(a) Unitization of leases. The Osage Tribal Council and Lessee or Lessees, may, with the approval of the Superintendent, unitize or merge, two or more oil or oil and gas leases into a unit or cooperative operating plan to promote the greatest ultimate recovery of oil and gas from a common source of supply or portion thereof embracing the lands covered by such lease or leases. The cooperative or unit agreement shall be subject to the regulations in this part and applicable laws governing the leasing of the Osage Mineral Estate. Any agreement between the parties in interest to terminate a unit or cooperative agreement as to all or any portion of the lands included shall be submitted to the Superintendent for his approval. Upon approval the leases included thereunder shall be restored to their original terms: Provided, That for the purpose of preventing waste and to promote the greatest ultimate recovery of oil and gas from a common source of supply or portion thereof, all oil leases, oil and gas leases, and gas leases issued heretofore and hereafter under the provisions of the regulations in this part shall be subject to any unit development plan affecting the leased lands that may be required by the Superintendent with the consent of the Osage Tribal Council, and which plan shall adequately protect the rights of all parties in interest including the Osage Mineral Estate.

(b) Assignments. Approved leases or any interest therein may be assigned or transferred only with the approval of the Superintendent. The assignee must be qualified to hold such lease under existing rules and regulations and shall furnish a satisfactory bond conditioned for the faithful performance of the covenants and conditions thereof. Lessee must assign either his entire interest in a lease or legal subdivision thereof, or an undivided interest in the whole lease: Provided, That when an assignment covers only a portion of a lease or covers interests in separate horizons such assignment shall be subject to both the consent of the Osage Tribal Council and approval of the Superintendent. If a lease is divided by the assignment of an entire interest in any part, each part shall be considered a separate lease and the assignee shall be bound to comply with all the terms and conditions of the original lease. A fully executed copy of the assignment shall be filed with the Superintendent within 30 days after the date of execution by all parties. If requested within the 30-day period, the Superintendent may grant an extension of 15 days. A filing fee of $10 shall accompany each assignment.

(c) Overriding royalty. Agreements creating overriding royalties or payments out of production shall not be considered as an interest in a lease as such term is used in paragraph (b) of this section. Agreements creating overriding royalties or payments out of production are hereby authorized and the approval of the Department of the Interior or any agency thereof shall not be required with respect thereto, but such agreements shall be subject to the condition that nothing in any such agreement shall be construed as modifying any of the obligations of Lessee under his lease and the regulations in this part. All such obligations are to remain in full force and effect, the same as if free of any such royalties or payments. The existence of agreements creating overriding royalties or payments out of production, whether or not actually paid, shall not be considered in justifying the shutdown or abandonment of any well. Agreements creating overriding royalties or payments out of production need not be filed with the Superintendent unless incorporated in assignments or instruments required to be filed pursuant to paragraph (b) of this section. An agreement creating overriding royalties or payment out of production shall be suspended when the working interest income per active producing well is equal to or less than the operational cost of the well, as determined by the Superintendent.

(d) Drilling contracts. The Superintendent is authorized to approve drilling contracts with a stipulation that such approval does not in any way bind the Department to approve subsequent assignments that may be provided for in said contracts. Approval merely authorizes entry on the lease for the purpose of development work.

(e) Combining leases. The lessee owning both an oil lease and gas lease covering the same acreage is authorized to convert such leases to a combination oil and gas lease.