jnabiyar
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Posts posted by jnabiyar
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Brian,
Thank you for your input. I would assume it would also work if I input Calcite as a Reactant but without any kinetics applied to it? Just a "simple" react?
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I'm having some trouble with X1t not simulating through the specific time range that I want it to. I have my model set-up to model from 0 to 1000, with an inlet-2 at 10 years. I noticed that when I take out my Kinetic Calcite out of the "Reactants" pane, it simulates all the way through. But when I leave it in there, it simulates to 1 minute. I have 89% Calcite. The other 11% doesn't really matter. I'm just wondering why it isn't simulating to 1000 years?
I have also attached the model.
Thank you,
Jay
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I am running GWB9. I am running the simulation from 0 to 1000 years. I am not sure why it is not simulating to 1000 years. When I run X1t, it plots it on Xtplot. It autoscales itself. I just can't figure it out.
Jay
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Brian,
Thank you. I'm not sure if you noticed but when you do run the model, and have a simulation period from 0 to 1000 years, it doesn't necessarily simulate to 1000 years according to the results. That is another issue that I am having.
J
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Hi Brian,
I do apologize. I sent the wrong script. This is the script that is giving me the problems. I'll insert an initial value of 16900 mg/kg and after the run, it will plot an initial value of 71500 mg/kg.
Jahed
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Brian,
Here you go. I have attached both the React and X1t files.
Let me know what you think.
Thank you,
Jay
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How do I do that?
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I promise this is my last question!
So, my when I am creating a 1D simulation in X1t, I am easily able to input my initial TDS values and can see it graphically starting at my desired TDS value. But in React, when give it my initial TDS value, it does not show it graphically starting at that value. For example, I have an initial TDS value of 16.9 g/L. For some reason it will plot a TDS value starting at 75 g/L at year "0".
Any ideas?
Thank you,
Jay
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Hi Brian,
Yes this helps. A colleague of mine created a flow through simulation model and was wondering how he was getting his porosity values.
Thank you very much.
Jay
Hi Jay,
Permeability is not currently calculated or used in React. Porosity, if the command is enabled, is calculated from the system's fluid and mineral volumes. It's not really used in any way by React, but you can plot how this porosity changes during a reaction path due to mineral precipitation or dissolution, for example.
You can start with some simple configurations in React before you construct a more complicated reactive transport model accounting for flow through a porous medium. Depending on what exactly it is you're interested in, you might use a flow-through path or a flush model. In the flow-through case, you follow a packet of fluid which reacts with an aquifer as it migrates. Any minerals that form as reaction products are left behind and isolated from further reaction. A flush model, on the other hand, tracks the evolution of a system (rock grains and pore fluid) through which the fluid migrates. At each step in the model, an increment of unreacted fluid is added to the system, displacing the existing pore fluid.
The flow-through and flush configurations in React are basically simplifications of what can be done with reactive transport models. A reactive transport model, since it predicts the distribution in space and time of the chemical reactions that occur along a flowpath, will give a more detailed representation of your system, though it is of course more difficult to set up.
Chapter 2 in the Geochemical and Biogeochemical Reaction Modeling textbook discusses these various classes of models further.
Hope this helps,
Brian Farrell
Aqueous Solutions LLC
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Hi Brian,
This makes perfect sense. I was actually getting confused with taking the log of 'k' but this makes a lot more sense.
Thank you.
Jay
Hi jnabiyar,
From the GWB Reactive Transport Modeling Guide:
There is no general relationship by which the permeability of actual sediments or rocks varies with porosity and mineralogic composition. For a specific suite of sediments or rocks, however, it is commonly possible to establish a statistical correlation among these variables. The programs use a correlation of the form
log k = (A x porosity) + B + Sum over m of (Am x Xm)
where A, B, and Am are empirical constants and Xm are the volume fraction of an arbitrary set of minerals indexed by m.
By default, the values for A and B in the correlation are set to 15 and -5, respectively, and no minerals are carried. The default describes a trend that has been observed in sandstone. The default settings, of course, are of no general significance. In constructing a model, it is important to remember that all such correlations are empirical, not functional constraints.
To set a permeability of 0.01 darcys (log permeability = -2) at any porosity, you could set A to 0 and B to -2. Thus, log 0.01 = -2 = (0 x porosity) + -2
If you would like permeability to change with porosity, you can enter a value for the A term (be sure you are calculating the porosity as a volume fraction instead of a percentage). If porosity is 50% (0.5 volume fraction), you could get the same permeability by setting A to 2, and B to -3. Thus, log 0.01 = -2 = (2 x 0.5) + -3
Does this make sense? You should read section 2.13 (Permeability correlation) in the Reactive Transport Modeling Guide for more information on setting permeability.
Regards,
Brian Farrell
Aqueous Solutions LLC
P.S. I moved your topic from the archive of old posts to the front GWB forum page.
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I am working on a carbon sequestration project. I am wanting to to simulate a flow through reaction model which I guess could only be done using the React program. I also used the X1t program to to conduct a "Closed system or continuosly stirred tank reactor (CSTR) which does allow the fluid to back react with precipitated solids as the reaction progresses. In the X1t program, it allows me to set initial TDS, permeability, and porosity values. But, the React program doesn't. Or maybe there is a way but I haven't figured it out yet. The React program does calculate a porosity and permeability values based on fluid/rock parameter inputs which is not reflecting the initial values that I want.
Any suggestions?
Thanks,
Jay
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How can you put in a direct value for permeability. For some reason the program provides an equation that incorporates porosity and some standard values ( permeability= A * porosity + B ), where A=15 and B=-5. It makes no sense. But when I do put in my porosity value and manipulate values A and/or B to equal my permeability, run the model, and plot it, the initial permeability value that I want is completely different from the one that is plotted. Any ideas?
Steam and Rock interaction modeling
in The Geochemist's Workbench
Posted
I was wondering if GWB is capable of modeling steam and rock interactions? Specifically steam at 250 degrees C? If so, how would you do that?
Thank you,
Jahed