Importing *.THM Files in VMG Gasmod


VMG has been working hard to cross-pollinate powerful features through all of its products.  

This guide details how to import a VMGSim *.thm file containing the component slate into VMG Gasmod thereby making available the advantage of VMGThermo within VMG Gasmod and eliminate unnecessary re-entry of components when performing compositional modeling. 

This guide assumes a VMGSim case exists with a defined composition.


1. For VMG Gasmod to import the .thm file, water needs to be specified as the last component if it is to be included as a component in the .thm file. If your composition includes water, it can be moved to the end of the component list. To do so, in your VMGSim case, click on Thermo Model in the toolbar at the top of the screen Gasmod_1.png and select the Components tab.


Note the number of components. Click Sort.


In the window that appears, RIGHT-click on WATER and drag it to the bottom of the list. 


You can then export the .thm file by going to the Property Package tab, and clicking Export…


Choose *.thm from the Save as Type box and the file will be saved in the directory with your VMGSim model.


2. VMG Gasmod doesn’t allow spaces in the .thm filename so delete or replace any spaces.

3. The path and filename for the .thm file must be less than 99 characters so it is recommended to copy the .thm file to the VMG Gasmod project directory at C:\Gasmod\<project_name>

Importing the .thm file into VMG Gasmod

1. In VMG Gasmod, go to Data- Empirical Data- PVT Properties, select the Fully Compositional tab and check the Use Fully Compositional box.


2. Select the number of components you noted from the VMGSim model minus water. Therefore, if your VMGSim model had 16 components including water, you will want to specify 15 components in VMG Gasmod. This is because VMG Gasmod reports only the hydrocarbon components. Water is handled outside the composition. Enter the desired Min and Max Pressures for the property table generation. 


3. Click on the VMG Thermo button and choose the desired extent of VMGThermo use, and the Phase Correlation. Then check the Import Data File box and click browse to find the .thm file.  It will then be imported with the list of components. Again, VMG Gasmod reports only the hydrocarbon components so water will not show up in the list. The import of water can be confirmed by the greying out of the “Add Water as the Last Additional Component” box.


4. Highlight the Component Names from the list, press Ctrl+C to copy them to the clipboard and click OK.


5. Paste the Component Names into the Component Name column of the main PVT Properties screen.


6. Click on the Fluids button and enter the desired number of fluids, the region number, temperature and the composition (see the Important Note below).  Click OK to exit the Fluids screen and OK on the PVT Properties window.  The .thm file has now been imported and compositional modeling can be performed.


Important Note

Since VMG Gasmod handles water separately from the composition in the form of a Water/Gas Ratio (WGR) or as a Water Rate (Qw), a composition containing water must be normalized to exclude the water mole fraction. Therefore, the composition input into VMG Gasmod will differ slightly from that in the VMGSim model. Such a normalized composition is easily available in VMGSim through the following:

1. In VMGSim, double click the relevant stream and select the Equilibrium Results tab.


2. Check the Extended box and scroll down to the WaterFree Fraction line and expand it    


3. The bulk composition will be the one to enter into VMG Gasmod.

Please contact your local VMG office for more information.

Gordon Slemko, P.Eng., VMG Calgary

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