番禺隆起新近系层序、沉积演化与地层圈闭

综合分析钻井、地震等资料,将区内新近系划分为14个三级层序,每个层序又可以海泛面为界细分为3～5个四级层序或体系域.层序界面和水进面与浮游有孔虫的丰度和分异度变化有密切关系.结合钻井约束的地震沉积学分析,可识别出低位域(辫状河)三角洲、河流三角洲、浅海陆棚等沉积体系.地层属性分析揭示了三角洲前缘沉积在平面上特有的环状结构.以四级层序为地层单元的沉积相平面编图可很好地反映不同体系域的沉积相演化.区内的层序结构和沉积相带演化主要受到海平面变化的控制.区内存在5种潜在的岩性地层或构造-地层圈闭,由断裂坡折带控制的低位域三角洲砂体已由勘探证实可形成重要的构造-地层油气藏.

Sequence architecture, sedimentary evolution and stratigraphic traps of the Neogene in Panyu Uplift

According to the analysis of drilling data and seismic data,the Neogene in Panyu Uplift can be divided into 14 third-order sequences,and each third-order sequence can be divided into 3~5 fourth-order sequences or system tracts.There is close relationship between the sequence interface and transgressive surface and the pelagic foraminifera abundance and diversity.According to drilling constrained seismic sedimentological analysis,lowstand(braided river)delta,river delta and neritic shelf sedimentary systems are identified.Stratigraphic attribute analysis shows the unique ring structure of delta front deposits on plane.The sedimentary facies plane graph in which a fourth-order sequence is as a stratigraphic unit can well reflect the sedimentary facies evolution of different system tracts.The sequence architecture and sedimentary facies evolution in the studied area are controlled mainly by sea-level change.There are 5 lithologic--stratigraphic or structural--stratigraphic traps in the area,and exploration practice proves that the lowstand delta sandbody controlled by faulted slope break belt can form important structural-stratigraphic reservoirs.