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GSS student edition

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Yesterday I tried to enter data of weight percentage of some gases present in an oil field, so that the software could then calculate the fugacity, activity and partial pressures of these gases. When I gave the option to calculate to select what was the calculation I wanted, it indicated an error indicating that there is not an initial system specified.
What should I do? can you help me? would I skip a step?
Also, I would like to enter the reservoir temperature and pressure so that I can consider them in the calculation and I do not know how to do it.
Attached a screen print.



print error gwb gss.pptx

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Hi Raquel,

GSS is a spreadsheet for storing water analyses. As you've discovered, you can create "user-defined variables" to store certain properties, like your gas weight percents. GSS doesn't use these in any of its calculations, though. The only input GSS accepts for its calculations are the concentrations of the basis species (thermodynamic components in the fluid) and a few parameters like temperature, pH, and Eh. 

GSS can calculate gas fugacity or partial pressure from the activity of the dissolved gas species. You need to create a chemical model of the fluid to do this. For your information, GSS uses a program called SpecE8 to perform its calculations. You should familiarize yourself with SpecE8 before working with GSS.

From the screenshot of your spreadsheet, it appears you've already found how to add the temperature. Click +analyte > Chemical parameters > Temperature. For pressure, click +analyte > Physical parameters > Pressure.

For more information, please see the Using SpecE8 and Using GSS chapters of the GWB Essentials Guide.


Brian Farrell
Aqueous Solutions

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