Geochemical Equilibrium between 2 water compositions
I understand how to obtain the speciation of one water composition in one grid block for a given thermodynamic conditions. But I want to know if it's possible to obtain the geochemical speciation of the mixing between 2 water compositions, setting both of them as initial waters, using only one grid block.
I would aprecciate any answers or suggestions.
If you only want to use one grid block, the only way to do this is to have one initial water and one injection water. Then use the GENER block to inject the second water into the first water. You would have to set the rock compressibility to a large value so the pressure doesn't increase too much. The other way is to use 2 grid blocks (one connection), each one with a different initial water, and allow diffusion to equilibrate the waters over some time period till it reaches equilibrium.
as far as I know you cannot inject two water compositions, because you have to unequivocally assign the injection water composition to each cell in solute.inp. However, you could connect 2 artificial injection cells to 1 mixing cell with a similar approach as described by Eric above.