New Approach To Hydrocarbon Migration In The Polish Carpathians Based On Outcrops Analyses

Abstract

Abstract The research was carried out in different tectonic units of the Polish Carpathians. Three stages of migration were indentified with the use of fluidal inclusions in cements analyses and bitumen traces in the pore space. The main migration paths of hydrocarbons are usually mélange tectonic zones revealing signs of diversified mineralization. These out-of-sequence thrusts may demonstrate the connection with the Carpathian basement. Location of hydrocarbons reservoirs along mélange and tectonic active zones, which form the flower structures, suggests the possibility of migration of hydrocarbons from the very deep zones subsidented within the Central Carpathian Depression (CCD) graben. Hydrocarbons generated at great depths migrates along mélange and active tectonic zones. These flower structure, consisting of network of fractures, in which crucial role in hydrocarbons migration plays the most active tectonic zone (so called master fault) plays a main role in hydrocarbons accumulation e.g. CCD margin zone is an essential element for the process of charging these flower structures with hydrocarbons. Mineralogical, petrographical and geochemical (bitumen extracts, biomarkers) analyses were performed on sediments trapped in mélange zones. Completed studies have shown diversified mineralization processes and bitumen type along the main zone of the tectonic mélange. This is related to the depth of mélange zone rooting and fluid migration from the Carpathian basement rocks. Determination of hydrocarbons generation, its nature and the origin of crude oil trapped in mélange zones have a great impact on new directions in oil exploration in the CCD area.