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ECO2M running stopped, unit temperature and pressure status abnormal

Dear TOUGH community users,

       The model is established using Ansys apdl starting from 0 m, with the first unit below the surfacecenter serving as the wellhead unit. The aquifer reservoir is located at -800~-850m (Supercritical CO2), and the wellbore extends to the bottom of the aquifer at -850m. The wellbore unit located in the reservoir is uniformly dispersed as 10m. The initial pressure distribution of the wellbore-reservoir system adopts a hydrostatic pressure gradient distribution, with surface pressure set at a standard atmospheric pressure of 0.1MPa.The pressure distribution is calculated based on P=0.1*10^6+1000 * 9.8h (h is the burial depth of the formation); The geothermal gradient is set at 25 ℃/1000m, the surface temperature is set at 10 ℃, and the temperature distribution of the wellbore-reservoir system is calculated based on T=10+0.025h (h is the burial depth of the formation); The lateral boundary of the model is the first type of boundary condition - constant pressure boundary (The Dirichlet boundary);The initial reservoir water saturation is 1.0, the CO2 mass fraction is 0, and the NaCl mass fraction is 0.lnject CO2 into the aquifer at pressure and temperature of 12 MPa, 25 ℃(pressure value higher than the saturation pressure of CO2 at the selected temperature,corresponding to an enthalpy value of 0.252528E+06 J/kg), with an injection rate of 10kg/s and a simulation time of 10 days.

     During the simulation process, the program stopped running when it reached 0.640102E+06s (approximately 7d). The wellbore unit FG54 located in the reservoir experienced a pressure drop to 0.1000000 E+05Pa (the lower limit of the pressure value in the CO2TAB table) and a temperature rise to 290.0337 ℃. What is the reason for this situation and what adjustments should I make? I have attached the input  file above. Thanks very much!

 

3 replies

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    • kenny
    • 3 mths ago
    • Reported - view

    where did you get the enthalpy value of 0.252528E+06 J/kg? ECO2M use different enthalpy value which is shifted from the data from NIST web book with a constant of 302192.0d0. If you get the enthalpy for NIST, you need input enthalpy by 0.252528E06+302192.0d0

      • happy12688
      • 3 mths ago
      • Reported - view

       Hello, thank you for your answer. I ran a simulation to determine the specific enthalpy value,in which one element has the given P&T conditions and it is saturated by CO2 only.Then I read
      the CO2 enthalpy in the output file.I am unable to determine whether the phenomenon is due to specific enthalpy or other reasons. Do you have any insights? Thanks!!

      • kenny
      • 3 mths ago
      • Reported - view

       

      I do not know how does your  model get a enthalpy of 0.252528E+06 J/kg which is not in the range of the table provided in CO2TAB for pure CO2. If you inject pure CO2, its enthalpy should be in the range provided in CO2TAB. 

Content aside

  • 3 mths agoLast active
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