Abstract:

Lower Yangtze area is one of the prior marine blocks of petroleum exploration in South China. Aiming at marine petroleum exploration of Mesozoic and Paleozoic, the strategy of the secondary hydrocarbon generation and later formation of petroleum pool was brought forward for petroleum exploration and planning in the study area. Based on thermal history reconstruction, the thermal maturation of the marine source rocks at different geological time is evaluated. In addition, using secondary hydrocarbon generation model based on experiments, the secondary hydrocarbon generation intensity of the four sets of marine source rock is evaluated. The thermal history reconstruction reveals that there are obvious differences among Subei, Sunan and Wannan areas. The study of secondary hydrocarbon generation shows that the Upper Paleozoic and Triassic source rocks have excellent secondary hydrocarbon generation potential. Silurian source rock possesses some secondary hydrocarbon generation. Cambrian source rock, however, nearly cannot provide any secondary hydrocarbon generation. Overall, there are no advantages of secondary hydrocarbon generation in the southern areas of Jiangsu and Anhui. The intensity of secondary hydrocarbon generation in north Jiangsu basin is much stronger than that in the southern areas of Jiangsu and Anhui.

Key words:  Lower Yangtze area, heat flow history, history of maturity, secondary hydrocarbon generation