Pressure Drop When Allowing Dissolution/Precipitation of Minerals

Hello everyone,

After I run a pressure initialization on the reservoir (REACT(1) = 2), I see that the gridblocks have pressures within the vicinity of that specific in PARAM. After I run reactive transport (without injection or production of any fluid) (REACT(1) = 0), I sometimes notice 50-100 bars of pressure drop across the whole reservoir. 

Here are some info about my reservoir: 

Last column of the reservoir at 30km (100th cell) has a volume of E50

Initial Temperature, Pressure, salt mass fraction, and CO2 molality = 40 C, 20.5 MPa, 0.05, 5E-6

Minerals present: calcite (@ equilibrium), anhydrite (@ equilibrium), dolomite (kinetically constrained) 

The reason I do all these steps is to ensure that the pressure profile of the reservoir is within that of my specifications and that the brine and minerals come to equilibrium with one another prior to any injection. I make sure log(Q/K) for the minerals present reaches close to 0 before any injection.