Unexpected gas phase evolving
In a simulation case where no gas is defined nowhere in the initial conditions (Aqu with X_m_A=0) I am getting some values of gas at during the simulation.
!!!!!! "Phase1_Aqu_Eql": Gas phase evolves at element "A0046 " ==> P = 3.61403E+02 Peq_Hydr = 4.23236E+06 X_mA = 9.67257-219 X_mA_max = -7.36036E-08 Psat = 6.15685E+02
The line above appears in multiple instances and in the end the simulation crashes.
From the mass balances below you can see that though these values are small should not be there.
Is tehre anything I can do to tackle this issue?
Beginning of simulation:
COMPONENT MASS IN PLACE (Kg) ====================================================================================== COMPONENTS | Water CH4 Hydrate Salt ====================================================================================== PHASES | ----------------| Gas phase | 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 Aqueous | 1.25413599E+14 0.00000000E+00 0.00000000E+00 3.87877109E+12 Hydrate | 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 Ice | 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 -------------------------------------------------------------------------------------- TOTAL | 1.25413599E+14 0.00000000E+00 0.00000000E+00 3.87877109E+12
End of simulation
COMPONENT MASS IN PLACE (Kg) ====================================================================================== COMPONENTS | Water CH4 Hydrate Salt ====================================================================================== PHASES | ----------------| Gas phase | 8.54111331E+03 2.45126217E-09 0.00000000E+00 0.00000000E+00 Aqueous | 1.25415644E+14 2.90397035E-07 0.00000000E+00 3.87883434E+12 Hydrate | 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 Ice | 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 -------------------------------------------------------------------------------------- TOTAL | 1.25415644E+14 2.92848297E-07 0.00000000E+00 3.87883434E+12 | ======================================================================================
1 reply
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During a simulation with no gas phase initially present, if pressure drops somewhere a gas phase may form. The process could be water boiling, or a dissolved species coming out of solution. The message you show indicating a gas phase forms gives a very low pressure 3.614E2 Pa. If your pressure goes below the range of the equation of state you are using, the code will fail. A common cause for pressure dropping rapidly is too large a production rate for the permeability near the well, or a closed system with production rate greater than injection rate. I recommend checking your pressure distribution at the end of the simulation and seeing if you can tell what is causing the pressure to be so low.