Palaeoenvironmental and Geodynamic Controls on Global Source Rock Intervals

Major intervals of source rock deposition punctuate the rock record. Klemme and Ulmishek (1991) described these in detail while discussing the contribution of each identified source rock to global petroleum reserves. On a global scale the overriding controls on organic matter production and preservation are environmental setting, tectonics, and climate. Therefore, understanding the temporal and spatial distribution of organic facies within a palinspastically restored and sequence stratigraphically constrained global environmental framework allows us to predict source rock deposition in frontier regions away from good data control.

Our global petroleum systems database comprises >2 million pieces of published source rock data, which we use to define areas of organic enrichment and to establish, with confidence, gross depositional environment maps for biostratigraphically defined surfaces. By applying a global geodynamic model to these maps and data we can restore sedimentary basins to their syn-depositional configuration, and investigate major controls on organic-rich facies deposition such as structural silling and fluvial input.

Climatic controls and their relationships to weathering and upwelling regimes are also investigated by applying a palaeoclimate model to the global geodynamic model. In order to demonstrate the power of this approach, the Frasnian-Famennian interval is studied. Simulation of summer ocean circulation predicts coastal and equatorial upwelling in western Laurentia, which correlates with proven source rock accumulations in present-day North America.

Having the ability to examine the distribution of organic-rich facies in a global setting improves our understanding of the development of known organic-rich facies and allows us to interpret potential source rocks in frontier areas with low data density.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California