initialization of water composition
Hi，
Recently, I tried to use toughreact (EOS1) to simulate fluid-rock interaction including dissolution and precipitation. But it always reminded me “convergence problem in initialization of water composition”. I tried to use PHREEQC to balance the meteoric water (from published article) and minerals, then input the parameters to tough react. It still remined me same error. I find no way to continue my research, please the specialists can provide help for me.
Posted files are 1D baisc files from toughreact332.
Best regards.
7 replies
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Hi,
The chemical inputs may not be possible. You have 7 molal Na+, which is well outside the range of Debye-Huckel. There is 3.53 M so4-2, but the guess is only 6.36E-04. Having guesses very different than the actual species activity will make convergence very difficult. The guess for SiO2 (aq) is 4 orders of magnitude smaller than the total, which also will not work. The guesses should be close to the total except for some redox species, Al, and Fe usually which can be very low if there are other complexes. Also you have listed nearly every secondary complex in the database. I would remove all of those and let the code pick them first.
Balancing the charge will not really make a difference in TOUGHREACT since it works on mass balance. Ideally the water should be balanced from the measurement, but the code will just try to keep mass balance not charge balance (technically, these will be the same).
ca+2 1 2.56E-03 4.20E-03 * 0.0
mg+2 1 2.12E-03 3.40E-03 * 0.0
na+ 1 6.27E+00 7.05E+00 * 0.0
k+ 1 4.77E-07 5.43E-07 * 0.0
hco3- 1 3.12E-07 1.73E-03 * 0.0
so4-2 1 6.36E-04 3.53E+00 * 0.0
cl- 1 1.04E-04 3.35E-04 * 0.0
h+ 1 7.93E-09 7.93E-09 * 0.0
sio2(aq) 1 4.82E-09 2.67E-05 * 0.0
h2o 1 1.00E+00 1.00E+00 * 0.0
alo2- 1 3.64E-11 2.02E-07 * 0.0
fe+2 1 1.00E-15 1.00E-10 * 0.0regards,
Eric
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Hi，Eric. Thanks for your suggestions. I successful solve this priblem and run my model during 20Ma. But I notice the warning messages in "runlog.out" (Species: mg+2 Relative error = 8.848E-02 Tolerance= 1.000E-03 Program execution was not aborted. Check results!). Could you can give me some suggestions?
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你能给我一些建议吗？我的水化学和矿物质可以在一维网格中运行 1000 年，但是当放入三维网格中时，就会出现 mg2+ 问题。这困扰了我很长时间。我希望能得到答复。谢谢。
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Hello Eric.. My name is Abdul Raashid and I have started recently using the TOUGH REACT. I am facing similar problem related to initization of water composiion and from your conversation I undertand that in my system I have more values of Na+, but I cannot change the guess values what should I do in that case. I have enclose water composotion for your review.Please advice me how I can get rid of this convergence error. Thankyou for ur support..regards..Abdul Rashid..
# INITIAL AND BOUNDARY WATER TYPES
1 1 !niwtype, nbwtype = number of initial and boundary waters
# Index Speciation T(C) P(bar)
1 40.0 1.0
# icon guess ctot
h2o 1 1.0000d+00 6.1900E+03 * 0.
h+ 1 1.9952E-07 0.4860E-03 * 0.
ca+2 1 2.0745E+01 2.0745E+01 * 0.
mg+2 1 3.2736E+00 3.2736E+00 * 0.
na+ 1 2.9053E+02 2.9053E+02 * 0.
cl- 1 9.1172E+02 9.1172E+02 * 0.
hco3- 1 2.6738E-03 2.6738E-03 * 0.
so4-2 1 2.7897E-01 2.7897E-01 * 0.
k+ 1 7.2585E-01 7.2585E-01 * 0.
fe+2 1 9.0731E-03 9.0731E-03 * 0.
nh4+ 1 7.2193E-03 7.2193E-03 * 0.
i- 1 2.5223E-03 2.5223E-03 * 0.
ba+2 1 9.7584E-05 9.7584E-05 * 0.
sr+2 1 1.0949E-04 1.0949E-04 * 0.
o2(aq) 1 1.0949E-07 1.0949E-07 * 0.
br- 1 7.3619E-01 7.3619E-01 * 0.
alo2- 1 0.0002E-04 1.0590E-04 * 0.
sio2(aq) 1 0.0000E-02 1.2180E-02 * 0.
fe+3 1 2.7219E-02 2.7219E-02 * 0.
B(OH)3 1 1.7825E-02 1.7825E-02 * 0.
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