Acidizing

Acidizing is a well-known method to improve the porosity and permeability of porous media. Therefore, having a comprehensive mathematical model in order to prognosticate porosity and permeability changes is of great importance for the success of this method. Most of the modeling approaches of acidizing consider one main acidrockreaction and ignore the presence of homogeneous reactions in porous media. We develop a precise mathematical model, which is based on a local equilibrium assumption, andconsiders all homogeneous and heterogeneous reactions in carbonate rocks. This model is applied on several organic acid injections to evaluate their performance on porosity alteration alongside precision in the system. In addition, an alteration of the reactive surface area during the acid injection with different injection rates is investigated. Oursimulations indicate that acids with a lower dissociation constant dissociate more gradually and they proceed further into the porous medium