Sen. Byron Dorgan says the U.S. Geological Survey is slated to release a study this week on the oil potential of the area known as the Bakken formation.
The shale formation encompasses some 25,000 square miles in North Dakota, Montana, Saskatchewan and Manitoba.
Dorgan says the study is to be released Thursday. He says it will estimate the amount of oil that is recoverable in the Bakken using current technology.
USGS 1995 study and current decline rates