Journal of Petroleum Geology, Vol.17, No.1, pp. 5-38, 1994

©Copyright 2000 Scientific Press, Ltd.

BASIN RICHNESS AND SOURCE ROCK DISRUPTION-
A FUNDAMENTALRELATIONSHIP?

L. C. Price*

* USGS, Denver Federal Centre, Denver, CO. 80225. USA.

Abstract

Primary petroleum migration (expulsion from source rocks) remains the least understood parameter controlling the genesis of oil deposits. In spite of this lack of understanding, many petroleum geochemists (including this Author) have previously considered expulsion from organic-rich, mature source rocks to be very efficient. This viewpoint results from Rock-Eval analyses of organic-rich source rocks, analyses which demonstrate a loss of hydrocarbon (HC) generation capacity, by significant reduction in Rock-Eval hydrogen indices, as such rocks are progressively buried in sedimentary basins. However, this progressive loss of HC generation capacity is not matched by numerically-equivalent increases either in Soxhlet-extractable HCs or the Rock-Eval S1 pyrolysis peak. Thus, we conclude that almost all generated HCs have migrated from the source rocks.