Does the thickness in y-direction matters when using XYZ to generate X-Z mesh?
Hello everyone,
I am using the TOUGH2/ECO2N code to simulate the injection of CO2. I intend to use XYZ MESHMAKER to generate a 2D X-Z mesh. So I want to ask that whether the thickness in y-direction has influence on the simulation results (e.g., the distribution of CO2 plume)? It seems that a large thickness value would mean a large cell volume and thus it can accommodate more injected CO2.
Thanks in advance,
Shaoxing
2 replies
-
Shaoxing,
Fundamentally, the thickness in Y direction has no impact whatsoever on the simulation results in a 2D model, as long as the injection rate (assuming you inject at a given rate using block GENER) is adjusted accordingly (i.e., doubled if you double the thickness dY). If you inject at a constant pressure (i.e., by making the volume of the injection element very large, typically 1E50, and setting the initial conditions for this element to the pressure and fluid composition you want), the saturation distribution will always be the same as well (of course, the injection rate in kg/s will be proportional to dY).
Because of this invariance, dY is typically set to 1 m.
Hope this helps.
Stefan
PS: I recommend to find the answer to this question by simply running TOUGH2 to find out what happens when dY is changed. It literally requires only a few seconds to change one value in the MESHM block, and one value in the GENER block, run it and compare the output files. Of course it is a good idea to first formulate a hypothesis (e.g., pressure and saturation distributions are independent of dY if a constant specific injection rate [kg / (s m^3)] is specified), but then use TOUGH2 to confirm or reject it. This way, you learn how to set up and run TOUGH2 models, and - more importantly - how to interpret the results.
-
Thank you Stefan. I will try to test different dY according to your advice. Thanks again.