![]() ![]() ![]() ![]() When flow is slow compared to reaction rate, the face of the porous medium closest to the inlet will dissolve and result in compact dissolution. The balance between flow, diffusion, and reaction rates determines which dissolution pattern develops during reactive flow in a porous medium 9. As such, accurate prediction of mineral dissolution in porous media is crucial for a wide range of subsurface applications, including CO \(_2\) sequestration and geothermal power generation 5, 6 where failure to predict the changes in permeability can lead to poor fluid injection efficiency and potentially irreversible reservoir damage 7, 8. Moving between regimes can result in orders of magnitude increase in permeability change with porosity evolution. Accurate identification of these regimes is essential as it is the regime that ultimately determines the evolution of permeability. The traditional conceptual model of mineral dissolution in porous media consists of three ‘dissolution regimes’ that guide prediction of flow and transport during reactive dissolution 1, 2, 3, 4. This work suggests that the traditional conceptual model of dissolution regimes must be updated to incorporate the channeling regime for reliable forecasting of dissolution in applications like geothermal energy production and geologic carbon storage. This focusing of dissolution along only dominant flow paths induces an immediate, large change in permeability with a comparatively small change in porosity, resulting in a porosity–permeability relationship unlike any that has been previously seen. Channeling occurs in cases where the distribution in pore throat size results in orders of magnitude differences in flow rate for different flow pathways. We investigate the boundaries between dissolution regimes and characterize the existence of a fourth dissolution regime called channeling, where initially fast flow pathways are preferentially widened by dissolution. In this work, we investigate the evolution of pore structure using numerical simulations during acid injection on two models of increasing complexity. The traditional model of solid dissolution in porous media consists of three dissolution regimes (uniform, compact, wormhole)-or patterns-that are established depending on the relative dominance of reaction rate, flow, and diffusion. ![]()
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