Hydrocarbon Migration Pathways And Petroleum Accumulation Models Of Typical Tectonic Units In Bozhong Area

Since Paleogene, strong tectonic movement resulted in the formation of multiple hydrocarbon-generating depressions, multiple hydrocarbon source rocks and multiple hydrocarbon accumulation assemblages in the Bozhong depression. This kind of complex geological condition determines that study on hydrocarbon accumulation dynamics becomes the key factor influencing hydrocarbon exploration effect. Study on hydrocarbon migration pathway and hydrocarbon accumulation model are the base of hydrocarbon accumulation dynamics. Supported by the National Key Natural Science Foundation of China and guiding with advanced theories and methods, this study analyzed hydrocarbon migration pathways and fluid flow and summarized hydrocarbon accumulation models in the different scale based on the research of regional geological background and typical petroliferous structure. The main results in this dissertation are as follows:1. Analysis on organic geochemistry of the Bozhong depression indicate that there are three sets of mature hydrocarbon source rocks including mudstones in the 3rd member of the Shahejie Formation, the 1st member of the Shahejie Formation and the lower member of the Dongying Formation, respectively. Sedimentary environment and climate determine that abundances and types of organic matters in various hydrocarbon source rocks are different. Compared with other two sets of hydrocarbon source rocks, those in the 3rd member of the Shahejie Formation not only have broader distribution and larger depositional thickness, but also have plentiful II A-type and II B-type kerogen, so are the best of the three sets of mature hydrocarbon source rocks. Compositions of biomarkers are different in various hydrocarbon source rocks. They can be effectively distinguished according to values of their gammacerane/C₃₀aβ-sterane and 4-methylsterane/C29 regular sterane. Crude oil displays multiple types and complex geochemical characteristics, especial. Especially, crude oil in Neogene has suffered serious biodegradation, and many kinds of geochemical parameters have largely changed. Moreover, Moreover, known oil reservoirs are situated at uplifts among these depressions, benefit from multiple sets source rocks in different depressions. Therefore, we should analyze concretely for various problems.2. Measured formation temperature data show that Present formation temperature has a...