oa An Overview of Pre-Devonian Petroleum Systems – Unique Characteristics and Elevated Risks

Conventional hydrocarbon resources have been associated with pre-Devonian petroleum systems across the globe, including the Neoproterozoic–Infracambrian Huqf Supergroup of the Oman basin, the Riphean - Vendian sequences of East Siberia, the Cambrian of the Sirte basin, the Ordovician of the Tarim basin, and the Silurian Qasaiba of Saudi Arabia. Although individual accumulations can be quite significant (e.g., Hassi Messaoud has proven reserves of ~6.4 billion barrels), the relative importance of pre-Devonian-derived oils is limited compared to the global conventional resource-base. With growing interest in unconventional resources, the relative importance of these systems is expected to increase as plays such as the Ordovician Utica Shale of the Appalachian basin, the Cambrian of China, and the Silurian of Central and Eastern Europe develop.