Chengbei oilfield located in Bohai sea is a viscous field with a development history more than twenty years,and its main developed pays are in Paleogene Dongying formation and Neogene Guantao formation.

• 埕北油田位于渤海海域,是一个已有20多年开发历史的稠油油田,其主要开发层系为古近系东营组上段和新近系馆陶组。