(a) Lease segregation occurs when:

(1) A portion of a lease is committed to a unit agreement while other portions are not committed; or

(2) Only a portion of a lease remains in a participating area when the unit contracts. The portions of the lease outside the participating area are eliminated from the unit agreement and segregated as of the effective date of the unit contraction.

(b) BLM will assign the original lease serial number to the portion within the agreement. BLM will give the lease portion outside the agreement a new serial number, and the same lease terms as the original lease.