Pore-Scale Acid–Rock Reaction Numerical Simulation Considering the Heterogeneous Distribution of Mineral Components

Abstract

Abstract. Acidization is a vital method for enhancing carbonate reservoir permeability, but the acid–rock reaction mechanism and its impact on production are not fully understood. This study establishes a pore-scale acid–rock reaction model using the micro-continuum method and solves it with finite element analysis. The model investigates dissolution patterns, mineral content, and distribution, quantifying the impact of heterogeneous mineral distribution on porosity and permeability. The results show that wormhole and branch dissolution significantly affect the reaction, with solid volume fractions decreasing by 51.11% and 60.04%, improving porosity and permeability. Increasing dolomite content shifts the pore structure from branching wormholes to surface dissolution. Analysis of mineral distribution patterns indicates that longer acid fluid retention time aids in wormhole formation, with diffusion playing a key role in the dissolution process. This study provides a theoretical basis for optimizing acidification parameters in carbonate reservoirs, contributing to a better understanding of acid–rock reactions and their role in production enhancement.