Input of gaseous species

[Franco Galarce]

Hello!

Monatomic species in liquid phase were enter with "solution spread", but I have to enter data of monatomic and polyatomic gaseous species, and I only have the concentrations. How can I do it?


Thanks

[dlparkhurst]

I'm not sure what you have in mind. If you are talking about CO2, there is not an easy way to separate it from the carbon mole-balance equation of inverse modeling. CO2(aq) is calculated to be in equilibrium with the carbonate system, generally from pH and Alkalinity. If you define O2(aq) [O(0)], N2(aq) [N(0)], or CH4(aq) [C(-4)] in solution spread, they will be included in the mole balance constraints.

N2(g), O2(g), CH4(g), CO2(g), and others can be included as reactant phases. 

[Franco Galarce]

Hello dlparkhurst,

For gaseous species, I have concentration data for CO2, H2S, N2, CO, He, Ar, and water. For CH4 and H2 data, concentrations are below detection limit. I also have the gas-steam ratio (weight %) for each well. I need to enter this data in the modeling to predict the alteration mineralogy of a geothermal system assuming thermodinamic equilibrium. I also have data for temperature, pH, and aqueous species, which were obtained from wells, and already introduced in the inverse modeling input.

Thanks.

[dlparkhurst]

CO2(aq) and H2S(aq) cannot be defined directly in SOLUTION. They are calculated from CO2(aq) is calculated automatically from Alkalinity and pH (usually), and H2S(aq) is calculated from total sulfide, S(-2) and pH.

N2(aq) can be entered as N(0).

With some additional definitions (SOLUTION_MASTER_SPECIES and SOLUTION_SPECIES) He(aq) and Ar(aq) can be entered in SOLUTION.  llnl.dat has the necessary definitions.

CO(aq) would require an additional redox state [C(+2)] and aqueous species, which is also  defined in llnl.dat.

That said, I'm not sure how much some of these analytes will help in inverse modeling. Inverse models of mineral alteration will depend mainly on major ions in solution plus additional mole balance on major elements in minerals--Si, Al, and perhaps Fe.