Source rock potential of the Miocene sedimentary rocks in the Carpathian Foredeep of the Czech Republic

Abstract

We determine the organic matter content, its thermal maturity, genetic type, and source rock potential of the Miocene sedimentary rocks in the Czech Carpathian Foredeep. In the Czech Republic the Carpathian Foredeep represents a peripheral foreland basin formed due to the tectonic emplacement and loading of the Alpine-Carpathian Thrust Wedge onto the passive margin of the Bohemian Massif. Random vitrinite/huminite reflectance measurements and maceral analyses were performed on 25 samples from the Carpathian Foredeep succession. Additionally, results of 135 TOC content measurements, 141 Rock-Eval pyrolysis analyses and 27 vitrinite reflectance measurements were used to evaluate the regional distribution and depth trends for the entire Carpathian Foredeep. The thermal maturity of organic matter is between the immature part and peak of the oil window (Tmax = 413–448°C). Beneath the Western Carpathian Thrust Belt, the thermal maturity reaches higher values (Rr = 0.43–0.58%, Tmax = 429–448°C). The hydrocarbon generation potential is poor or fair, even if the total organic carbon values indicate good or even very good source rock potential. This is mainly due to the prevailing gas-prone Type III kerogen. The best source rocks were observed in the Miocene strata of the southern and central segments of the area discussed.