Secondary hydrocarbon generation only occurred in the Bohai Bay Basin,while there only existed one in the Ordos Basin,NW China,due to high evolution of organic matter.

• 二者的上古生界储集层都属于低孔低渗类型,盖层对生成的油气都能起到很好的封盖作用,认为二者成藏模式十分相似。