Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.61701

(a) “Field” means an underground reservoir or reservoirs containing oil or gas, or both. Field also includes the same general surface area that is underlaid or appears to be underlaid by at least 1 pool. Field and pool have the same meaning if only 1 underground reservoir is involved. However, field, unlike pool, may relate to 2 or more pools.

(b) “Lessee” means lessees under oil and gas leases and also the owners of unleased lands or mineral rights having the right to develop them for oil and gas.

(c) “Oil and gas” means oil and gas as such in combination one with the other and also means oil, gas, casinghead gas, casinghead gasoline, gas distillate, or other hydrocarbons, or any combination or combinations of these substances, which may be found in or produced from a common source of supply of oil, gas, oil and gas, or gas distillate.

(d) “Pool” or “common source of supply” means a natural underground reservoir containing or appearing to contain a common accumulation of oil and gas. Each productive zone of a general structure that is completely separate from any other zone in the structure, or that may for the purposes of this part be declared by the supervisor to be completely separate, is included in the term pool or common source of supply. Any reference to a separately owned tract, although in general terms broad enough to include the surface and all underlying common sources of supply of oil and gas, shall have reference thereto only in relation to the common source of supply or portion thereof included within the unit area of a particular unit.

(e) “Supervisor” or “supervisor of wells” means the department as provided in part 615.  1

(f) “Unit area” means the formation or formations that are unitized and surface acreage that is a part of the unitized lands, as described in the plan for unit operations that is the subject of the supervisor's order as provided in section 61706.  2

(g) “Unit expense” means any and all cost, expense, or indebtedness incurred by the unit in the establishment of its organization or incurred in the conduct and management of its affairs or the operations conducted by it.

(h) “Unit production” means all indigenous oil and gas produced and saved from a unit area after the effective date of the order of the supervisor creating the unit, regardless of the well or tract within the unit area from which that oil and gas is produced.

(i) “Waste”, in addition to its ordinary meaning, means physical waste as that term is generally understood in the oil and gas industry. Waste includes all of the following: