Source rock prediction: Carpathian-Central Asia case study

Jan Golonka, Institute of Geological Sciences, Jagiellonian University, Oleandry2a, Krakow, 30-063, Poland, phone: 48-12-633-2270, fax: 48-12-633-2270, golonka@geos.ing.uj.edu.pl, Nataliya Y Bocharova, University of Texas at Arligton, Arlington, TX, Mary E Edrich, Mobil, Jouston, TX, Wolfgang Kiessling, Museum fur Naturkunde, Berlin, Germany, Michal Krobicki, University of Mining and Metallurgy, Krakow, Poland, Robert Pauken, Mobil, Dallas, TX, and William Wildharber, Mobil, Georgetown, TX.

Thirty-six Late Jurassic-Early Cretaceous regions were evaluated to obtain the source rocks prediction value (SRPV). The overall effectiveness three major processes (biologic productivity, depositional preservation, and non-dilution) including their subprocesses, was assigned a value between 1 and 5 (5 being most effective) by at least five experts and the results combined into an average value. The three values, one for each of the major processes, were multiplied together to produce a SRPV, range 1-125. The Source Potential Index (SPI) is a measure of cumulative petroleum potential defined as the maximum quantity of hydrocarbons (in metric tons) that can be generated within a column of source rock under 1 m2 of surface area. Average SPI measurements have been published for 6 Late Jurassic marine source rock sequences. These sequences are found in 5 independent Late Jurassic tectono-depositional provinces. These basins were part of the same tectono-depositional province in the Late Jurassic and SPI values were equal. SRPV's were assessed for each of the five independent areas and plotted against the measured SPI values to calibrate the method.

The Northern Tethyan Central Asia basin was ranked eighth, while the similar Carpathian basin ninth. The high organic productivity in these basins was caused by upwelling, as well as restricted conditions in the narrow rift basins. Self-contained petroleum systems consisting of source rocks, carbonate reservoirs and evaporitic seals contribute to the hydrocarbon reserves . Actual hydrocarbon production is ongoing in Afghanistan and Amu-Daria Province. Possibly Late Jurassic/Early Cretaceous rocks sourced some of Carpathian oils.

Africa, Middle East, Europe, Caspian and Black Sea Region (AAPG)
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