Section 556.1100 - How does a lease expire?(a) Your oil and gas lease will automatically expire at the end of its primary term unless you have taken action, as set forth in § 556.601 , to maintain the lease beyond the primary term.(b) Your sulfur lease will automatically expire at the end of its primary term unless you have taken action, as set forth in § 556.603 , to maintain the lease beyond the primary term.