Mass balance issue on mineral phase during CO2 injection in radial system

Hi everyone,

we use a typical case of CO2 injection (see details in Andre et al. 10.1016/j.enconman.2007.01.006) at 200 b in a radial system, so it was using the 2007 version of toughreact. The mineral disolution was linked to a complex mixture with dissolution kinetics, however to make tests we used simple calcite+dolomite equilibrium. When we just set up a batch case the CO2 drives calcite dissolution and the amount of Ca in solution is consistent with the carbonates dissolution (considering the water saturation). The amount of Ca has been compared to Phreeqc and it gives the same results.

When we set the same problem with a radial injection of CO2 gas the amount of Ca in solution is similar to the bach case. However the mineral dissolution is approx. 200 hundred times higher! So, for the whole system we get 200 times more Ca dissolved from minerals than Ca in solution (considering saturation and porosity). Mineral fraction change, the results in mol/m3 and porosity increase are all consistent. The issue does not seem to be related to the radial geometry as the dissolution amount in mol/m3 does not change with cell size.

This example was used for an intercomparison with a new coupling of OpenFoam and phreeqc in which we don't have this problem and the mineral dissolution is thus 200 times lower, for very similar CO2 amounts along the radial system.

Thanks for any help (we can provide all data if needed)

sincerely

Olivier Atteia