Montney Formation

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Montney Formation
Stratigraphic range: Anisian
Montney FM.JPG
Type Geological formation
Underlies Doig Formation, Fernie Group
Overlies Belloy Formation
Area 127,000 acres (510 km2)[1]
Thickness up to 280 metres (920 ft)[2]
Lithology
Primary Siltstone and shale
Other Dolomitic siltstone, sandstone
Location
Coordinates 56°34′18″N 121°13′19″W / 56.57159°N 121.2219°W / 56.57159; -121.2219 (Buick Creek No. 7 well)Coordinates: 56°34′18″N 121°13′19″W / 56.57159°N 121.2219°W / 56.57159; -121.2219 (Buick Creek No. 7 well)
Region British Columbia, Alberta
Country  Canada
Type section
Named for Montney, British Columbia
Named by J.H. Armitage, 1962

The Montney Formation is a stratigraphical unit of Lower Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta.

It takes the name from the hamlet of Montney and was first described in Texaco's Buick Creek No. 7 well by J.H. Armitage in 1962.[3] The well was drilled 41 kilometers (25 mi) north of Fort St. John, immediately east of the Alaska Highway.

Lithology[edit]

The formation is composed of siltstone and dark grey shale, with dolomitic siltstone in the base and fine grained sandstone towards the top.[2] The facies is shaley in the north and west of the extent (Fort St. John), silty in the center (Dawson Creek and Pouce Coupe areas) and becomes coarser (sandy) in western Alberta (Valleyview area).[4]

Oil and gas production[edit]

The Montney Formation is a major shale gas and shale oil resource with reserves of 449 trillion cubic feet of marketable natural gas, 14,521 million barrels of marketable natural gas liquids (NGLs) and 1,125 million barrels of oil. [5] [6]

Gas is produced from the Montney Formation in the Peace River Country in British Columbia, by Petronas among others,[1] and oil is produced from the formation in northern Alberta.[4] Horizontal drilling and extensive fracturing process is necessary to have the fluid flow through the low permeability siltstone. Shale gas extraction emerged in the late 2000s in the distal facies of the formation's western extent.

Distribution[edit]

The Montney Formation reaches maximum thickness in the foothills of the northern Canadian Rockies at 280 meters (920 ft), and thins out towards the north up to the Fort Nelson area and towards the east to Peace River.

Relationship to other units[edit]

Montney Formation is unconformably overlain by Jurassic or Cretaceous beds such as the Doig Formation or Fernie Group and unconformably underlain by the Permian or Carboniferous strata such as the Belloy Formation.

References[edit]