The Horn River Formation (also Horn River Shale) is a stratigraphical

Stratigraphy

Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....

 unit of Devonian

Devonian

The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 age

Geochronology

Geochronology is the science of determining the age of rocks, fossils, and sediments, within a certain degree of uncertainty inherent to the method used. A variety of dating methods are used by geologists to achieve this, and schemes of classification and terminology have been proposed...

 in the Western Canadian Sedimentary Basin

Western Canadian Sedimentary Basin

The Western Canadian Sedimentary Basin is a vast sedimentary basin underlying of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. It consists of a massive wedge of sedimentary rock...

.

It takes the name from the Horn River

Horn River

The Horn River is a river in the Northwest Territories of Canada. It is a major tributary of the Mackenzie River.The river gives the name to the Horn River Formation, a shale deposit of the Western Canadian Sedimentary Basin...

, a tributary of the Mackenzie River

Mackenzie River

The Mackenzie River is the largest river system in Canada. It flows through a vast, isolated region of forest and tundra entirely within the country's Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories...

, and was first described in outrop on the banks of Horn River in the Northwest Territories

Northwest Territories

The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...

 (at the time District of Mackenzie

District of Mackenzie

The District of Mackenzie was a regional administrative district of Canada's Northwest Territories. The district consisted of the portion of the Northwest Territories directly north of British Columbia, Alberta, and Saskatchewan on Canada's mainland....

) by Whittaker in 1922. It was redefined in 1963 in the sub-surface of the Fort Nelson

Fort Nelson, British Columbia

Fort Nelson is a town of approximately 5000 residents in British Columbia's northeastern corner. It is the administrative centre of the newly formed Northern Rockies Regional Municipality, a first for BC. The majority of Fort Nelson's economic activities have historically been concentrated in the...

 area (well Fort Nelson a-95-J/94-J-10) by F.F. Gray and J.R. Kassube.

Lithology

The Horn River Formation is composed of argillaceous bitumenous limestone, and dark siliceous and calcareous shale

Shale

Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...

.

Hydrocarbon production

Shale gas

Shale gas

Shale gas is natural gas produced from shale. Shale gas has become an increasingly important source of natural gas in the United States over the past decade, and interest has spread to potential gas shales in the rest of the world...

 is produced from the siliceous shale of the Horn River Formation in north-eastern British Columbia

British Columbia

British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, in the Greater Sierra field

Greater Sierra (oil field)

Greater Sierra is a large oil and gas field in northeastern British Columbia, Canada.It is located east and north from the town of Fort Nelson, extending to the Alberta and Northwest Territories borders .Drilling activity takes place largely during the winter months, when the otherwise soft muskeg...

, north of Fort Nelson

Fort Nelson, British Columbia

Fort Nelson is a town of approximately 5000 residents in British Columbia's northeastern corner. It is the administrative centre of the newly formed Northern Rockies Regional Municipality, a first for BC. The majority of Fort Nelson's economic activities have historically been concentrated in the...

. Horizontal drilling and fracturing

Hydraulic fracturing

Considerable controversy surrounds the current implementation of hydraulic fracturing technology in the United States. Hydraulic fracturing, or fracking, is the process of utilizing pressurized water, or some other liquid, to fracture rock layers and release petroleum, natural gas, or other...

 techniques are used to extract the gas from the low permeability shales. The original-gas-in-place volumes are estimated to be up to 500 Tcf , making it the third largest North American natural gas accumulation discovered prior to 2010. Companies involved in the extraction of natural gas from the Horn River Shale include EnCana

EnCana Corporation

Encana Corporation is one of North America's largest natural gas producers, with about 95 percent of its production being natural gas. Its strategy is to be the lowest-cost, highest-growth senior natural gas producer in North America. The company produced approximately of natural gas in 2010.The...

, Apache

Apache Corp.

Apache Corporation is an American independent oil and gas corporation. It is headquartered in 1 Post Oak Central in the Uptown district of Houston, Texas....

, EOG

EOG Resources

EOG Resources is a Fortune 500 company with its headquarters in the Heritage Plaza building in downtown Houston, Texas. The company is one of the largest independent oil and natural gas companies in the United States with proven reserves in the United States, Canada, Trinidad and Tobago, the United...

, Stone Mountain Resources, Exxon

ExxonMobil

Exxon Mobil Corporation or ExxonMobil, is an American multinational oil and gas corporation. It is a direct descendant of John D. Rockefeller's Standard Oil company, and was formed on November 30, 1999, by the merger of Exxon and Mobil. Its headquarters are in Irving, Texas...

, Quicksilver Resources

Quicksilver Resources

Quicksilver Resources Inc. is an oil and gas exploration and production company based in Fort Worth, Texas. It has operations in the United States and Canada....

, Nexen

Nexen

Nexen Inc. is an energy company based in Calgary, Alberta, Canada.-History:Nexen started in 1969 under the name "Canadian Occidental Petroleum Ltd.", aka CanOxy, and was 80% owned by Occidental Petroleum, a Los Angeles-based oil company...

 and Devon Energy.

Distribution

The Horn River Formation occurs in north-eastern British Columbia

British Columbia

British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

 and extends to Great Slave Lake

Great Slave Lake

Great Slave Lake is the second-largest lake in the Northwest Territories of Canada , the deepest lake in North America at , and the ninth-largest lake in the world. It is long and wide. It covers an area of in the southern part of the territory. Its given volume ranges from to and up to ...

 in the Northwest Territories

Northwest Territories

The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...

, where it outcrops. It reaches a maximum thickness of 320 metres (1,049.9 ft) in the sub-surface of the Fort Nelson

Fort Nelson, British Columbia

Fort Nelson is a town of approximately 5000 residents in British Columbia's northeastern corner. It is the administrative centre of the newly formed Northern Rockies Regional Municipality, a first for BC. The majority of Fort Nelson's economic activities have historically been concentrated in the...

 area.

Relationship to other units

The Horn River Formation is overlain by the Fort Simpson Formation

Fort Simpson Formation

The Fort Simpson Formation is a stratigraphical unit of Devonian age in the Western Canadian Sedimentary Basin.It takes the name from the settlement of Fort Simpson, and was first described in well Briggs Turkey Lake No. 1 by A.E...

 and underlain by the limestones of the Lonely Bay Formation, Nahanni Formation

Nahanni Formation

The Nahanni Formation is a stratigraphical unit of Givetian age in the Western Canadian Sedimentary Basin.It takes the name from Nahanni Butte, a proeminent ridge at the confluence of the South Nahanni River and Liard River, and was first described in outcrop on the south face of the mountain by C.O...

 or Pine Point Formation

Pine Point Formation

The Pine Point Formation is a stratigraphical unit of Givetian age in the Western Canadian Sedimentary Basin.It takes the name from Pine Point, a promontory on the south shore of the Great Slave Lake, west of Fort Resolution, and was first described in outcrop on the shore of the lake between Pine...

.

It is equivalent to the Slave Point Formation

Slave Point Formation

The Slave Point Formation is a stratigraphical unit of Middle Devonian age in the Western Canadian Sedimentary Basin.It takes the name from Slave Point, a promontory on the north-west shore of the Great Slave Lake, and was first described in outcrop on the southern shore of the lake and along the...

. It includes the Muskwa Formation

Muskwa Formation

The Muskwa Formation is a stratigraphical unit of Frasnian age in the Western Canadian Sedimentary Basin.It takes the name from Muskwa River, and was first described in the Western National Gas Fort Nelson a-95-J/94-J-10 well by F.F. Gray and J.R. Kassube, in 1963.-Lithology:The Muskwa Formation is...

, and the Waterways Member of the Hay River Formation in the Northwest Territories

Northwest Territories

The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...

. It includes the pinnacle reef

Reef

In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....

s of the Horn Plateau Formation.

Sub-divisions

The Horn River Shale was divided into the following members, from top to base:

• Muskwa Member: bituminous, radioactive shale
• Otter Park Member: grey calcareous shale
• Evie Member: black silty limestone