渤海海域砂砾岩体沉积响应进展及热点

Development and Hotspots of Sedimentary Response of Glutenite in the Offshore Bohai Bay Basin

随着全球能源需求日益增长,砂砾岩油气藏研究逐步深入,新疆准噶尔盆地玛湖大型砾岩油藏与渤海海域渤中19-6大型整装凝析气田获重大发现,使得砂砾岩体成为油气勘探新领域.当前,砂砾岩体沉积响应研究集中于陡坡背景或造山带背景,重点解析冲积扇、扇三角洲、近岸水下扇与湖底扇体系的结构样式、控制因素、沉积模式及其差异性,但机制成因方面存在多解性.渤海海域内砂砾岩体主要发育于始新世陡坡背景与中新世初期缓坡背景,其中始新世砂砾岩沿断裂陡坡带呈裙带状近源堆积,热点集中于其结构识别及期次刻画,以期准确预测地下砂砾岩体储层时空分布;而中新世初期转换界面处砂砾岩广泛分布且伴随岩浆活动,难点在于明确砂砾岩体沉积学信息、年代学信息同重大板块构造变革间响应关系,厘定大面积砂砾岩体分布的成因机制及发育模式.砂砾岩体沉积响应的研究方向将立足于完善岩相划分标准、依据,深化其与区域构造事件关联性,定量化解析沉积充填响应过程及工业化刻画其圈闭目标,系统研究对揭示渤海海域新生代盆地形成演化有重大理论意义,同时可服务大中型砂砾岩油气田的勘探需求.

With the increasing global energy consumption and deepening glutenite oil and gas reservoirs study,glutenite reservoirs have become a new field of oil and gas exploration,especially since the significant discoveries of conglomeratic reservoirs in the Mahu area,Junggar basin of Xinjiang,and integrated condensate gas field of BZ19-6 in the offshore Bohai Bay basin.At present,the research on the sedimentary response of glutenite is concentrated on the background of steep slope or orogenic belt,focusing on the analysis of the forms,structural styles,controlling factors,depositional modes and differences of alluvial fan,fan delta,nearshore subaqueous fan and sublacustrine fan systems,but there are multiple explanations for the genetic mechanism.Glutenites in the offshore Bohai Bay basin are mainly developed in Eocene steep slope background and early Miocene gentle slope background.Among them,Eocene glutenite presents a near-source accumulation along the fault steep slope belt,and the hotspots focus on its structure identification and period characterization,so as to accurately predict the spatial and temporal distribution of underground glutenite reservoirs.However,at the transition interface of the early Miocene,a set of glutenite is widely distributed and accompanied by magmatic activities.The difficulty lies in defining the response relationship between sedimentological and chronological information of glutenite and the evolution of tectonic plates,and determining the genetic mechanism and development mode of large-scale glutenite reservoirs distribution.Sedimentary response research direction of glutenite will be based on the principles and standard of lithofacies subdivision,to deepen its relationship with regional tectonic events,analyze the infilling processes quantitatively and depict its trap target of industrialization.These results would not only offer better understanding of the formation and evolution of Cenozoic Bohai Bay basin,but also facilitate the exploration of the middle and large-scale oil and gas fields with the type of glutenite in the offshore Bohai Bay basin.