--> Abstract: Organic Maturity, Conditions of Veining and Hydrocarbon Migration in the Barrandian Basin (Lower Paleozoic), Czech Republic, by V. Suchy, I. Rozkosny, and P. Dobes; #90942 (1997).

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Abstract: Organic Maturity, Conditions of Veining and Hydrocarbon Migration in the Barrandian Basin (Lower Paleozoic), Czech Republic

SUCHY, VACLAV, IVAN ROZKOSNY, and PETR DOBES

The Ordovician to Middle Devonian Barrandian basin of central Bohemia contains more than 6 km thick sequence of marine sediments that has never been investigated systematically for its hydrocarbon potential. Silurian sedimentary units appear to be especially rich in organic carbon and exhibit numerous small-scale accumulations of bitumens and oils. The level of diagenetic transformation of the Silurian strata was established throughout the basin by means of organic petrography, clay mineralogy and fluid inclusion studies.

Reflectance of vitrinoid macerals as the most significant maturity parameter varies between 0.93% to 1.38% Rm, which points to the maturation within the oil/gas window. Illite crystallinity (I.C.) data from adjacent clayey sediments range from 2.30 to 0.48 (delta degrees 2 theta) and suggest that the rocks have undergone medium to high levels of diagenesis. Several generations of tectonic and hydraulic veins filled with semi-solid bitumen and oil-inclusion-rich calcite and quartz are evidence that the hydrocarbons once migrated through the sediments. Vitrinite paleogeothermometry and fluid inclusion data suggest diagenetic temperatures between 90 - 160 degrees C. Diagenetic modeling shows that approximately 3 km of presumably post-Givetian sediments, which have since been eroded, were responsible for these burial alterations.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria