By default, all wells defined in a ResFracPro model exist from the beginning of the simulation. Wellbore drilling times change this behavior, allowing a child well to be introduced at a specified point during the run.
This is particularly useful for parent/child well scenarios where you want the child well to be genuinely absent during the parent’s production history — not just inactive. Until the specified drilling time, the well does not appear in the 3D visualization. Once drilled, it becomes visible and can be activated for fracturing or production.
The most powerful application is in restart simulations. After running a single-well parent simulation, you can restart and introduce one or more child wells with specified drilling times. As long as the drilling time falls after the restart start date and the existing wells remain unchanged, ResFrac handles the introduction of the new well mid-simulation. This gives significant flexibility for efficiently testing different child well spacing scenarios.