Mont. Code § 77-3-430
Nothing contained in this or in prior related laws prevents the board from entering into agreements for the pooling of acreage with others for unit operations for the production of oil or gas or both and the apportionment of oil or gas royalties or both on an acreage or other equitable basis and from modifying leases with respect to delay rentals, delay drilling penalties, and royalties in accordance with such pooling agreements and such unit plans of operation. However, such agreements may not change the percentage of royalties to be paid to the state from the percentages as fixed in its leases. The board may modify existing pooling and unit agreements so as to commit the state lands included therein for as long as the unitized substance or substances for which the state lands are committed is produced from any lands in the unit.
§ 77-3-430, MCA