43 CFR 3108.10: Relinquishment.

The lessee(s) may relinquish the lease or any legal subdivision of the lease at any time. The lessee(s) must file a written relinquishment with the BLM State Office with jurisdiction over the lease. All lessees holding record title interests in the lease must sign the relinquishment. A relinquishment takes effect on the date the lessee filed it with the BLM. However, the lessee(s) and the party that issued the bond will continue to be obligated to:

(a) Make payments of all accrued rentals and royalties, including payments of compensatory royalty due for all drainage that occurred before the relinquishment;

(b) Place all wells to be relinquished in condition for suspension or abandonment as the BLM requires; and

(c) Complete reclamation of the leased sites after stopping or abandoning oil and gas operations on the lease, under a plan approved by the BLM or the appropriate surface management agency.