Thermal History Modeling And Analysis Of Hydrocarbons Migration In Bai Yun Depression And Pan Yu Low Uplift, Pearl River Mouth Basin, South China Sea

Pearl River Mouth Basin (PRMB) is a typical passive margin basin located on the northern shelf of the South China Sea (SCS); it contains three (3) large depressions (Zhu-1, Zhu-2 and Zhu-3) interconnected by half-graben or sub-units separated by intervening ridges. These sub-units can further be subdivided into several smaller sub-units such as Pan Yu Low uplift and Bai Yun depression which are located within Zhu-2 depression.Pearl River Mouth Basin formed Late Cretaceous-Early Paleogene in response to the opening of the South China Sea, which followed by a Middle Oligocene erosion and a Late Oligocene to Holocene down warp phase. The basement complex is mostly Mesozoic igneous and metamorphic rocks. Most of the Tertiary sequences in the basin are terrigeneous clastics.Relatively little information has been available on the hydrocarbon maturation and expulsion histories of the potential source rocks in Pan Yu Low uplift and Bai Yun depression, and whether these factors directly impact on the prospectivity of the region. Thermal history modeling is very important for understanding of the timing of hydrocarbon generation, expulsion and "how and where" the potentially generated hydrocarbons migrated and are being trapped.The dissertation provides burial and thermal histories at the following wells: LH21-1-1, PY24-1-1, PY28-2-1, PY30-1-1 and PY33-1-1 by utilizing an integrated stratigraphic, sedimentological and geochemical approach in the Petromod 7.1 (1-D, which makes use of physical, thermal and geochemical data) software package released to China University of Geosciences, 2005.Satisfactory profiles matching results were constructed from well data using multiple maturity parameters. Modeling shows that the maximum paleotemperatures were attained in the source rocks (Zhu Hai, En Ping and Wen Chang Formations respectively from top to bottom) units by burial in the northern part of Bai Yun depression and at the margins of Pan Yu Low uplift during Late Oligocene. Our study indicates that R₀ and T_max data are reliable and can be used to evaluate thermal maturity unlike in previous studies in the same area.High maturity values are observed in the Bai Yun depression, which indicated high palaeo temperatures, presumably during the maximum burial phase in the Late Oligocene-Early Miocene. In contrast, maturity data in the Pan Yu Low uplift, suggest that heat flows of only...