InterPore2026

A New Open-Source Porous Media Compositional Solver in OpenFOAM: Salt Precipitation Modelling in CO2 Storage in Saline Aquifers

21 May 2026, 15:35

1h 30m

Poster Presentation (MS07) Mathematical and numerical methods for multi-scale multi-physics, nonlinear coupled processes Poster

Speaker

Ali Papi (Heriot Watt University)

Description

Salt precipitation during CO2 storage in saline aquifers can plug the injection well and disrupt the storage process. Reactive transport modelling involving geochemistry in porous media, especially relevant to salt precipitation in CO2 storage processes in brine aquifers, is very proprietary and restricted to some commercial simulators. On the other hand, powerful open-source CFD (Computational Fluid Dynamics) simulators such as OpenFOAM are lacking a geochemistry modeller at the large (i.e., Darcy) scale. Although there is a package at the pore scale that couples flow transport in OpenFOAM with geochemistry in PHREEQC [1], a salt precipitation solver is still missing at both scales.

Through this research project, we have been working on developing an open-source solver in OpenFOAM that can cover the gap mentioned above. For this aim, we previously published a new OpenFOAM solver based on C++ (compositionalIGFoam) in InterPore 2024 [2] and released an update to this solver (idealCompositionalFoam) in InterPore 2025 [3]. These codes are able to account for the CO2 / water mutual solubility (CO2 dissolution in water and water evaporation in CO2) in CO2 storage processes in aquifers. In these codes, the impesFoam solver of the PorousMultiphaseFoam (PMF) package [4] in OpenFOAM was modified to account for the compositional interactions between liquid and gas phases . In this study, we have incorporated geochemistry (to clarify, salt precipitation) to the previous package. So, a 3-phase (gas / liquid / solid) 4-component (CO2 / H2O / Na+ / Cl-) model, called darcyCompositionalFoam, is developed.

The base code of this new package is not impesFoam, but it is coupledMatrixFoam [5]. This change of base code is to benefit from the advantages that this solver offers, as it accounts for fluid compressibility and also a solution for species transport equations. So unlike our previous codes, there is no need to develop a species transport equation in this solver. Additionally, because coupledMatrixFoam adopts a fully coupled approach between pressure and saturation, it is not bound to IMPES time-step limitations and can take up higher time-steps. Therefore, the runtime is reduced and speed is increased.

In this work, we further developed coupledMatrixFoam solver and incorporated a compositional model in this fluid transport modeller by adopting a segregated approach; This means that after each transport stage, an equilibration is conducted between all the 3 phases in the same timestep to incorporate a geochemistry module to the previous involved phenomena. A stability analysis is performed, and all the possible solid/liquid, liquid/gas and gas/liquid/solid equilibriums are investigated.

The validation of darcyCompositionalFoam was conducted against CMG-GEM commercial compositional simulator. The salt precipitation profile along a brine-saturated core model during CO2 injection was simulated and a great match was obtained (see Attachment). The contribution of this study is twofold; firstly, an open-source salt precipitation code with the precision of a commercial simulator is developed; and secondly, it pushes fluid flow modelling in porous media in OpenFOAM one step forward. Therefore, this work contributes to the advancement of knowledge in this field.