Increase time step size?

Hello,

I am working on modeling the flow of CO2 and H2O in the hydrothermal system of a volcano using ECO2N V2. My eventual end goal is to have a cylindrical mesh (depth of 4.5 km and radius of 40 km) with CO2 and H2O being injected at the bottom.

I first started by making a small version of the mesh (depth of 4.5 km and radius of 100 m) in order to get my input file working correctly. I started by running the smaller model without any injection in order to allow the pressure/temperature/whatever else to equilibrate and reach steady state. I then ran the model again from those initial conditions while injecting CO2 and H2O and I got it to run to 50-100 years with no issues, which is about as long as I need the model to run.

However, now I am working on scaling my model up to the full size I need and I’m running into issues that I have been unable to resolve. I have increased the size of the mesh to a radius of 10 km (still with a depth of 4.5 km). Again, I’m first running the model with no injection in order to allow things to equilibrate and reach steady state. As far as I can tell, it is running without any errors, however by the time the model reaches 9999 time steps, it has run for less than 2 years and the time steps it is taking are tiny (less than 500 seconds). I know that I can increase the maximum number of time steps and let the model run for longer, but when it is only increasing by at most 500 s each time, the model might take days to run.

So, my primary question is whether there is something I am doing or not doing that is impacting the size of the time steps and whether there is a way that I can increase it so that the model might run faster. I have attached the files associated with this if that is helpful. I would really appreciate any help that people can provide!

Thanks!

Karissa