Questions (for someone who knows, not for the peanut gallery...

Questions (for someone who knows, not for the peanut gallery please): A1 needs to be P&A before spudding (per annoucement):

1. Why (is it because the wells may transect each other, causing loss of pressure if P&A not done correctly?
2. How long does this take?
3. Does it need the drill rig onsite to do this (I presume there is top casing that needs to be removed/replaced, and then it is capped?).

Can someone with O&G experience please explain the process and timelines, so that the rest of us don't have to post stupid guesses as to what is happening and when.

Thanks in advance.

Kit.