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Updated June 2021

Quantifying Alberta’s resource endowment and maintaining the AER’s evolving reporting system require an understanding of the Western Canada Sedimentary Basin. The Geological Atlas of the Western Canada Sedimentary Basin describes Alberta’s geological history. The geological origin and structure of Alberta’s strata ultimately determine the type and extent of Alberta’s energy resources. Information on Alberta’s stratigraphic succession of geological units and geological timescale are found in the Alberta Table of Formations.

Petroleum Systems

The exploration, development, and regulation of petroleum resources need to account for both the different petroleum systems within a sedimentary basin and for the different ways petroleum is trapped in rocks.

Petroleum is generated in a source rock as bitumen, oil, natural gas, or a mixture. It can remain in the source rock or migrate to inorganic host rock. It can occupy the pores and fractures in the rock or be a component of organic material. A petroleum system is the linked geological assemblage of all source rocks plus associated reservoirs and traps. Alberta has nine petroleum systems (as defined by the Alberta Geological Survey).

Coalification also generates natural gas. Treating coal as a source rock brings the total number of potential petroleum sources at the geological formation level in Alberta to at least 14. Among global sedimentary basins, this is considered to be a large number of petroleum systems and is one reason why Alberta has such a large petroleum and coal endowment.

Geological Plays

Within each petroleum system, the AER has defined geological plays to help assess reserves and resources in Alberta.

A geological play is a set of known or postulated accumulations of petroleum (pools and deposits) within a petroleum system that share the same geological, geographical, and temporal properties, such as source rock, migration pathways, timing, trapping mechanism, mode of occurrence, and hydrocarbon type.

These organizations also use the play concept for resource estimation:

  • the Geological Survey of Canada
  • the Canadian Gas Potential Committee
  • the United States Geological Survey (see their World Oil and Gas Resource Assessments page)

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