The Jurassic oil accumulation is considered as oil derived coal because it occurred on coal bearing strata. Luacustrine mudstone and sapropel coal in the middle Permian and the low Jurassic as well as cannel boghead in the middle and upper Triassic have abundant exinoid group and saprepel group

they have highest hydrocarbon-generating potentiality in the basin

while humic coal distributed in the middle and lower Jurassic has abundant vitrinite and inertrinite which has poor liquid hydrocarbon generating potentiality. The hydrocarbon generating assemblage can be divided into two types of cannel boghead deep lake mudstone and humic coal cannel coal shallow lake mudstone in this basin. The Jurassic crude oil is rich in hopane and poor in terpane with type of " V" of sterane indicated by the biomarkers shows that the bacterial and biota in water are mainly liquid hydrocarbon producing matter. Theses features are much like those of lacustrine mudstone and cannel boghead in the Permian. With characteristics of rich in terpane

poor in light hydrocarbon and type of "reversed L Shaped" of sterane shows that the hydrocarbon generating potentiality in humic coal is very low and higher plants are mainly plants for hydrocarbon generation. The Jurassic oil accumulation is a mixed oil sourced accumulation characterized by lacustrine mudstone

cannel boghead in the Permian

Triassic and the lower Jurassic.