Deep Gas Production in North Dakota's Williston Basin – Look Again
Randolph B. Burke
North Dakota Geological Survey, Bismarck, ND
Traditionally, the Williston Basin has not been thought of as a gas basin. However, 9% of the wells marketing deep gas in North Dakota have each produced over 12 BCF from an average depth of 13,230 feet, or 20% of deep gas wells have each produced over 5 BCF. One well has produced 80 BCF from the Ordovician Red River Formation. Production is mostly from retrograde condensate reservoirs, but some Ordovician/Cambrian wells are single phase gas reservoirs. Despite these high gas volumes from individual wells and a cumulative basin production of over 470 BCF, gas has never been a primary target in the basin.
Currently there are 20 fields producing gas from 40 wells and 7 different pools. There are an additional 87 wells in 31 fields that have produced gas from the same pools, but are not currently producing. The Ordovician Red River Formation is the largest producing formation followed by the Silurian Interlake Formation and then the Ordovician and Cambrian age Winnipeg Group and Deadwood Formation respectively. Lesser volumes of gas have been produced from the Silurian/Ordovician Stonewall Formation, and the Ordovician Gunton Formation. The majority of the gas has been produced from Amerada's Beaver Lodge Field on the Nesson Anticline.
In the past, low gas prices, limited gathering and processing systems, rugged badlands terrain, high hydrogen sulfide content in Ordovician gas, associated nitrogen and carbon dioxide gases, great drilling depth, and retention of leases by shallow oil production have combined to discourage development of this resource.