UNIT OPERATION OF OIL AND GAS FIELDS

In less than a century, petroleum has changed from "a peculiar liquid not necessary nor indeed suitable for the common use of man" I to a substance indispensable to the military security and economic prosperity of a modern nation. 2 Adjudication of claims to property rights in this invaluable substance has been greatly complicated by the circumstances of its occurrence. Petroleum is found in underground reservoirs consisting of porous strata filled with some mixture of oil, gas and water, all under pressure. The reservoirs are of limited volume 3 and may underlie any number or portions of surface leases. Drilling a well into the reservoir creates a low pressure point to which reservoir oil and gas move, the movements refusing, of course, to respect lease boundaries. 4 In adjusting property rights to oil and gas, the courts at first followed the "rule of capture," giving a property owner title to all oil and gas produced through well bores located on his land, regardless of the underground source. Each surface owner consequently was impelled to