Origin, migration and secondary processes of oil and natural gas in the western part of the Polish Outer Carpathians: geochemical and geological approach

Abstract The origin, migration pathways, as well the influence of secondary processes oil and natural gas accumulated in lower Cretaceous to Miocene strata western part Polish Outer Carpathians (between Kraków Pilzno towns) based on results organic geochemical analyses are investigated this paper. Oil thermogenic hydrocarbon gases were generated mainly from type II kerogen, III kerogen mixed various proportions. These kerogens occur Oligocene Menilite beds Silesian Dukla nappes. Oils early late “oil window”. Secondary cracking was recorded oils nappe, other including biodegradation, water washing evaporative fractionation also developed a extent many oils. most biodegraded seep S-Li, extensive is observed S-Sa/1. significantly selected deepest parts multi-horizontal Biecz field. Hydrocarbon originated during both microbial matter transformation. Natural has not been subjected biodegradation processes. Carbon dioxide derived decomposition together with gases.