|Three Forks Group|
Stratigraphic range: Famennian to Tournaisian
|Sub-units||Bakken Formation, Lyleton Formation, Big Valley Formation, Torquay Formation|
|Thickness||35 metres (110 ft) to 80 metres (260 ft)|
|Primary||Dolomite, mudstone, shale|
|Region||Western Canadian Sedimentary Basin, Williston Basin|
|Named for||Three Forks, Montana|
|Named by||A.C. Peale, 1893|
The Three Forks Group is a stratigraphical unit of Famennian age in the Williston Basin.
It takes the name from the city of Three Forks, Montana, and was first described in outcrop near the city by A.C. Peale in 1893 (for the Three Forks Shale).
The Three Forks Group is composed of Dolomite, mudstone and bituminous shale.
In the subsurface of the Williston Basin, the Three Forks is referred to as the Three Forks Formation, which lies between the Birdbear Formation below, and the Bakken Formation above.
Oil produced from the Three Forks Formation in the Williston Basin of North Dakota and south-eastern Saskatchewan is often included in production statistics with the overlying Bakken Formation. For instance, the Three Forks and Bakken were combined in estimates of potential production released by the United States Geological Survey on April 30, 2013. The estimate by the USGS projects that 7.4 billion barrels of oil can be recovered from the Bakken and Three Forks formations and 6.7 trillion cubic feet of natural gas and 530 million barrels of natural gas liquids using current technology.
The Three Forks Group reaches a maximum thickness of 80 metres (260 ft), but can be as thin as 35 metres (110 ft).
|Bakken Formation||Kinderhookian||bituminous shale||40 m (130 ft)|
|Lyleton Formation||Famennian||red dolomitic and silty shale, argillaceous dolomite||40 m (130 ft)|
|Big Valley Formation||Famennian||mudstone||40 m (130 ft)|
|Torquay Formation||Famennian||brown dolomite, shale||65 m (210 ft)|
The Three Forks Group conformably overlies the Saskatchewan Group and is disconformably overlain by the Madison Group.
It is equivalent to the sum of the Wabamun Group and Exshaw Formation in Alberta.
Williston is a city in and the county seat of Williams County, North Dakota, United States. The 2010 census gave its population as 14,716, and the Census Bureau gave the 2019 estimated population as 29,033, making Williston the sixth-largest city in North Dakota. The North Dakota oil boom is largely responsible for the sharp increase in population.
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The Williston Basin is a large intracratonic sedimentary basin in eastern Montana, western North Dakota, South Dakota, and southern Saskatchewan, that is known for its rich deposits of petroleum and potash. The basin is a geologic structural basin but not a topographic depression; it is transected by the Missouri River. The oval-shaped depression extends approximately 475 miles (764 km) north-south and 300 miles (480 km) east-west.
The Bakken Formation is a rock unit from the Late Devonian to Early Mississippian age occupying about 200,000 square miles (520,000 km2) of the subsurface of the Williston Basin, underlying parts of Montana, North Dakota, Saskatchewan and Manitoba. The formation was initially described by geologist J.W. Nordquist in 1953. The formation is entirely in the subsurface, and has no surface outcrop. It is named after Henry Bakken, a farmer in Tioga, North Dakota, who owned the land where the formation was initially discovered while drilling for oil.
The Madison Limestone is a thick sequence of mostly carbonate rocks of Mississippian age in the Rocky Mountain and Great Plains areas of western United States. The rocks serve as an important aquifer as well as an oil reservoir in places. The Madison and its equivalent strata extend from the Black Hills of western South Dakota to western Montana and eastern Idaho, and from the Canada–United States border to western Colorado and the Grand Canyon of Arizona.
The Bend Arch–Fort Worth Basin Province is a major petroleum producing geological system which is primarily located in North Central Texas and southwestern Oklahoma. It is officially designated by the United States Geological Survey (USGS) as Province 045 and classified as the Barnett-Paleozoic Total Petroleum System (TPS).
Enerplus Corporation is one of Canada’s largest independent oil and gas producers. The company holds oil and natural gas property interest in the United States and in western Canada, in the provinces of Alberta, British Columbia and Saskatchewan. The company is based out of Calgary, Alberta and trades on both the Toronto Stock Exchange and the New York Stock Exchange. It was Canada's first income trust.
Proven oil reserves in the United States were 43.8 billion barrels of crude oil as of the end of 2018, excluding the Strategic Petroleum Reserve. The 2018 reserves represent the largest US proven reserves since 1972. The Energy Information Administration estimates US undiscovered, technically recoverable oil resources to be an additional 198 billion barrels.
The Montney Formation is a stratigraphical unit of Lower Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta.
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The Elk Point Group is a stratigraphic unit of Early to Middle Devonian age in the Western Canada and Williston sedimentary basins. It underlies large area that extends from southern boundary of the Northwest Territories in Canada to North Dakota in the United States. It has been subdivided into numerous formations, many which host major petroleum and natural gas reservoirs.
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The Ellis Group is a stratigraphical unit of Bajocian-Oxfordian age in Alberta, Sakatchewan, Montana and Wyoming in the Western Canadian Sedimentary Basin. It takes the name from Fort Ellis, Montana, and was first described in outcrop in the Rocky Creek Canyon by A.C. Peale in 1893.
The Saskatchewan Group is a stratigraphical unit of Frasnian age in the Western Canadian Sedimentary Basin.
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Continental Resources, Inc. is an American petroleum and natural gas exploration and production company based in the Continental Oil Center in Oklahoma City. The company was founded by Harold Hamm in 1967 at the age of 21 as Shelly Dean Oil Company, originally named for Hamm's two daughters. In 1990, Shelly Dean re-branded itself as Continental Resources. It primarily used hydraulic fracturing and directional drilling to produce from low permeability formations.
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As of 2013 the Cline Shale, also referred to as the "Wolfcamp/Cline Shale", the "Lower Wolfcamp Shale", or the "Spraberry-Wolfcamp shale", or even the "Wolfberry", is a promising Pennsylvanian oil play east of Midland, Texas which underlies ten counties: Fisher, Nolan, Sterling, Coke, Glasscock, Tom Green, Howard, Mitchell, Borden and Scurry counties. Exploitation is projected to rely on hydraulic fracturing.
an organic rich shale, with Total Organic Content (TOC) of 1-8%, with silt and sand beds mixed in. It lies in a broad shelf, with minimal relief and has nice light oil of 38-42 gravity with excellent porosity of 6-12% in thickness varying 200 to 550 feet thick.
The Parshall Oil Field is an oil field producing from the Bakken Formation and Three Forks Formation near the town of Parshall, in Mountrail County, North Dakota. The field is in the Williston Basin. The field was discovered in 2006 by EOG Resources, which drilled, and now operates, most of the wells. It was the discovery of the Parshall Field that was largely responsible for the North Dakota oil boom. Parshall’s break-even price is at US$38/barrel, which is the lowest on the Bakken Formation; overall, Bakken’s break-even point is of US$62/barrel.
Whiting Petroleum Corporation is a company engaged in hydrocarbon exploration. It is organized in Delaware and headquartered in Denver, Colorado.
The doubling of the estimate resulted largely because of the first look at the Three Forks Formation in North Dakota, which the Geological Survey said contains 3.73 billion barrels of oil. Its reassessment of the Bakken Formation, which lies above Three Forks, showed 3.65 billion barrels, only a little more than a 2008 USGS estimate. The agency’s conclusion that the formations contain 6.7 trillion cubic feet of natural gas and 530 million barrels of natural gas liquids represented a tripling of previous estimates.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered volumes of 7.4 billion barrels of oil, 6.7 trillion cubic feet of associated/dissolved natural gas, and 0.53 billion barrels of natural gas liquids in the Bakken and Three Forks Formations in the Williston Basin Province of Montana, North Dakota, and South Dakota.