Influences of the basin brines on extractable bitumen of Kupferschiefer from southwestern Poland

Abstract

A study of the influences of the basin brines on hydrocarbon generation of the Kupferschiefer in southwestern Poland has been carried out. The samples from the Konrad and Polkowice mines were analyzed by organic geochemical, microscopic and FTIR methods. The results indicate that organic matter of Kupferschiefer tends to decrease with the ascending, oxidizing brines. In the Konrad profile, the Kupferschiefer was strongly oxidized. The extract yields were depleted up to 50mg Ext/g Corg. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) data indicate that the depletion occurred predominantly in saturated hydrocarbon compounds. The identified n-alkanes in sample KD1 were depleted at least to 5000 μg/g Corg. The aromatic compounds show a different trend of variation. The concentrations of phenanthrene + alkylphenanthrenes (Ph-PAH) and naphthalene + alkylnaphthalenes (Na-PAH) show a decrease, whereas sulfur polyaromatic hydrocarbons (S-PAH) and oxygen polyaromatic hydrocarbons (O-PAH) show an increase under the influences of oxidizing brines. In the Polkowice profile, organic matter under the influences of oxidizing fluids shows a similar trend of variation as in the Konrad mine. Analyses of polar compounds shed light on the oxidation processes at the molecule level. The dominant products of oxidation are aliphatic acid, alcohol and ester. FTIR results indicate that the oxidation of organic matter led to a decrease in aliphatic CH3 and an increase in C-O, C=O bands.