Prospecting potential and targets of buried-hill oil and gas reservoirs in Bohai Bay Basin

The buried hills in the Bohai Bay Basin have experienced over 40 years'exploration.And based on its exploration course and rules,the buried hill exploration is divided into four stages by ten years,including scale discovery stage,downturn stage,slow discovery stage and new stage.It is indicated from deep resource study that hydrocarbon resource is abundant and buried hill exploration is based on ample resource.It is shown from current situations that buried hill exploration is unbalanced in types,exploration series of strata,depth and degrees,which provides immense prospecting potential.From the exploration practices in Archaean metamorphic rock buried hill in Xinglongtai of the Liaohe Depression and in Wumishan deep buried hill in Niudong of the Jizhong Depression,buried hill exploration will be subsequently conducted in the deeper reservoirs and those below 4 000m will be the hot spots of exploration.The principal type of buried hills varies from weathering crust to internal buried hill.Central sags and swells are the focused exploration targets of internal buried hills.And the exploration presents obvious depression replacement.Attentions are paid on the beaches in the Huanghua Depression and the Liaohe Depression and those areas with low exploration degree.In terms of exploration degree,26 buried-hill zones present higher exploration potential,including Daxing-Gu'an,Shubei-Niuxintuo,Changlu,Wangguantun-Wumaying,Yannan,Bijialing,Haiyue and so on.New discoveries will be surely realized in the exploration of buried hills.