Evidence for a Jurassic Source Rock in the Guiana-Suriname Basin

Abstract

Mid to upper Jurassic age source rocks, and their related petroleum systems, have played a major role in generating some of the world's largest oil and gas fields. Middle-Upper Jurassic source rocks are mainly found in the Middle East (Hanifa-Naokelkan-Sargelu-Dukhan formations), the Caspian region (various formation names), West Siberia (Bazhenov Formation), North Sea (Kimmeridgian Clay), and Gulf of Mexico (Haynesville Shale). These rocks are predominantly marine shale and marly limestone with kerogen types II and III, and have charged Upper Jurassic to Cretaceous oil and gas reservoirs The Guyana – Suriname basin displays the geologic elements described above. Mid to late Jurassic age graben structures, filled with syn-rift sediments, overlain by post rift, passive margin, prograding marine sediments from mid Cretaceous to present can be identified on seismic lines offshore Suriname. None of these graben structures have been penetrated by wells. The questions therefore are; ‘Is there mature source rock and related petroleum systems within the grabens of the Guyana – Suriname Basin similar to that of the North Sea graben and the Kimmeridgian Petroleum System?” “How much hydrocarbons has been generated” “What are the implications for the Suriname part of the Guiana Basin” Analysis of crude oil in the Upper Cretaceous reservoirs onshore Suriname revealed the presence of a possible Mid Jurassic Source Rock. In addition, offshore well A2-1, drilled on the Demerara Plateau in the Guyana – Suriname basin, penetrated pre rift lower to middle Jurassic sediments and confirmed the presence of non-graben related Jurassic source rocks in the basin. Similarly, the Takutu Graben of onshore Guyana, interpreted as a failed arm of the early Jurassic North Atlantic rifting, has proven source rock and a unique Petroleum System within the graben. The evidence presented indicate: The Jurassic source rock is mature for hydrocarbon generation. The Jurassic source rock has the generated tremendous amounts of hydrocarbons The Jurassic source rock in the Suriname part of the Guiana basin can play an important role within the oil and gas industry for Suriname.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017