Adding oil phase in phreeqc

[dat]

Hi,

I am going to model a mineral system that is saturated with oil and water with some salt concentrations.  I can add the water mass separately in the solution phase, is there any way to add oil saturation to the solution?

For example,  I want to create a solution with a water mass of 100 kg and an oil mass of 200 kg. How to input this to Phreeqc?

Appreciate your help.

[dlparkhurst]

Sorry, PHREEQC will consider only the aqueous phase, with no explicit calculation for the oil phase. If you check the literature, there are reports on how researchers have dealt with an oil phase. I think that they have used SURFACE to mimic losses of solutes to the oil phase, but you will need to read their papers. I think you should be able to find some literature that discuss a petroleum phase if you look at reports that reference IPhreeqc or PhreeqcRM.

[dat]

Thank you for letting that know.
Is there any database for surface complexation parameters and for K values, for minerals and other phases?

Thank you.

[dlparkhurst]

I haven't been following the literature. Dzombak and Morel data for HFO (hydrous ferric oxide) are in phreeqc.dat. There are some data for silica and alumina. You can also look at the literature for reports using CD-MUSIC which may cover some other minerals, but in general, I think you will need to search the literature.

[dat]

Hi.

I have been following some literature. They have done with the module SURFACE.

But that may not suit my purpose. I have a theory. Could you please let me know whether that will work or not?

Assuming the oil phase as COOH and define a solution master species and solution species.
Then add phases and reactions with that species. I plan to use reaction k values same as the values of SURFACE reaction values in the literature.

Will this be Ok?

Could you please let me know?

[dlparkhurst]

If you define COOH literally, then the species will be part of the C, O, and H mole balance for the aqueous solution. Further, the amount of COOH will be related to the log K for whatever association reaction you define for this species. If you use a realistic log K, the concentration of the species will be unstable relative to CO2, HCO3-, CO3-2, and other aqueous species.

Perhaps more importantly, all of the oil-phase species will enter into the activity of water equation, resulting in a low value for a(H2O). There is no way to avoid this effect. Any ions in the oil phase would be included in the ionic strength of the aqueous phase, which would affect the activity coefficients of all the species--aqueous and oil.

I think using SURFACE is the best approach. I think it has been used because you can completely separate the oil phase from the aqueous phase--no activity of water effect and no fictitious aqueous species. You simply distribute the elements in the system between the aqueous phase and the surface (oil) phase with surface complexation Ks.