Initialization problem for ECO2N Problem No. 4 (rtp7)

Hello everyone, I'm new to TOUGH2.In running the fourth example of ECO2N, I don't understand how to set the initial conditions.

1. The manual mentions only involving boundary grid cells with elevations greater than 6000m. Is this to be specified through ELEME and CONNE files? Should the initial run only consider boundary grid cells, with no consideration for others?

2. How can the pressure at the injection well be kept constant during runtime?

3. In subsequent 2-D models, how can the boundary conditions from the previous 1-D model be preserved?

If someone could provide detailed answers to my questions, I would greatly appreciate it!