Oil source correlation is one of the important methods to trace new oil layers and guide exploration. Based on analysis of geochemical behaviors of oil produced from Wengu 2well

correlation of crude oil and potential source rocks has been made through comparing carbon isotopes and biomarkers in combination with the regional geologic setting.As for the crude oil in Wengu 2well

hydrocarbon content is high

while nonhydrocarbons + asphaltenes content is low in its group components; the δ

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C in the components and whole hydrocarbon is light;the main peak's carbon is nC 17; and gammacerane and oleanane are abundant. Oil-source correlation indicates that the Wengu 2well buried hill reservoir belongs to young source rock and old reservoir rock type

and the Paleogene mudstone is the main source rock.The crude oil and the extract from Paleogene dark-colored mudstone have very similar δ

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C value and distribution

and both of them have high gammacerane and oleanane contents. The extract from coal-measure source rock and simulated oil have large δ

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C value

low gammacerane content and no oleanane

significantly different from the crude oil in Wengu 2well.