渤海湾盆地辽东-渤东凸起构造带地质结构与形成演化

    Geological architecture and tectonic evolution of Liaodong-Bodong Uplift tectonic belt, Bohai Bay Basin

    • 摘要: 为了明确渤海湾盆地辽东-渤东凸起构造带的形成演化过程与油气的关系,结合研究区最新三维地震数据,详细分析了辽东-渤东凸起构造带的地质结构特征和隆升时间,对比了构造变形特征,确定了隆升时间的差异性,在此基础上建立了辽东-渤东凸起构造带的形成演化模式。研究认为,渤东低凸起受控于伸展断层,辽东凸起受控于早期伸展断层和晚期走滑断层,构造带内除辽东断层以外,各主干断层均在孔店组—沙四段沉积期开始活动,峰值期出现在沙三段和东营组沉积期,馆陶组沉积后断层活动变弱。辽东-渤东凸起构造带从南向北逐渐抬升:渤东低凸起在沙四段沉积末期抬升,辽东凸起南段在沙三段沉积末期抬升,辽东凸起北段在东三段沉积末期抬升。构造演化分为孔店组-沙四段沉积期、沙三段沉积期、沙一二段沉积期、东三段沉积期、东营组沉积末期和现今等6个阶段。构造演化与油气运聚成藏密切相关,辽东-渤东凸起构造带的形成时间早于周缘生烃凹陷主要生、排烃期,有利于油气在凸起带附近聚集。渤东低凸起由伸展断层控制,油气主要在凸起区聚集成藏;辽东凸起由伸展断层与走滑断层共同控制,油气主要在斜坡区聚集成藏。

       

      Abstract: To clarify the formation and evolution process of Liaodong-Bodong Uplift tectonic belt and its relationship with oil and gas in Bohai Bay Basin, by combining the latest three-dimensional seismic data in the study area, the tectonic characteristics and the uplift time of the tectonic belt was analyzed in detail, the structural deformation characteristics were compared, and the difference in the uplift time was determined, based on which the formation type and evolution model of the tectonic belt was established. It is considered that the Bodong Low Uplift in the tectonic belt is mainly controlled by the extensional fault, while the Liaodong Uplift is mainly controlled by the early extensional fault and the late strike slip fault. Except for the Liaodong Fault, all the main faults in the tectonic belt started to move in the sedimentary period of the Kongdian Formation and the fourth member of Shahejie Formation, or the Sha-4 Member for short, and the peak period is from the sedimentary period of Sha-3 Member and Dongying Formation, and the fault activity was relatively weak after the deposition of Guantao Formation. The uplift time of the tectonic belt rose gradually from south to north: Bodong Low Uplift rose at the end of the deposition of the Sha-4 Member, the southern section of Liaodong Uplift rose at the end of the deposition of the Sha-3 Member, and the northern section of Liaodong Uplift rose at the end of the deposition of the third member of Dongying Formation (or Dong-3 Member in short). The tectonic evolution could be divided into six stages: sedimentary period the Kongdian Formation to Sha-4 Member , sedimentary period of the Sha-3 Member, sedimentary period of the Sha 1 and 2 Members, sedimentary period of the Dong 3 Member, the end of the Dongying Formation, and the present. The tectonic evolution is closely related to the migration and accumulation of oil and gas. The formation time of the tectonic belt before that of the main hydrocarbon generation and expulsion period of the peripheral hydrocarbon generation depression, which is conducive to the accumulation of oil and gas near the tectonic belt. It was easy for oil and gas to accumulate in the bulge area of Bodong low uplift controlled by extensional fault, and for oil and gas to accumulate in the slope area controlled by strike slip fault.

       

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