南堡凹陷东营组层序地层格架及沉积相预测

黄骅坳陷南堡凹陷属走滑伸展型断陷，古近系东营组主要发育冲积扇-扇三角洲-湖相沉积体系。为了查明南堡凹陷油气分布规律及勘探前景，利用高分辨率层序地层学方法，结合岩心、测井和地震资料分析，识别南堡凹陷东营组各级层序界面和相序，建立等时地层层序格架和演化模式，综合预测层序地层格架下的沉积相和油气分布。研究认为：层序界面、最大湖泛面、层序格架下的沉积相分布和构造背景是有利砂体分布和油气富集的主控因素，东营组油气分布具有纵向相对集中和平面分带的特点，表现为油气主要富集于最大湖泛面之下的东三上亚段地层中，且多分布于凹陷第二走滑断阶带。图7参16

Sequence stratigraphic framework and sedimentary facies prediction in Dongying Formation of Nanpu Sag

The Nanpu Sag is a downfaulted lacustrine basin with strike-slip faulting.The Palaeogene Dongying Formation is dominated by the depositional system of alluvial fan facies,fan delta facies(braided delta facies) and lacustrine facies.With the high resolution sequence stratigraphy and the correlation analysis of cores,logs and seismic data,different orders of sequence boundaries and facies sequence are identified and the isochronous stratigraphic framework and the depositional evolutional model of Dongying Formation are built and used to predict the distribution of reservoirs.The study shows that stratigraphic sequence boundary,maximum flood surface,sedimentary facies and structural settings are the dominant factors controlling the distribution of favorable sand bodies and oil reservoirs in the Dongying Formation.The distribution of oil reservoirs is dominated by such characteristics as relatively vertical concentration and area zonation.A lot of hydrocarbon reservoirs are concentrated in Ed_1 that underlies the maximum flood surface vertically.Those discovered reservoirs are typically distributed in the second strike-slip fault zone in Nanpu Sag.