Understanding What is Below the Ground


#1

Not sure if this is the correct place or not. This forum has been most valuable to me, a noobie to mineral rights and their consequences.
I THINK I have found that if you strike oil in a “pool” down under, then others have some restrictions sucking out of that same pool (I may be wrong about this). On the other hand if I drill in someone elses pool, then I owe them? Where can I find out about these predetermined pools of oil, and how the ownership is divided up? Any help would be appreciated.