Size air compressor for autumn blowout

[Qwertyjjj]

My irrigation system runs off a pressure tank at 30-50 psi with polypropylene pipe.
The longest run is about 200ft and it supplies around 10GPM.
What size compressor should I get to blow it out? 10cfm or less should be fine but how many gallons is required at a minimum?

 

[Gary Swart]

If water is still coming out when the tank empties, just shut it down and let it refill