渤海湾盆地东营凹陷现河矿区古近系断裂体系及形成演化

Paleogene fault system in the Xianhe mining area,Dongying Sag,Bohai Bay Basin and its evolution

受双重动力背景控制,渤海湾盆地东营凹陷现河矿区古近系伸展与走滑作用叠加明显,明确断裂体系叠加关系对油气勘探意义重大。文章运用高精度地震资料及钻井资料,通过井震结合解释、构造样式识别、断裂活动性定量表征及平衡剖面恢复等技术手段,从断裂类型与组合样式、断裂叠加关系、断裂活动及演化、区域动力学背景等方面开展了深入研究。结果表明:现河矿区古近系发育伸展与伸展-走滑两套断裂体系,伸展-走滑断裂基于先期伸展断裂叠加走滑作用形成。古近系主干断裂存在沙三中期和东营早期两次活动高峰,受控于伸展-走滑应力叠合作用,现河矿区古近系共经历初始伸展阶段(Ek—Es_(4))、强伸展阶段(Es_(3)^(下)—Es_(2)^(下))、走滑-弱伸展阶段(Es_(2)^(上)—Es_(1))、再活化伸展阶段(Ed)和定型保留阶段(N-Q)5个主要的断裂演化阶段。

Controlled by the dual dynamic background,the superposition of Paleogene extension and strike slip is obvious in the Xianhe mining area,Dongying sag,Bohai Bay Basin.It is of great significance to clarify the superposition relationship of fault system for oil and gas exploration.In this paper,by using high-precision seismic data and drilling data,and by means of integrated interpretation of well-log and seismic data,structural style identification,quantitative characterization of faulting and balanced profile recovery,we carried out in-depth studies on the types and combination styles of faults,superposition relationship of faults,faulting and evolution,and regional dynamic background.The results reveal both extensional fault system and extension-strike-slip fault system of the Paleogene in Xianhe mining area,and extension-strike-slip fault is formed by the superposition of the earlier extensional faults.Regional faulting reaches two peak in the Paleogene,and one is in the middle of Member 3 of the Shahejie Formation and the other is in the early of Dongying Formation.Under the superposition of extensional and strike-slip stress,the faults in the Xianhe mining area experienced five major evolution stages:initial extensional stage(Ek-Es_(4)),intensely extensional stage(Es_(3)^(x)-Es_(2)^(x)),strike-slip stage and weak extensional stageEs_(2)^(s)-Es_(1),reactivation and extensional stage(Ed),and stabilization stage(N-Q).