Shahejie formation of Paleogene is the most important source rock in Huimin sag which is divided into sub-sags of l,innan, Zizheng, Yangxin, Lizezheng.

• 古近系沙河衡组是惠民凹陷最重要的生油层系，该凹陷主要由临南、滋镇、阳信、里则镇等次级洼陷组成。