(1) Any lease may be assigned, mortgaged, sublet, or otherwise transferred as to a divided or undivided interest therein to any qualified applicant subject to the approval of the department. The lessee shall execute an assignment approved by the commissioner. A transfer of a separate zone or deposit under any lease or a part of a legal subdivision shall be considered an assignment and is subject to the approval of the department. All approved assignments shall take effect as of the first day of the lease month following the date of approval. A separate assignment fee is required for each separate lease in which an interest is assigned.

(2) Assignments of undivided interests in a lease or changes in controlling lease interest shall not create new leases or new obligations and shall be subject to the approval of the department. The approval of these assignments, a designation of a single agent or a power of attorney executed by all lessees shall be filed with the department and an acceptable agreement adequate to protect the state's interest including a designation of the lessee shall be executed and filed with the department.

(3) Any divided interest or partial assignment of a geographically distinct subdivision of a lease shall segregate the assigned and retained portions thereof and upon approval of such assignment by the commissioner, create a new lease as to the assigned lands. The rights and obligations of the lessees under the retained portion and the assigned portion of the original lease are separate and distinct but are identical as to terms and conditions. Execution of the assignment shall release or discharge the assignor from all obligations thereafter accruing with respect to the assigned lands. Such segregated leases shall continue in full force and effect for the primary term of the original lease.

(4) Owners of cost-free interests such as overriding royalties, where authorized by the department, shall not be considered lessees and shall be subject to the rights of the department against the lessee. All state assignment documents shall contain provisions which subject any cost-free interests created by an assignment to the authority of the commissioner to require the proper parties to suspend or modify such overriding royalties or payments out of production in such a manner as may be reasonable when and during such periods of time as they may constitute an undue economic burden upon the reasonable development and operations of such lease.

(5) The approval of any assignment shall not waive compliance with any terms and conditions of the original lease. The department may subject the assignment to special requirements or conditions to correct any noncompliance with the original lease. Upon approval of any assignment, the assignee or sublessee shall be bound by the terms of the original lease to the same extent as if such assignee or sublessee were the original lessee.