ANALYSIS ON OIL SOURCE OF LOWER PALAEOZOIC CRUDE OIL FROM KAILI AREA IN GUIZHOU PROVINCE

The geochemical characteristics of the Lower Palaeozoic crude oil from Kaili and its adjacent areas in Guizhou Province has been analyzed with emphasis in this paper based on the characteristics of the source rocks of the same areas.The results show that the stable carbon isotopic composition of the Lower Palaeozoic crude oil and oil sand is similar to that of the Lower Palaeozoic source rock extract,but obviously different from that of the Permian source rock extract,indicating that the crude oil is more closely related to the Lower Palaeozoic source rocks.While the biomarker parameters of the crude oil and the oil sand,such as the regular sterane,the tetracyclic terpane and the gammacerane/C₃₁-hopane,are more related to those of the Permian source rocks,indicating that the oil from the Lower Palaeozoic and the oil sand may be the mixture of oils generated from the Lower Palaeozoic and the Permian source rocks.The formation process of the mixture oil has also been discussed based on the structural-sedimentary evolution history and the hydrocarbon generation history of the source rocks in the study area.