This paper evaluated the coal measure source rocks of the Middle and Lower Jurassic Xishanyao Formation

Sangonghe Formation and Badaowan Formationin of Bohu depression in Yanqi Basin by using many organic geochemical methods.The results showed that the source rocks are higher in abundance of organic matter.The Lower Jurassic Badaowan Formation is good source rock

while the Xishanyao and Sangonghe formations are moderate source rock.The types of organic matter are dominated by kerogen Ⅲ with few kerogen Ⅱ

2

. Most of the organic matters are within oil window.The organic matters in the Xishanyao Formation are low mature;that in the Sangonghe Formation are partly mature

and that in the Badaowan Formation are mature and in peak oil-generation stage.By comparison of the hydrocarbon generation capacity of the three subsags and the three Formations

the Badaowan Formation is identified as the main source rocks in Yanqi basin.In addition

similar with the source rocks in the Badaowan Formation

the source rocks in the Sangonghe Formation of Qilipu subsag also have high TOC

good organic matter type

suitable thermal maturity

thus have great potential for hydrocarbon generation.According to exploration experiences in recent years

the area along both sides of the structural highs and slope zones of Qilipu subsag is favorable exploration play.