Is there a requirement that they Gas company declare the unit before a well goes on line?

If so, must it be declared for a certain period of time before the well goes online?

Must it be registered at the court house? 

Can they change the unit declarations after they go on line.

On a pad near me, they are drilling multiple wells, some of which are completed. The gathering  pipeline has also just been completed.  I was wondering  what will happen as the wells they are working on are completed.  Will they  redefine the unit, to include the new wells or create new units?  I do believe that several of the leases have the  unit size limited to 640 acres.

Thanks for any info.

KingRon