Hello guys . Does anybody know how to simulate the deformation of the soil caused by fluidflow in both TOUGH and FLAC3D? Thanks

Floriane Youzan I didn't try the FLACTOUGH (FLAC calling TOUGH) implementation myself. I am suggesting it since the current implementation of TOUGHFLAC (TOUGH calling FLAC) alters TOUGH source code a lot which requires a really good knowledge of the Fortran language. It's even more complicated with TOUGH3 since you should now also consider that arrays are distributed in parallel. However, the TOUGHFLAC implementation is more optimized as it does not require to read and write TOUGH input/output files at each time step.

Assuming that you have already setup your problem for TOUGH and FLAC3D independently, a quick algorithm would look like as below:

1. Solve the mechanical state in FLAC3D to a time step Dt,

2. Calculate stress-induced changes in porosity and/or permeability and update TOUGH input files (MESH and/or INCON) with these new values,

3. Solve fluid and heat flow in TOUGH to time step Dt,

4. Import pressure and temperature from SAVE file and update zone pore pressure and temperature in FLAC3D,

5. Loop back to step 1 until end of simulation.

FLAC3D has a Python interface which should make this a bit easier to implement compared to using FISH. For instance, you can call an external program in Python as follow:

import subprocess

subprocess.call(["tough3-eco2n", "INFILE"], shell=True)

To update a zone pore pressure and temperature, I don't remember if there is a zone array for these properties, but you can loop over each zone and update the parameters as follow:

import itasca as it

for zone in it.zone.list():
    # Interpolate my_pp and my_temp from SAVE file
    zone.set_pp(my_pp)
    zone.set_temp(my_temp)

Reading TOUGH input and output files can be done using toughio. You can install toughio in FLAC3D by running this command in a Windows console:

cmd /C ""C:/Program Files/Itasca/FLAC3D700/exe64/python36/Scripts/pip.exe"" install toughio --user

Floriane Youzan Not sure about what you are asking. Assuming that your mesh is generated (with all zone groups assigned if necessary), you simply have to assign constitutive models and properties to your zones, initialize the initial and boundary stress conditions (e.g. roller at the bottom) and then solve the mechanical state to equilibrium.

Floriane Youzan I've attached a sample FLAC3D script. It shows the main commands to set up your model in FLAC3D.

Floriane Youzan It's a 2D model (extruded to 3D):

xlim = [-350000.0, 350000.0]

zlim = [-3000.1, 0.0]

Floriane Youzan Sorry for the late reply.

I never encountered this issue. Could you send me your script?

Floriane Youzan I am not sure what Line 4 is... is it the command

model configure fluid

that does not work?

Floriane Youzan You have to call

model configure fluid

before using

zone fluid something

Same for thermal, you have to call

model configure thermal

before using

zone thermal something

See my original script.

Floriane Youzan Put it at the beginning of the script. In my original sample script, it starts with

model configure fluid
model configure thermal

Floriane Youzan Of course.

In my sample problem, I applied roller boundary conditions everywhere except at the surface. To do so, I prevent lateral grid points from moving horizontally:

zone gridpoint fix velocity-x range position-x -350000.0
zone gridpoint fix velocity-x range position-x 350000.0

And grid points at the bottom of the mesh from moving vertically:

zone gridpoint fix velocity-z range position-z -3000.1

Since the sample problem is invariant in y, I fixed the velocity along the Y axis:

zone gridpoint fix velocity-y

but you shouldn't do that if your mesh is 3D.

Note that the mesh is 2D (XZ plane) with x in the range [-350000.0, 350000.0] and z in the range [-3000.1, 0.0].

Floriane Youzan You can read your SAVE file in FLAC3D using toughio.

save = toughio.read_output("SAVE")

This returns a namedtuple with a data dictionary that contains the primary variables X1, X2 ... up to X4. The number of primary variables and their meanings depend on the EOS you are using. For instance, for EOS3, X1 corresponds to pressure (or gas pressure if two-phase) and X3 to temperature. You can then update FLAC3D zones' pressures and temperatures using the instruction:

for i, zone in enumerate(it.zone.list()):
    zone.set_pp(save.data["X1"][i])
    zone.set_temp(save.data["X3"][i])

Floriane Youzan You can install toughio for FLAC3D's Python using the command:

cmd /C ""C:/Program Files/Itasca/FLAC3D700/exe64/python36/Scripts/pip.exe"" install toughio --user

Floriane Youzan Call that command in WIndows console, not in FLAC3D (just like you did with pip).

Floriane Youzan What's the error?

Floriane Youzan Can you attach the SAVE file you are trying to read?

Floriane Youzan Sorry for the delay. I wanted to fix other bugs and add other features before releasing an update. The latest update of toughio should be able to read your SAVE file now. Please update toughio.

pip install -U toughio --user

To update toughio in FLAC3D's Python:

cmd /C ""C:/Program Files/Itasca/FLAC3D700/exe64/python36/Scripts/pip.exe"" install -U toughio --user

Floriane Youzan You forgot the dash before U: -U

Floriane Youzan I notice that you installed toughio for Windows' Python installation rather than FLAC3D's built-in Python. This means that you won't be able to import toughio within FLAC3D. To run a coupled TOUGH and FLAC3D simulation (without modifying TOUGH's source code), you HAVE to install toughio for FLAC3D's Python as there is no way to import the module itasca outside of FLAC3D.

If you get an error when running the command:

cmd /C ""C:/Program Files/Itasca/FLAC3D700/exe64/python36/Scripts/pip.exe"" install -U toughio --user

it probably means that FLAC3D is not installed in its default location. What's the exact error returned by Windows console when you run this command?

Floriane Youzan You have to type it in Windows console, just like you did to install toughio for Windows's Python installation, the only difference is the path to the program pip (Python's package manager).

Floriane Youzan You forgot the option --user at the end of the command.

cmd /C ""C:/Program Files/Itasca/FLAC3D700/exe64/python36/Scripts/pip.exe"" install -U toughio --user

Floriane Youzan Have you restarted FLAC3D?

Floriane Youzan Is it an error related to _lzma?

Floriane Youzan What is the exact error returned by FLAC3D when importing toughio?

Floriane Youzan Okay, so the error is related to _lzma, as I thought.

Itasca packages the module lzma in FLAC3D but forgot to include the associated DLL file.

Download and uncompress the attached ZIP file, and put the file liblzma.dll in the following directory:

C:\Program Files\Itasca\FLAC3D700\exe64\python36\DLLs

Restart FLAC3D and retry.

Floriane Youzan You shouldn't save the data to FLAC3D file, you should import pressure and temperature data arrays from TOUGH in FLAC3D's Python, and then use itasca Python's module built in FLAC3D to import these arrays directly into FLAC3D's zones.

Assuming that your grid is loaded, the following code will import pressure and temperature calculated by TOUGH to FLAC3D's zones:

import toughio
import itasca as it

# Load SAVE file
save = toughio.read_output("SAVE")

# Loop over FLAC3D's zones and set pressure and temperature
for i, zone in enumerate(it.zone.list()):
    zone.set_pp(save.data["X1"][i])
    zone.set_temp(save.data["X6"][i])

You must change the primary variable names depending on the EOS you are using. From your SAVE file, I guessed that you are using EOS7R so pressure corresponds to variable X1 and temperature to variable X6.

Floriane Youzan 

import itasca as it

it.command("zone fluid zone-based-pp on")

If you are using module thermal, also add:

it.command("zone thermal zone-based-temp on")

Floriane Youzan To put it briefly, you can use 3 different languages in FLAC3D: FLAC3D commands, FISH and Python. Obviously, Python only accepts Python instructions.

Since

model configure fluid

is a FLAC3D command, you cannot use it as-is in a Python script. However, FLAC3D's commands can be used within a Python script using the function "it.command":

import itasca as it

it.command("model configure fluid")

Floriane Youzan Can you share your script?

Floriane Youzan What do you get with?

it.zone.count()

and

save.data["X1"].size

If your TOUGH MESH file has been created with toughio from your FLAC3D grid, you should have the same number of zones in both.

Have you imported your FLAC3D grid before running the script?

Floriane Youzan Looks like you imported your grid in FLAC3D thrice (18648 = 3 x 6216).

Run the FLAC3D command "model new" in FLAC3D's console (or "it.command("model new")" in FLAC3D's iPython's console), then reimport your grid once, and run your script again.

Note that at this current stage, you have merely imported the steady state results from TOUGH into FLAC3D. You should now loop over FLAC3D time steps (see my early answer).

Floriane Youzan What do you mean? The sample code so far only imports pore pressure calculated by TOUGH in FLAC3D. As I said earlier, you should now loop over time steps and sequentially couples TOUGH and FLAC3D:

t = 0.0
dt = 3600.0  # Time step, let's say one hour time step
tmax = 24.0 * 3600.0  # Simulation time, let's say one day
while t < tmax:
    # Code to solve fluid flow with TOUGH (e.g., using subprocess to call TOUGH)
    subprocess.call(...)

    # Import pore pressure in FLAC3D
    save = toughio.read_output("SAVE")
    for i, zone in enumerate(it.zone.list()):
        zone.set_pp(save.data["X1"][i])

    # Solve mechanical state in FLAC3D
    it.command(f"model solve mechanical time {dt}")

    # Prepare next time step for TOUGH
    # Modify input file using toughio
    # Rename SAVE file to INCON and modify porosity and/or permeability for each zone
    # (see Rutqvist et al., 2002 for equations)
    ...

    # Increment simulation time
    t += dt

Floriane Youzan No response, no problem. It means that the code ran successfully.

Now, FLAC3D can use pore pressure from TOUGH to update the mechanical state.

Floriane Youzan Yes, every units in TOUGH are defined following the International System of Units.

Floriane Youzan I thought it was obvious that the code was only partially completed. The command to put in subprocess to call TOUGH depends on too many factors such as how your computer is set up, which version and EOS of TOUGH you are using, is it compiled using WSL, Cygwin or you just got the executable file from LBL...