Source Rocks of the Fuyu-Yang Dachengzi Oil-layer in the Chaoyanggou Oilfield, Songliao Basin

Abstract

Based on the biomarks parameters, we contrast and analyze the relationship between the crude oil of Fuyu and Yangdachengzi oil beds in Chaoyanggou oilfield and the mudstone source rocks of the 1st Member of Qingshangkou formation in Sanzhao depression. There are two source rocks of crude oil in Fuyu oil bed of Chaoyanggou oilfield. They are the mudstone source rocks of the 1st Member of Qingshangkou formation in Sanzhao depression and in Chaoyanggou oilfield, and the contribution of the two source rocks to Fuyu oil bed are nearly the same. The crude oil of Yangdachengzi oil bed in Chaoyanggou oilfield has close relationship to the mudstone source rocks of the 1st Member of Qingshangkou formation in Sanzhao depression, but the relationship with the mudstone source rocks of the 1st Member of Qingshangkou formation in Chaoyanggou oilfield is not obvious. It conforms to the facts that the lower overpressure of mudstone source rocks in Chaoyanggou oilfield makes the thickness of the oil and gas downward shallowed and the quantity of oil into Yangdachengzi oil bed decreased.