Orgaofaices evolution of deep Es4 source rock in Baxian Sag, Jizhong Depression of Bohai Bay Basin and its significance, China

Abstract

The Es4 source rock is the primary source of hydrocarbon in deep reservoirs in the Baxian Sag, Jizhong Depression of Bohai Bay Basin, China, and its quantitative description is useful for understanding hydrocarbon generation and accumulation in the deep basin. The Es4 source rock contains organofacies C, D/E and F, with organofacies C having a thin thickness of less than 40 m and organofacies D/E having a thickness of 50 m and 250 m. The drilled Es4 source rock has a maximum RO of 1.27%, indicating that it is in the late oil window. The kinetic parameters for three organofacies source rock have been obtained from the simulation of gold tube pyrolysis. The result showed that organofacies C, D/E and F source rock entered into the mature level in sequence, but that at 150 °C, the organofacies C will be transformed to around 90% of their original state. For organofacies D/E and F, the hydrocarbon generation potential is still high, with condensate and wet gas dominating.

Keywords

• Baxian Sag
• Gas-prone source rock
• Hydrocarbon in deep formation
• Natural gas
• Condensate