Abstract: Since more than 60 year exploration and development, the Bohai oilfield has now been a super large offshore oilfield in China. This paper reviews the exploration progresses of Bohai oilfield since the 13th Five Year Plan (2016-2020), and clearly points out the key exploration fields and research directions in future based on the analysis of regional accumulation conditions. The Bohai Sea area mainly develops three sets of main source strata, i.e., Member 3 of Shahejie Formation, Member 1 of Shahejie Formation, and Member 3 of Dongying Formation. Vertically, the Cenozoic clastic reservoirs and buried-hill fractured reservoirs constitute the main productive series. Based on recognition of the special geological conditions of Bohai Sea, such as "intense Mesozoic destruction, rapid Paleogene transformation, and thick Neogene sedimentation", the paper establishes and developes multiple new petroleum geological understandings of the three major exploration fields in Bohai oilfield, including "complex metamorphic buried-hills", "Paleogene structure-lithology", and "large-scale Neogene lithology", which has achieved significant discoveries of five oilfields of 100 million tons in five years. Through the systematic analysis of source rocks, reservoir cap association, and other regional accumulation conditions in the basin, it is specified that the main potential areas for future conventional exploration fields are the buried-hill field including Liaonan belt, Liaobei belt and circum-Bozhong sag, the Palaeogene field including Liaozhong-Liaoxibei subsag belt, Shinan steep-slope belt, Bozhong southwest area and north steep-slope belt of Huanghekou sag, and the shallow Neogene field in circum-Bozhong sag. For unconventional oil-gas field, shale oil in Laizhouwan sag should be prioritized. The crude oil and natural gas in the above-mentioned conventional hydrocarbon traps are approximately estimated to be 8.7×10⁸t, and 1.9×10¹²m³, respectively; the unconventional shale oil resource amounts to nearly 8.6×10⁸t in Laizhouwan sag. It is pointed out that the future oil-gas exploration in Bohai Sea needs to realize four shifts, i.e., the shift of buried hill exploration from traditional buried-hills to hidden buried-hills, the shift of Paleogene exploration from medium-deep to deep and ultra-deep strata, the shift of shallow lithology exploration from salients and slopes to sags, and the shift of exploration fields from conventional to both conventional and unconventional oil-gas. The research results can contribute to the advancement of oil-gas geological theory and technology in complex continental downfaulted basins, providing theoretical understanding and support for the stable and sustainable development of Bohai oilfield.

Key words: exploration progress, new fields, new types, resource potential, Bohai Sea

摘要： 渤海油田历经60余年勘探开发，目前已建成中国海上超大油田。综述渤海油田"十三五"（2016—2020年）规划以来的勘探进展，在剖析区域成藏条件的基础上，指明了未来的重点勘探领域与攻关方向。渤海海域主要发育沙河街组三段、沙河街组一段与东营组三段3套主力烃源岩；垂向上，潜山裂缝型与新生界碎屑岩孔隙型2类储集体构成了主要的产油层系。基于对渤海海域"中生代强破坏、古近纪快转换、新近纪厚沉积"等特殊地质条件的再认识，渤海油田在"复杂变质岩潜山"、"古近系构造-岩性"与"新近系大规模岩性"3大勘探领域建立并发展了多项油气地质新认识，实现了5年5个亿吨级油田的重大发现。通过系统分析盆地烃源岩、储-盖组合等区域成藏条件，明确了潜山领域的辽北潜山带、辽南潜山带和环渤中凹陷隐蔽型潜山，古近系领域的辽中—辽西北部洼陷带、石南陡坡带、渤中凹陷西南环地区和黄河口凹陷北部陡坡带，以及浅层新近系领域的环渤中凹陷是未来常规领域的主要潜力区，非常规油气领域应优选莱州湾凹陷页岩油进行重点探索。在上述领域的常规油气圈闭中，原油资源量约为8.7×10⁸t，天然气资源量约为1.9×10¹²m³；莱州湾凹陷的非常规页岩油资源量为8.6×10⁸t。渤海海域未来油气勘探需要实现4个转移，即潜山勘探由传统的显性潜山向隐蔽型潜山转移、古近系勘探由中—深层向深层—超深层转移、浅层岩性勘探由凸起和斜坡区向凹陷区转移、勘探领域由常规油气向"常规、非常规并重"转移。研究成果有助于推动复杂陆相断陷盆地油气地质理论的技术进步，为渤海油田的稳定可持续发展提供理论认识支撑。

关键词: 勘探进展, 新领域, 新类型, 资源潜力, 渤海海域