Del. Code tit. 7 § 6125
The lessee may at any time file with the Secretary a written surrender of all rights under the lease or any portion thereof or any separate or distinct zone or geological horizon or any portion thereof. Such surrender shall be effective as of the date of its filing subject to the continuing obligation of the lessee to pay all rentals and royalties theretofore accrued and to place all wells on the lands or in the zone or horizons surrendered in condition for suspension or abandonment in accordance with the applicable lease terms, regulations and law. Thereupon the lessee shall be released from all obligations under such lease with respect to the lands, zones or horizons surrendered, but no such surrender shall release such lessee from any liability for breach of any monetary obligation of the lease with respect to which such lessee is in default at the time of the filing of such surrender.
7 Del. C. § 6125