43 CFR §3903.51

1. (a)Each lease must meet its minimum annual production amount of shale oil or make a payment in lieu of production for any particular lease year, beginning with the 10th lease year.
2. (b)The minimum payment in lieu of annual production is established in the lease and will not be less than $4 per acre or fraction thereof per year, payable in advance. Production royalty payments will be credited to payments in lieu of annual production for that year only.