The exploration and utilization of petroleum are potential hazards to the environment. Successful determination of petroleum contamination in ground relies on accurate definition of the type, source and quantity of contaminant. For this purpose the Rock-Eval® pyrolysis was applied, which is a rapid quantitative (Bulk Rock method) and qualitative (fractional composition using Multi-Heating Rates method) technique. Results of Rock-Eval analysis of 13 samples of concrete and 2 samples of gravel taken from the different sites of the petrol station indicate the highest concentration of light hydrocarbons (gasoline and naphtha fractions), up to over 5% wt. in the direct proximity of petrol pumps. Similarly high contamination (almost 4%wt.), was found near fuel tanks. Here the highest contribution has lubricating oil fraction and the tankers providing fuels are probably the source of this pollution. In the gravel collected in the vicinity of the fuel tanks high concentration (over 5 wt.%) of non-pyrolyzable carbon (soot) was recorded, the source of which are probably diesel engines of fuel tankers supplying fuel.
Paweł Kosakowski, Dariusz Więcław, Adam Kowalski and Yuriy Koltun
Assessment of hydrocarbon potential of Jurassic and Cretaceous source rocks in the Tarnogród-Stryi area (SE Poland and W Ukraine)
The Jurassic/Cretaceous stratigraphic complex forming a part of the sedimentary cover of both the eastern Małopolska Block and the adjacent Łysogóry-Radom Block in the Polish part as well as the Rava Rus'ka and the Kokhanivka Zones in the Ukrainian part of the basement of the Carpathian Foredeep were studied with geochemical methods in order to evaluate the possibility of hydrocarbon generation. In the Polish part of the study area, the Mesozoic strata were characterized on the basis of the analytical results of 121 core samples derived from 11 wells. The samples originated mostly from the Middle Jurassic and partly from the Lower/Upper Cretaceous strata. In the Ukrainian part of the study area the Mesozoic sequence was characterized by 348 core samples collected from 26 wells. The obtained geochemical results indicate that in both the south-eastern part of Poland and the western part of Ukraine the studied Jurassic/Cretaceous sedimentary complex reveals generally low hydrocarbon source-rock potential. The most favourable geochemical parameters: TOC up to 26 wt. % and genetic potential up to 39 mg/g of rock, were found in the Middle Jurassic strata. However, these high values are contradicted by the low hydrocarbon index (HI), usually below 100 mg HC/g TOC. Organic matter from the Middle Jurassic strata is of mixed type, dominated by gas-prone, Type III kerogen. In the Polish part of the study area, organic matter dispersed in these strata is generally immature (Tmax below 435 °C) whereas in the Ukrainian part maturity is sufficient for hydrocarbon generation.