Great quantities of oils were discovered recently in both the foreshore and onshore of the Nanpu Depression, Bohai Bay Basin. Totally 67 oil and oil sand samples were collected to perform detail conventional geochemical analysis to unravel differential characteristics and classify genetic types for the oils. Four groups of the oils in the depression are recognized, including: 1 ) onshore oils produced from Es3 interval, characterized by high abundance of 4-methyl steranes but low level of oleanane and low methylphenanthrene indices; 2) onshore oils produced from Es1 to Ed and Ng to Nm; 3) offshore oils from Ed interval, which are differentiated from onshore oils with relatively high ratios of gammacerane to C3O hopane and steranes to hopanes; 4) oils from Ordovician burial hill, which have apparent low contents of steranes and terpanes but high content of pregnane, tricyclic terpane and diasteranes, indicate relatively high thermal evolution of the oils.
