Comparison of the Origin and Secondary Processes of Oils from the Polish Outer Carpathians, their Paleozoic-Mesozoic Basement, the U.S. Bighorn and Wind River Basins
D. Wieclaw, M.J. Kotarba and N. Kmiecik
Event name: 80th EAGE Conference and Exhibition 2018
Session: Poster: Source Rocks and Petroleum Systems A
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 741.69Kb )
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The study is focused on the comparison of the geochemical properties of oils occurring within the reservoirs of the Polish Outer Carpathians (POC), the Paleozoic-Mesozoic Basement (PMB) of POC and the Carpathian Foredeep in Poland, and reservoired within the Bighorn and Wind River basins in the U.S. Rocky Mountains. The geochemical studies of totally 139 oil samples were conducted in order to understand the processes of petroleum generation, trapping, and secondary alteration in these basins, which were formed during the Alpine and Laramide orogenic stages, and range in reservoir age and lithostratigraphy, and source rock age, lithostratigraphy and genetic type from Ordovician to Early Miocene. In both USA basins two oil families generated from Type IIS kerogen deposited in anoxic carbonates, and Type II or II/III kerogen dispersed in sub-oxic shales were recorded. Some biodegradation processes are evident in both families. Oils collected from POC and most of the oils from PMB are generated from low-sulphur Type II or II/III kerogen deposited in anoxic shales. In PMB oils generated from Type IIS kerogen were also recorded. Light or moderate biodegradation is evident in many oils accumulated in the POC and only in single oil reservoired in the PMB.