高级检索

    北黄海东部次盆地下白垩统沉积环境及沉积充填

    Early Cretaceous sedimentary environment and filling in the Eastern Subbasin, North Yellow Sea

    • 摘要: 下白垩统是北黄海东部次盆地目前最重要的油气勘探层位,准确认识下白垩统的沉积特征,对下一步油气勘探战略选区及优化勘探部署具重要意义。依据钻测井、地震资料,利用古生物、地球化学、地球物理等手段,研究了下白垩统的沉积相类型,分析了古气候、古盐度、古水动力、古物源等沉积环境,最终探讨了三级层序地层格架内下白垩统的沉积充填及演化。结果表明,北黄海东部次盆地下白垩统发育扇三角洲-湖泊沉积体系。该时期以亚热带炎热半干旱气候为主,夹短暂温湿气候。古水体为淡水-半咸水性质,接受来自北部、东部、西南等多个方向的物源供给。早期地层分布局限,以滨浅湖亚相、扇三角洲相沉积为主;之后,湖泊水体范围扩大,发育扇三角洲平原-扇三角洲前缘-滨浅湖亚相沉积序列;中晚期地层受区域抬升作用的影响,仅残存于盆地西北部,以滨浅湖相沉积为主。

       

      Abstract: The Lower Cretaceous strata constitute the most important oil and gas exploration horizon at present in the Eastern Subbasin of the North Yellow Sea. Accurate understanding of the Lower Cretaceous sedimentary characteristics is very important for the further strategic exploration and optimization of exploration deployment. According to drilling, well logging and seismic data and by means of paleontology, geochemistry and geophysics, the sedimentary facies types in the study area were analyzed. The sedimentary environments of paleoclimate, paleo-salinity, paleo-hydrodynamic force and provenance were studied. Finally, the sedimentary filling and evolution characteristics of the Lower Cretaceous period were discussed under the third sequences stratigraphic framework. The results show that the fan deltas and lucustrine facies were developed in the Lower Cretaceous. This period was dominated by subtropical hot and semi-arid climate, characterized by shortage of warm and humid climate. The ancient water bodies were fresh and brackish. The provenance was from north, east, southwest and some other directions. The early stratigraphic distribution of Lower Crataceous was limited, and the sedimentary facies were dominated by shore shallow lake and fan delta interbedding. After that, the lake water bodies expanded, and the sedimentary sequence of fan delta plain, fan delta front and shore shallow lake developed vertically. In the middle and late stage, influenced by the regional uplift and denudation, the strata remained only in the northwestern part of the basin, and the sedimentary facies were dominated by shore shallow lake.

       

    /

    返回文章
    返回