chance

Thanks Brian for your recommendation. I will look into the chapter. Regards.

Dear Brian, Thanks for your advice. I will check the carbon isotope values for fluid and carbonate to see if they are appropriate. I pulled those data from different sources. In both model, i have segregated the minerals. Is that right way to do? Thanks very much.

Dear Brian, I have a question regarding the isotope modeling of GWB. I have a system that CO2 is being injected into the cell at a constant rate. I am tracking how C isotope of CO2 is changing as it dissolves in brine. There are calcite calcite and dolomite in the system. They have a baseline C isotopes. I would like to simulate isotope of the CO2 injected during kinetic reactions of calcite and dolomite. Is this possible with GWB? I am getting very high unrealistic values for this simulation. I did the same thing for equilibrium reactions. The results were good and as we might anticipate. Thanks. Regards.

Thank you a lot, Brian. I will look into the sorption part of the GWB. Thanks again. Regards.

Dear Brian, Thanks a lot for your kind help. Yes, Iam using that isotope model. Did not know how to include the coal in the model. I will use graphite as a mienral then. One more quick question again, does GWB do adsorption of CO2 on coal (or graphite)and production of CH4. Thank you. With regards, Chance

Thanks Brian for such a quick reply. Im looking at the isotope farctination between injected CO2 and DIC in a formation water. However, the formation has coal layers. I was trying to include coal into the model to see any its impact on the isotopes. But no idea how to do so. Thanks a lot.

I was wondering if GWB can handle coal?

Thank you Brian. You helped a lot. Now its working. I didnt know that at first, I would open the surface dataset in addition to the thermo dataset. Regards, Chance

Hi Brian, I have a question for you again. I am trying to model the Ca++ exchange reaction on illite surface with H+ ion that is produced from CO2 dissolution in the brine. I prepared the cation exchange dataset for this reaction according to the example file IonEx that came with the software as you suggested. First I am using thermo dataset for the CO2 dissolution in the brine under 50 atm. Then,after I got the pH decreased, I changed the dataset to IonEX to model the illite surface exhange reaction between Ca++ and H+. But I think I am doing something wrong.I dont know the selectivity constant for this echange reaction. So, I am also playing with this parameter. Can you look at my files? Thank you. IonExIllite.datillite_exp.rea

Hi Brain, Thank you for your reply. You helped a lot. Regards, Chans

Hi all, I was wondering if GWB has a capability of modelling cation exchange reactions. If so, which database is used? Thank you, Regards, Chans

Thank you Brian. You helped a lot!! We didnt see any siderite dissolution in our lab work although we were expecting some dissolution. And then we tried to model our experiment. The model observation was same too. But i was not sure if i was conceptualizing the problem correctly with the sliding fugacity option of the program. Now I see it is the appropriate one after i discussed it with you. Now the fugacity of a gas is very clear to me. Thank you again for your kind help. Regards, Chans.

Hi Brian, Thank you for looking at my file. The pH=8.5 is the pH of initial brine. As the CO2(g) dissolves in the initial brine, I see that, in the model, the pH value is dropping to around 5 and more CO2 (aq) are being produced. So defining the CO2 fugacity as sliding at 50 atm is right? In our work, no siderite dissolution was observed. The model results shows no siderite dissolution either. Do you think our numerical model does not really reflect the conceptual model correctly? Also one more question to make sure one thing?? I thought fugacity was something related to the CO2 gas not to the CO2 (aq) species? Do you mean that as CO2 gas dissolves in the water, the CO2 fugacity increases? Many thanks!!!! You have been so helpful!!! Regards, Chans

Thank you Brian, I did get the run. But this time I want the CO2 fugacity at 50 atm. But i dont know how to define it in the model. There are 2 options as far as i understood: 1. fixed fugacity (I guess it is fixed at only atmospheric CO2. 2. Sliding fugacity. I dont want varying fugacity. How can I define set the CO2 fugacity at 50 atm. I am attaching the react file. Thanks again. Regards, Chans siderite(kinetics)_exp1.rea