Help needed- Wellbore simulation

Hello Everyone,

I am writing to seek help with a flow problem. I have discretized a domain containing 26 layers. I want to inject CO2 into the lower part of these layers (say last 11 layers), through a wellbore. During the simulation, all CO2 is injected into the topmost grid block in the wellbore (note that the first vertical column of grid blocks is considered to be the wellbore), and TOUGHREACT decides the direction of flow. I was successful in running the wellbore simulation. However, as part of a sensitivity analysis, I am currently trying to force the injection of CO2 through only through lower parts of the wellbore. This requires not allowing flow in the upper parts of the wellbore during injection.

One thing that comes to mind is to change the layer to be injected into in the GENER file, I have tried this but for some reason the CO2 still comes from the top. Here are few other things I have tried that were mostly unsuccessful:

1. Changing the ISOT value of the upper parts of the wellbore. I know that ISOT in the CONNE block signifies how the grid blocks are connected (1 = horizontal and 3 = vertical). I have run a simulation where I changed the ISOT values for connections (vertically and horizontally) in the upper parts of the wellbore to zero.

2. I have also tried deleting the connections in the upper part of the wellbore entirely, to no avail.

3. Lastly, I tried entering the volume of the upper parts of the grid blocks in the wellbore (ELEME block in the MESH file) as zero or a negative number, as a way of signifying to TOUGHREACT that those grid blocks are inactive, but the simulation does not even converge to start with.

4. I assigned small porosity and permeability values to the upper parts of the wellbore in INCON before injection.

5. I added a new rock type called PACKR, for a packer. Then made PACKR  low porosity and permeability, and assign the rock type PACKR  to the elements of the upper parts of the wellbore in the MESH. The input files attached are from this injection simulation

I figure this may be a flow problem and have nothing to do with the wellbore, but I am still unsure at this point. Any insight at all will be greatly appreciated. Looking forward to hearing back.