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T2WELL/ECO2N problem with mass rate

Dear TOUGH2 community users,

I am new to T2Well and I am trying to simulate pure gas-CO2 injection with several radial wellbore cells and only one big reservoir cell, but I am really struggling with trying to increase the mass rate. In the file attached, the model is for half a year and the mass rate is 53.78 kg/s. If I decrease the mass rate to, for example, 10 kg/s (which is really small), the model runs, but around 300s, it stops. What am I doing wrong? Thank you!

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  • Hello,

    My suspicion is that due to pressurization, CO2 temperature goes up in the wellbore. If you have formation around the wellbore, the heat will dissipate However, you do not. So the temperature increases to the point ECO2N module can handle and then stops. You can, however, add the semi-analytical solution (by setting MOP(15)=5, and see TOUGH3 User's Guide for how to set it up), but I am not sure if it is implemented here. Or you add some rock around it to see if that helps.

    Yingqi

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  • Hi Yingqi, thank you for your answer. However, I am afraid I did not understand what you meant. Could you please tell me give me an example of the corrected input file, please? Thank you very much!

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    • Jose Kevin Pauyac Estrada Ask for an output file at time 295s, right before the code stops. Check the temperature and pressure in your model. What is the highest temperature? If the temperature goes too high (i.e., ~100C, which is the upper limit the code can handle), add some formation rocks around the wellbore for the heat to dissipate. Check sample problem 3. It is a similar problem.

      Yingqi

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    • Yingqi Zhang 

      Dear Mr. Zhang,

      I fixed the problem of the temperature. You were right about going higher 100C. I defined in the ROCK block data for the wellbore an infinite heat specific. But, now I got another problem. After doing the temperature correction, now the model runs until 1500s, then it struggles. Attached, you will find a picture of the P-T at this time step. The bottomhole is being over-pressurized (more than 500 bars when the reservoir pressure is 50 bars). I tried to add two more reservoir cells as boundary conditions following the sample problem 3, but I get the same error. How could I fix this problem? 

      Thank you for your time and help! My apologies for the silly questions I may be asking. 

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