Natural State geothermal model calibration using itough2

Hi Melissa,

I looked at both your TOUGH2 and iTOUGH2 input files and found several mistakes and misconceptions. They are too numerous to list here, so please carefully compare your input files with the revised versions I attach here.

Here are same major issues:

(1) In the GENER block, you forgot the decimal point for the flow rate and enthalpy. The rates you actually specified are thus 4 orders of magnitude (!) smaller than what you intended (I glean your intention from the ranges you specified in the iTOUGH2 input file). In a sense, this is good news: this mistake drastically changes fluid in heat flow in your system. The bad news is, that it seems your model has a much harder time running given these (much) higher rates. I don't have the time to look into tis, specifically since I don't know your system at all. 

Did you check the results when you ran this model using regular TOUGH2, specifically the generation rates printed at the end of each output time?

(2) The initial error message was clearly spelled out in the iTOUGH2 output file, so please check ii.out, not ii.msg for crucial error messages. In short, you need a space between the two real values defining a range, i.e.,

>>>> RANGE: -16.0   -14.0

instead of

>>>> RANGE: -16.0-14.0

(3) It bothers me a bit that the parameters you specified in the TOUGH2 input file are outside the range you specified in the iTOUGH2 input file. Of course, iTOUGH2 gives you a clear warning message to that effect, but still...

(4) Note that if you want to estimate different values for horizontal and vertical permeabilities, you have to define those as separate parameters (not combined into a single block, as you did).

(5) Your calibration data are at time 0.0, but that is also your starting time, not your steady-state time. Set the starting time to a large negative value, so iTOUGH2 automatically jumps to time zero once steady state is reached. You also need command >>> STEADY-STATE.

(6) You did not have a > COMPUTATION block at all.

(7) Assuming that all these issues are fixed, you will not get a reasonable inversion. You have a single, steady-state temperature profile consisting of only 9 temperature points. And you try to estimate 11 (!) parameters. This is an underdetermined inverse problem - it does not have a unique solution (with or without iTOUGH2). 

Here is what I propose:

Make sure your forward problem is correctly set up and runs to steady state.

Then go through the iTOUGH2 sample problems to get proficient in inverse modeling and the iTOUGH2 syntax.

Good luck,

Stefan

It also seems that STEINAR has been used for editing at some point.

Rivan,

Running your files immediately gives me the following error message:

*****  ERROR  *****
 * Error in file /Users/.../it2_30551/well.dat. Provide map in following format:
 * Number of points in space (NXYZ),
 * Number of points in time (NTIM),
 * X and Y coordinates of profile,
 * NTIM times when observations were taken,
 * followed by NXYZ lines:
 * Z(1)    (VALUE(1   ,I),I=1,NTIM)
 * ......   .....
 * Z(NXYZ) (VALUE(NXYZ,I),I=1,NTIM)
 *****  ERROR  *****
 

This tells you that:

(1) The issue is not related to the forward input file created by PetraSim (it runs just fine; try it by just doing a forward run instead of attempting an inversion).

(2) The error message clearly tells you (a)  what the issue is, (b) which file needs to be corrected, and (c) what the proper format is.

(3) Your header in well.dat does not comply with the format described in the manual and in the error message. Correct it to:

57
1
217734.71 9034439.46
0.0  (I can only guess that 0.0 is the calibration time you want; correct if different)
532.4404718     70.54375856
506.8963731     76.69010572

...                         ...

 

(4) In case you run iTOUGH2 under Linux/Unix, don't forget to indicate that file well.dat is needed as an input file. You can do this in tow ways:

(4a) On the command by typing: 

itough2 -fi well.dat it2.file t2.file 1 &

(4b) In the iTOUGH2 input file, by adding the following line any place you like:

FILE: well.dat

I did not look at the results of your inversion, but it starts running just fine.

Best,

Stefan

 

PS: I encourage everybody submitting posts in this forum to briefly describe the issue they have (i.e., not just "the program didn't work"). In almost all cases, there is an error message. Quoting this error message goes a long way telling everybody what the issue is, whether they are interested in this post, and what the solution might be.

Hi Rivan,

I was able to run your previous input file without any further adjustments and error messages (I did a few iTOUGH2 iterations).

Anyway, the error message refers to an output conversion error in the TOUGH2 forward run. I cannot see how this is related to the change you made in the iTOUGH2 input file (switching from PROFILE to MAP). Did the error occur during the very first forward run, or later?

Please check the bottom of file t2.out. If nothing obvious can be found there (which is likely, as you ran into a hard crash), check Line 940 of file eos1.f, which would tell you what variables were being printed when the formatting error occurred. In case you need help with that, please send me file eos1.f (from the executable name I infer that you use a rather old version of iTOUGH2, which of course is fine, but I need your version of eos1.f to be able to help you; you might as well attach your modified input files).

Stefan

Rivan,

Please let us know what the error message is. Is it the same as before? After 5-10 minutes, are you still running the first forward run? Did you look at the TOUGH2 output file?

Stefan