Ross McCartney Posted May 30, 2016 Share Posted May 30, 2016 I have been trying to run an X1t model and I am getting the following error message: Step 16405, Xi = 0.071387 (Co = 0.092) -- Warning: Mass fluxes at node 0 are not charge balanced, z = 2.40794e-05Residuals too large, 669-th interationN-R failed at node 0Attempting to write last good time step for plotting.-- Warning, Node 0 has a charge imbalance of -1.113e-05 faradays-- Can't converge, abandoning simulation.-- Warning, Node 0 has a charge imbalance of -1.113e-05 faradays Is anyone able to give me some ideas about what the problem might be? Many thanks Ross Quote Link to comment Share on other sites More sharing options...
Brian Farrell Posted May 30, 2016 Share Posted May 30, 2016 Hi Ross, I'd be happy to take a look if you attach your X1t script. Regards, Brian Farrell Aqueous Solutions LLC Quote Link to comment Share on other sites More sharing options...
Ross McCartney Posted May 31, 2016 Author Share Posted May 31, 2016 Thank you, Brian. I have had difficulties uploading the script file so have e-mailed it to you at support@gwb.com. Many thanks. Kind regards Ross Quote Link to comment Share on other sites More sharing options...
Brian Farrell Posted June 2, 2016 Share Posted June 2, 2016 Hi Ross, In troubleshooting a model like this, it’s typically a good idea to scan through plots of various system parameters just to make sure everything looks okay. When I look at the mass of solvent water or solution, I notice that the value in the first interior node decreases drastically with time. Porosity similarly decreases to the point where there is almost no pore space remaining. Looking at minerals vs. time in the first interior node, you’re precipitating more and more as your inlet fluid flushes through, which is causing the pore space to disappear. At that point it’s understandable that the program fails to converge. You might consider conceptualizing the problem a little differently. Perhaps you need to account for minerals that precipitate according to a kinetic rate law instead of remaining in equilibrium with the fluid. Hope this helps, Brian Quote Link to comment Share on other sites More sharing options...
Ross McCartney Posted June 6, 2016 Author Share Posted June 6, 2016 Thank you for your diagnosis and recommendations, Brian, very much appreciated. Using a kinetic rate does work, allowing solids deposition to be transferred further into the formation. Many thanks and kind regards, Ross Quote Link to comment Share on other sites More sharing options...
Brian Farrell Posted June 6, 2016 Share Posted June 6, 2016 Hi Ross, I'm glad to hear that the recommendations helped. Cheers, Brian Quote Link to comment Share on other sites More sharing options...
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