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Alison

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  1. 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.
  2. 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?
  3. 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.
  4. 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.
  5. 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
  6. 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 tools for turning on and off groups of boreholes based on SQL Statements. I would recommend that you include one SQL statement that disables all of the boreholes in the database, and you can then include additional items that enable various groups of boreholes based on optional field data. You can check on only the statements you want to use depending on the group of boreholes you want to enable. Here are some examples of SQL statements: a. This statement will disable all of the boreholes UPDATE [Location] SET Enabled = 0 b. This statement would enable only the boreholes with an "x" in an optional field called "HPT" UPDATE [Location] SET Enabled = 1 WHERE ("Location"."HPT" = 'x') c. This statement would enabled only the boreholes with aExample SQL Statements.RwPlaylistn "x" in an optional field called "MIP" UPDATE [Location] SET Enabled = 1 WHERE ("Location"."Mip" = 'x') Obviously, these SQL statements will vary depending on the way you've set up the optional fields. To turn on the MIP boreholes, you would check on just the first and last statement (not the HPT statement), and then run the Playlist. I've attached a playlist with these three items so that you can download it and experiment a bit.
  7. 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.
  8. 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?
  9. Yes, for a constant Temperature boundary, you could use a very large density for the boundary cell.
  10. Alison

    Why

    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.
  11. 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 look a that LBL TOUGH forum for some additional technical details about this. If you do a search in that forum for “Assigning atmospheric boundary conditions”, you should be able to access a PDF with additional instructions provided by Stefan Finsterle of Finsterle GeoConsulting. You can find information specifically discussing atmospheric boundaries starting around page 20. If you are not able to find this, please send me an email and I will direct to you to this document (alison @ rockware . com).
  12. 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.
  13. 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.
  14. 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.
  15. 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
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