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Alison

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Everything posted by Alison

  1. The "white space as zeros" option will not work with most versions of TOUGH, including those packaged with the PetraSim interface. This is because TOUGH element names are made of 3 characters and two numbers. For the number part, "04" is written as " 4" in a TOUGH and TOUGHREACT output files, so they are normally excluded from the input file created by the interface. Unless you are using a different simulator (for example iTOUGH2), you should disable this option.
  2. It is my understanding that the diffusion coefficient for all aqueous species is assumed to the be the same in TOUGHREACT. You might contact the TOUGHREACT authors at LBL to see if they have any ideas or planned developments on how to deal with this limitation.
  3. It builds the model first and then truncates it, so I don't anticipate you having any problems with the collar elevations not matching the DEM.
  4. My guess is that tens of thousands of points would be overkill. I would start with a smaller dataset and build up from that. Maybe increase the number of points to 8000 to see how it works first?
  5. Also, there are fields for strike and dip in the Stratigraphy table. Use the Tab Manager tool to enable the fields. If you populate these fields, then you would want to use the Dip interpolation algorithm during model creation: Unfortunately, other interpolation algorithms don't take strike/dip into account, so you really just need to experiment to see if this approach works for you. Limiting the number of points or applying a cutoff distance seems to help create more realistic surfaces.
  6. You will definitely need to resample the DEM or LIDAR surface to match your project dimensions. This can be done through the Grid|Math|Resample program under the Utilities. In most cases, you can import the DEM as an ArcASCII file (or some other format), but you may not be able to display it. You just need the RwGrd file to be created so that the resample tool can be used to bring it down to a resolution more appropriate for geologic modeling.
  7. I think this is a good approach. Depending on whether you need to model other units as well, you may want to add additional contacts to the database, both above and below ground (perhaps using an average thickness value for each unit). When creating the Stratigraphy model, be sure to use a "Constraining Surface" such as a DEM or grid that is based on borehole elevations. Feel free to send us your project if you are having a problem creating a model that reflects these superficial contacts. Best Regards, Alison
  8. I wanted to add a couple of additional suggestions. 1. An easy way to populate an optional field is to use the File | Locations -> Datasheet tool to transfer data in the Location table of the Borehole Manager Database to the Datasheet. You would want to do this AFTER adding the optional field to the database. You can then populate the optional field, possibly by copying and pasting, and then you can transfer the data back to the Database through the File | Transfer | Locations-> Borehole Manager tool. 2. You might consider creating a playlist that gives you to
  9. Thank you for submitting this. I do believe that you are correct, and that we should be writing a value of 1 for the PERMX value for extra cells. I have reported this to our programming team and will let you know when a new build is available with a fix for this problem. In the meantime, I think your only work around is to modify the INP file before running the model.
  10. I think that this error is probably related to the initial conditions you've specified. I believe that the fugacity coefficient is calculated by TOUGHREACT based on Pressure and Temperature. So, our first suggestion would be that you experiment with other CO2 partial pressures. Perhaps you should try a very small value, rather than a value of 0 for the cells with low partial pressure?
  11. Yes, for a constant Temperature boundary, you could use a very large density for the boundary cell.
  12. I have been experimenting with your model and converted it to EOS3 so that I could add gas saturation to the model. I was able to see the pH in the cell change by doing the following: 1. Adding the gas phase to the model. For example, initialize the model with 0.2 SG, or even just the cell with the high gas zone. 2. Under TOUGHREACT | Solution parameters, make sure that NGAS1 is checked on.
  13. Atmospheric boundaries can be simulated by making the cells at the top of your model “fixed state” or by assigning them a very large volume factor. You would then want to assign appropriate initial conditions that would represent the atmosphere, and would also want to create a special material to assign to those cells. This can also be done using the “extra cell” tool in PetraSim. You would again assign a very large volume to the extra cell representing the atmosphere and create very short connections to the top layer of cells in the model. I would recommend that you take a
  14. If all of these variables do not need to vary, then the "Fixed State" option would work fine. If you need to vary the temperature or pressure of the boundary, then the very large volume option (either set to geometric cells or an extra cell) would be more appropriate. This way, you could add large amounts of water or heat to the cells to force fluctuations in temperature or pressure. There is a discussion of time-varying boundaries in the PetraSim manual.
  15. If you do a literature search for TOUGHREACT and Clay Swelling, a few articles do pop up on Google. Many of them seem to be by the TOUGHREACT authors at LBL, so you may want to contact them to see if they have any tips on how the simulated the swelling of the clay minerals.
  16. I think the answer to your question is yes, but you may need to provide an example to confirm. When viewing model results in 3D, there is an option to turn on isosurfaces. These basically connect points of equal pressure and temperature. PetraSim does not create 2D contour maps. If you need to create lines of equal pressure or temperature (say, from a slice of a model), you would probably want to export results to another program such as RockWorks, Surfer or TecPlot.
  17. We are not able to duplicate this problem with one of our files, so we would need to see your SIM file to determine what is going on. We also need to know which version of PetraSim you are running. Best Regards, Alison
  18. Unfortunately, aqueous complexes were not output in TOUGHREACT v1.2, which is the version of TOUGHREACT that is packaged with PetraSim. This feature was added in later versions of TOUGHREACT. You might consider purchasing TOUGHREACT v3.3, which is available through LBL. PetraSim creates input files for TOUGHREACT v3.3. We hope to add better support with result visualization in the future.
  19. It seems that there is not enough output to show the results. I would recommend the following: 1. For cells where you want to see a detailed time series plot, you should check on the Print options for the cells and rerun the model. This will output data for each time step to a FOFT file, that is then displayed here. You can do this by right clicking on the cell and choosing Edit Cells. 2. You could also increase the number of time steps being output for all cells. This is done through the Analysis|Output Controls menu. The default is to print every 100 time steps
  20. This is a fairly common message to see during a model run that is often resolved by the simulator with a time step decrease. If you see this error at the beginning of a model, and it is not resolved by a decrease in time step, then it typically indicates a problem with your initial conditions. If the error shows up in the middle of the model run and causes the simulation to halt, then it would indicate that the simulation has reached a state not supported, such as a very high or low pressure or temperature. If you are not sure what the problem is, you could turn on the print option
  21. The SIM file you provided does not run. It says that it is missing components related to the Co2 and H2S gases. I am not able to help you set up your geochemical model. However, I do see that the initial conditions for the extra cell in your model are set to single phase with an air mass fraction of 0. This would simulate single phase water conditions. If you change the air mass fraction to 1, it will simulate single phase gas conditions. You should try changing this to 1 if you are trying to inject gas using the Extra Cell.
  22. I think we would probably need to see your SIM file to comment on this. Could this have something to do with the initial phase state of the extra cell?
  23. Because you are seeing this error at the beginning of the model run, it looks like you have poorly defined initial conditions. I would suggest you look at the input file to get more information about the problem with data initialization. If a different phase is evolving, (for example, if the water phase is evolving in a single phase system), you should try increasing the air mass fraction. You could also switch to a 2 phase system with a very high gas saturation.
  24. A gas injection zone option is not available in TOUGHREACT v1.2, which is the version included with PetraSim (it is included in TOUGHREACT v3.3, which is available through LBL, but it is not supported in PetraSim). One way to get around this would be to attached an "extra cell" to the injection cell, which a very large volume and a short connection distance. You can assign a gas zone to that cell that represents the gas components you want to inject into the model, and assign a higher pressure to the cell. You can find more about Extra Cells in the PetraSim manual.
  25. I would recommend that you take a look at a steam table (assuming you are injecting water) to get an idea of enthalpy at various pressure and temperature combinations. I am not able to post links on this website, but if you do a Google Search for "spirax sarco steam table", you should be able to get to a series of online calculators. If you are trying to inject at a constant temperature, you should know that the enthalpy needed to maintain a specific injection temperature changes with pressure. So, it can be tricky to inject at a constant temperature in TOUGH2. One op
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