Unit Operation in the Rock River Field, Wyoming

Abstract

The discovery well in the Rock River field, in Carbon County, Wyoming, camein May 1, 1918. The field is on a large anticline having more than 1500 ft. ofclosure and production is obtained from three sands of the Dakota group. At itspeak, production approximated 10,000 bbl. daily and is now averaging 2200 bbl.Total production to Jan. 1, 1930, exceeded 12,500,000 barrels. So far as known to the writer, Rock River was the first light oil field in theRocky Mountain region to be produced under what we now term unit operation.Though this type of operation was not popularly acclaimed by the oil industry, the Federal Government and the public until many years after the inception ofdevelopment at Rock River, the officials of the Ohio Oil Co. when acquiringthis property were fully cognizant of the economies to be effected by unitownership and the consequent elimination of competitive drilling and producingof wells, and had this in mind at the time. Thus unit management was introducedin this field at an early date by this company. Area and Management Fig. 1 shows the location of all wells drilled on the Rock River structure andthe outline of the productive area as now defined, which amounts to 1380 acres.The hachured line indicates the area now under unit ownership; originally amuch larger area was so owned but leases have been canceled as progressivedevelopment indicated their lack of oil. The management and operation of the entire productive area is handled by theOhio Oil Co., which owns the majority working interest. The Continental Oil Co.with a 20 to 35 per cent. interest in much of this acreage, and smallerinterests owned by others in some of the leases, constitute the remainder ofthe ownership.