Hydrocarbon Source Potential of Lacustrine Rift-Stage Successions of South American Sedimentary Basins
M. R. Mello, T. Takaki, and J. M. Guthrie
In recent years, various investigations of sedimentary basins in, China, Brazil and Indonesia, have shown the importance of lacustrine depositional environments with regard to their hydrocarbon potential.
In this study, a suite of oils and organic-rich lacustrine rocks of Triassic and Cretaceous ages from South America, were analysed aiming the characterization of a variety of lacustrine depositional environments therein, such as lacustrine freshwater, fresh/brackish-water, brackish/saline, saline and hypersaline waters, using molecular geochemistry. The development of such depositional settings are discussed with respect to their impact on hydrocarbon exploration.
A total of 50 rock and 20 oils samples, known to be derived from prominent lacustrine source rocks and oil fields were selected and analysed for bulk geochemistry, biological marker and stable carbon isotopes, in an attempt to characterize the relationship between hydrocarbon potential and the depositional paleoenvironments.
The integration of all data allowed the characterization of the most important lacustrine petroleum systems in South American which represent about 10% of the known Brazilian hydrocarbons reserves.
With respect to the oil-in-place volume and production, the most significant one is the Early Cretaceous rift system associated with the siliciclastic reservoirs deposited in Lacustrine environments.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California