ABSTRACT

Production from the Bakken Formation was established in North Dakota in 1953 when Stanolind Oil and Gas Corp. drilled and completed the #1 Woodrow Starr, SWSE Sec. 21, T152N, R94W in Antelope field. Producing wells within Antelope field perforate portions of the Bakken Formation, the localized "Sanish sand" at the top of the Three Forks Formation, or both. Production is independent of lithology; the well may be a good producer regardless of the presence of the "Sanish sand."

Outside of Antelope field, the Bakken Formation was not considered a primary target because it was generally impermeable, and produced primarily from natural fractures. Following the initial discovery, development of Bakken oil proceeded slowly. The next discovery occurred in 1961, when Shell Oil Company used seismic methods to discover Elkhorn Ranch field. The Shell Oil Company #41X-5-l Government, NENE Sec. 5, T143N, R101W was drilled as an Ordovician Red River test but recovered oil from the Bakken on a drill stem test The well was subsequently completed in the Bakken and yielded 136 BOPD. The well flowed an average of 50 BOPD until 1964, when it was plugged and abandoned due to a collapsed casing. No further development of Bakken reservoirs occurred in Elkhorn Ranch field until February 1977 when Gulf Oil Corporation completed the #1-5 Gulf-Sunbehm USA, NWNW Sec. 5, T143N, R101W.

The late 1970's was an active period for Bakken development. During this time, interest was directed towards the depositional limit of the Bakken Formation in southwestern North Dakota. Reservoirs developed in this area were known for having high pressures, producing little or no water and having gradual decline rates. Attention was directed toward this area again in 1987, when Meridian Oil, Inc. drilled and completed the first horizontal hole in the Bakken Formation.

The Bakken Formation has produced in 50 fields in North Dakota; 34 of these fields are still producing. A total of 20,992,194 barrels of oil have been produced as of March 1990; 76.2% of the oil has come from three fields: Antelope, Elkhorn Ranch, and Buckhorn. Bakken production is increasing again as a result of the new horizontal play. Horizontal wells produced an average of 144 BOPD in March 1990. Cumulative production from the horizontal wells through March 1990 was 1,700,997 barrels of oil.