[Opm] Cell Convergence Debugging

OPM User opmuser0 at gmail.com
Tue May 19 06:42:32 UTC 2020


Okay, it is the Volve model that you are trying to get to run. I can get 
this this to run on 2020-04 with various modifications due to OPM Flow 
not supporting certain keywords. The model is currently running and is 
taking the 10 day time steps as per the SCHEDULE file, and it 
occasionally chopsĀ  back down to 3.3 days and then builds back up again 
to 10 day time steps, but it does seem to be running okay given the data 
input. What I did was:

 1. Fixed ROCK keyword error - too many entries.
 2. Fixed RSVD keyword error - too many entries.
 3. Removed PRIORITY keyword as it results in an Exception.
 4. Fixed missing WCONHIST keyword Jan 1,2015
 5. Changed grid output option to EGRID.
 6. Remove grid file and included fault files and replaced by grid and
    files exported from ResInsight.

OPM Flow does not support the PINCH 'NOGAP" option or the ADDZCORN 
keyword. So I loaded the original model into ResInsight and then 
exported the grid and property data, so I should have the same initial 
data as the commercial simulator.

There are many warnings in the commercial simulator's PRT file regarding 
connections between different PVT regions and wells connecting to 
different PVT regions, this is probably the cause of the numerical 
issues. Although the model does use THPRES keyword to force initial 
equilibrium; however, as soon as production starts the fluids will mix 
and will cause numerical issues as mass conservation is being 
invalidated. If you look at the FIPNUM report you can see how much the 
fluids are moving around between the different regions, although the 
material balance error is surprising good.

I'll send you my files to your email address, but please bear in mind 
this is a work in progress, but at least it should get you going.

Spoke too soon.

This model runs okay up to Feb 2014, then just cuts to very small times 
steps (E-14) and never recovers from that, even though there are no 
convergence messages on the terminal (but there is in the print file :-( 
). So the issue is around 26-Feb-2014, so see if you can see anything 
happening around that period that may cause problems. It looks like the 
water injector I-F-IB is given a zero rate on 29-Jan-2014, instead of 
being shut-in, so that might be the problem - that is never a good idea.

_OPM Flow Suggestion to Developers.


 1. It would be useful to print a WARNING message every time a well
    opens a connection that is in a different PVT region than the
    current opened connections.
 2. Print a warning message if the target rate is zero and the well is
    open, this is a valid field operation, but may be OPM Flow is trying
    to solve for this rate - that would be fun.

OPM User
opmuser0 at gmail.com

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