Abstract:

The theory of prolific depression is essentially to let us have an idea of "depression fully filled with oil and gas" namely,the depression with rich source rocks,high resource abundances,enriched-oil and gas,and to search for not only reservoirs in positive structural zone,but also more important to search for reservoirs in negative structural zone as well,and to search for different subtle reservoirs in particular. There are various subtle reservoirs such as lithologic reservoir,stratigraphic reservoir,especially as well as volcanic rock reservoir and buried hill reservoir etc.,the reserves of which making up almost 40% of the total proved reserves in the study area.The prolific depression in Dongyang,Zhanhua,Western and Eastern Liaoning,Damintun,Raoyang,Qikou and Banqiao etc.have been discovered with high resource abundances,and large well- developed subtle reservoirs with great potential for the exploration of oil and gas. Deep buried hill,turbidite body in the sag zone,sand body in the steep gradient zone,the third member from Shahejie- Formation and the Mesozic volcanic rock,water encroachment overlapping delta sand body in the gentle slope zone as well as complex subtle blocks etc.are believed to be major projecting areas for the exploration of oil and gas in prolific subtle reservoirs.

Key words: prolific depression, subtle reservoir, exploration potential, exploration direction