About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

CSPG Special Publications


Facts and Principles of World Petroleum Occurrence — Memoir 6, 1980
Pages 996-997
Symposium Abstracts

An Approach to Assessment of Potential Petroleum Source Rocks, Canadian Arctic Islands: Abstract

T. G. Powell1

An investigation has been made of the hydrocarbon source rock potential of Mesozoic and Paleozoic sedimentary rocks of the Canadian Arctic Islands. Four facies of organic metamorphism have been recognized in the Sverdrup Basin, namely undermature, marginally mature, mature and overmature. Amorphous organic matter begins to generate hydrocarbons in the marginally mature facies and reaches a maximum in the mature facies. Significant hydrocarbon generation occurs in woody herbaceous organic matter only in the mature facies. Cracking of liquid hydrocarbons and kerogen to form gas occurs in the overmature zone. In the Sverdrup Basin the onset of the marginally mature zone occurs at approximately 1 500 m (5 000 ft) maximum burial depth, whereas the mature to overmature transition occurs in the vicinity of 4 300 m (14 000 ft) maximum burial depth. Hydrocarbon yields (mg of hydrocarbons per gram of organic carbon) are used as a basis for assessment of source rock quality. Either due to lack of maturity or source organic matter type, the majority of the strata in the Sverdrup Basin are likely only to have yielded gas. The Schei Point Formation (Middle-Upper Triassic) consistently contains organic matter suitable for oil generation. However, the amounts of oil that may have been expelled are relatively small.

All the wells in the Franklinian Geosyncline commence in the mature or overmature facies. The finegrained sediments of the Devonian elastic wedge and the Lower Paleozoic graptolitic shale facies can have excellent source potential for oil. The position of the mature to overmature transition is the governing factor in determining the hydrocarbon product (oil or gas). The Bird Fiord Formation consists of repetitive cycles of sandstone and shale and forms optimum conditions for drainage. However, the low organic carbon content of the shales means that the volume of migrateable oil is low.

Acknowledgments and Associated Footnotes

1 Geological Survey of Canada, 3303 - 33 Street N.W., Calgary, Alberta T2L 2A7

Copyright © 2009 by the Canadian Society of Petroleum Geologists