For the purpose of conservation of the natural resources of all or part of any oil or gas pool, field, reservoir, or like area, lessees (including representatives) of the pool, field, reservoir, or like area may unite with each other, or jointly or separately with others, in collectively adopting and operating under a unit agreement for all or part of the pool, field, reservoir, or like area (whether or not any other part of the oil or gas pool, field, reservoir, or like area is already subject to any cooperative or unit plan of development or operation), if the Secretary determines the action to be necessary or advisable in the public interest. In determining the public interest, the Secretary should consider, among other things, the extent to which the unit agreement will minimize the impact to surface resources of the leases and will facilitate consolidation of facilities.