Advances in hydrocarbon generation theory (I): Generation and evolution model for immature oils and hydrocarbon

The wide existence of immature oils throughout the world, especially in China, broke through the hydrocarbon generation theory of kerogen thermal degradation. Studies have shown that soluble and insoluble organic matter are organically connected in the sedimentary rock, both contributing to hydrocarbon generation. In the diagenesis, kerogen cannot produce oils, so immature oils derive directly from the degradation of the soluble lipids. Hydrocarbon generation process by kerogen thermal degradation takes place mainly in the early catagenesis (Ro=0.5–1.2%), and the oils generated are normal. In the late catagenesis, hydrocarbon generation comes into wet gas stage (Ro=1.2–2.0%), with pyrobitumen and oils cracking into high mature light oils and wet gases, respectively. In this paper, the author presented a novel general model of hydrocarbon generation and evolution with soluble and insoluble organic matter both contributing to hydrocarbon generation.