[Opm] Cell Convergence Debugging

Hallam, Antony R arh5 at hw.ac.uk
Mon May 18 11:39:54 UTC 2020

I had some issues with the saturation properties which I’ve capped using OPERATE and that appears to be helping. I can let that play out and get back to you. Can I attach files to mailing list or what way to you all prefer to share things?


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From: OPM User<mailto:opmuser0 at gmail.com>
Sent: 18 May 2020 09:30
To: opm at opm-project.org<mailto:opm at opm-project.org>
Subject: [Opm] Cell Convergence Debugging


Alf is correct, in nearly all cases poor convergence is nearly always
related to the data: aquifer not in equilibrium with the hydrocarbon
zone, negative fluid compressibilities, etc. If you can share your model
then I'll take a look. If not then if you send me the *.PRT, *.LOG and
*.DBG files I'll have a quick look to see if there is anything obvious
from these files.

Also are you getting?

|Time step 2, stepsize -nan days, at day 0.04/31, date = 01-Jan-2021
NaN residual found!�[0m Problem: Solver convergence failure - Numerical
problem encountered Timestep chopped to -nan days|

Nobody  responded to my GitHub issue question "How Many Hours in a -nan
Day? #2503 " - perhaps it was something of a "black-hole" to investigate

I don't' have a general solution to this, but I have resolve a few cases
of the above due to data inconsistencies.

Release 2020-04 is out, so perhaps you can try your model with the new

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