Montana Division Payout on vertical oil wells question

I'm familiar with the pay out system in the ND Bakken (by acres per section on horizontal etc.), but what are Montana rules on payout on vertical oil wells? Is it a radius? If so how far? Just checking for a friend who has a new adjacent well. It is a new well and has been spudded. I would imagine he won't know until Division Orders are developed. If someone could just poiint me in the right direction with a URL.