Characteristics of hydrocarbon source rocks of No.3 buried-hill region in Nanpu Sag

摘要

Based on the data of 44 samples of hydrocarbon source rocks in Nanpu No.3 buried-hill region,the kerogen type is judged through the pyrolysis and microscopic identification. At the same time,organic matter maturity and hydrocarbon generation threshold are studied by using vitrinite reflectance,pyrolysis yield and hy-drocarbon abundance. Meanwhile the hydrocarbon expulsion threshold is calculated. And the characteristics of organic hydrocarbon generation and expulsion are preliminarily revealed and evaluated. The result shows that the No.3 buried-hill region has abundant hydrocarbon source rocks with high content of organic carbon. And the primary types of kerogen areⅡ1 andⅡ2. The hydrocarbon source rocks which passed biochemistry,thermolysis and thermal cracking have developed into the mature-postmature phase of different extents. And plenty of oil and gas were expelled out. It is believed the depth of oil-generating window is 3 600 m and the depth of hydro-carbon-expulsion threshold is 4 100 m. The comprehensive analysis indicates that Nanpu No.3 burried-hill re-gion has a certain condition to generate hydrocarbon which is very promising in oil exploration and thus can be-come an important exploration and development target next.