Net revenue interest (NRI) is the amount that is paid from well revenue i.e. in the aforementioned context of delivering NRI you are effectively getting a cost free royalty of 12.5, 18.75, etc. for a cash bonus. The oil company, Mach, will pay 100% of the expenses for the interest and receive back the NRI you delivered to them. You’re correct in leaning toward the higher royalty if you prefer a larger payout later, but that depends on the cash amounts. Other factors include how many wells are drilling, how much do the wells cost, and projected production. In general, the more production the better the royalty option will be; while, if they are only drilling one cheap well to hold their interests you’d be better off participating. You don’t want to ‘bite the hand that feeds you’ because they decide how much is produced, but you’d do well if you could shop this around.