A discrete matrix fracture framework for simulating single-phase flow and non-isothermal reactive transport

Simulating realistic reactive transport problems in a porous medium with many fractures that intersect in complex ways is computationally demanding because of the non-linear interaction between (i) chemical and physical processes and (ii) the governing processes and the geological structure.

The simulation of such problems is carried out in high-resolution computational meshes to capture the coupled processes and account for the impact of fracture networks. In each of the mesh points, one must solve several chemical reaction equations and equations for fluid flow, heat transfer and solute transport. With the chemical influence on the geological media (like mineralisation changing the flow dynamics) and the interplay between the governing processes, the equations must be continuously updated in the time loop (such as rediscretise the PDEs).  The computational demands increase with the number of chemical species and with the complexity of the fracture network. For reservoir-type simulations, where fracture networks are highly complex, and there are numerous reactions, the computational demands are severe.

In this paper, we present a coupling between PorePy and Reaktoro to make simulating realistic reactive transport more computationally feasible. The coupling employs PorePy to mesh the fractured medium and discretisation of the PDEs and Reaktoro to solve the chemical reaction equations. The simulation examples show that the proposed numerical scheme indeed handles large reaction systems in computational domains with increasing geometrical complexity.