Reconstruction of Petroleum Systems Based on Integrated Geochemical and Geological Investigations: Selected Examples from the Middle Outer Carpathians in Poland
Irena Matyasik, Piotr S. Dziadzio, 2006. "Reconstruction of Petroleum Systems Based on Integrated Geochemical and Geological Investigations: Selected Examples from the Middle Outer Carpathians in Poland", The Carpathians and Their Foreland: Geology and Hydrocarbon Resources, Jan Golonka, Frank J. Picha
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A genetic analysis of oils and potential source rocks and their mutual correlation from three areas of hydrocarbon occurrence in three tectonic units (thrust nappes), Subsilesian, Silesian, and Dukla nappes of the Outer Carpathians in Poland, between Gorlice in the west and Krosno to the east, revises existing opinions on the genesis, migration, and accumulation of hydrocarbons in this part of the Carpathians.
One of the important hydrocarbon accumulations occurs in the Subsilesian unit (Weglowka oil field). Detailed geochemical studies show that the oil that accumulated in the Weglowka oil field is the same type as the oil that accumulated in the Potok anticline located about 10 km (6 mi) to the south in the Silesian nappe and derived from the same Oligocene Menilite shales source rock.
The oldest known source-prone interval in the Subsilesian nappe is the Verovice shales (Lower Cretaceous), which are likely to have produced the hydrocarbons found in the nearby Wola Jasienicka field located 8 km (5 mi) to the east from the Weglowka oil field.
The lower Istebna Shales (Upper Cretaceous) that occurred in the Silesian nappe in the area of Potok anticline could be good source rocks for oil. It is also possible that hydrocarbon generation occurred during several stages, and that mixing of oils derived from Menilite beds and Istebna Shales could have occurred in this area.
Similar studies have been made in the southern part of the study area around the oil-rich Gorlice region in the Silesian nappe. This study indicates that the oils accumulated in fields of this region were generated from the Menilite shales of the Dukla nappe, which occurred in tectonic windows in the Magura nappe.
Copyright ©2006. The American Association of Petroleum Geologists.
The tectonic relationship of the producing fields in the Weglowka–Potok clearly shows the occurrence of several major syncline around the fields. The deepest are to the south of the Wola Jasienicka and Potok fields, which could represent the generative kitchen for these fields during the different stages of Carpathian thrusting.
In addition, computer-generated simulations of oil generation in the vicinity of Gorlice and Potok areas suggest hydrocarbon generation and expulsion during the middle Miocene to Pliocene (Holocene).
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This volume of 30 chapters authored by 107 geologists and geophysicists from Austria, Czech Republic, Hungary, Poland, Romania, Slovakia, Ukraine, United Kingdom, and the USA provides a comprehensive and understandable account of geology and hydrocarbon resources of the entire Carpathian system from northeastern Austria to southern Romania, including the Neogene foredeep, the foreland platform both in front and beneath the thrust belt, the Carpathian thrust belt, and the late and post orogenic intermontane basins. Principal chapters on regional geology are supplemented by thematic contributions on geodynamic reconstructions, regional geophysical investigations, hydrocarbon systems, and case studies of major oil and gas fields. To date, close to 7 billion barrels of oil and more than 53 trillion cubic feet of natural gas have been produced from the entire Carpathian system. Additional new reserves may be found, especially at deeper structural levels below the Neogene foredeep and the thin-skinned Carpathian thrust belt. Seventeen chapters of Memoir 84 have been printed in full. The remaining chapters have been printed as abstracts only, with the full paper for all 30 chapters as .pdf files on the CD-ROM in the back of this publication. The publication is intended as a source of information to schools, governmental and private institutions, oil companies, and potential investors.