High Precision Sequence Division and Geological Significance of Nantun Formation in Wunan Subsag

5th Annual International Workshop on Materials Science and Engineering

Li, Junhui^1

Exploration and Development Research Institute, Daqing Oilfield Company Limited, Daqing

163712, China^1

关键词: Braided river deltas;    Distribution characteristics;    Geological significance;    High-precision;    Remaining layers;    Sedimentary systems;    Sequence boundary;    Sequence stratigraphic framework;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/585/1/012083/pdf
DOI  :  10.1088/1757-899X/585/1/012083

来源: IOP

【 摘 要 】

Based on the data of core and logging, high precision sequence stratigraphic framework of Nantun Formation of Wunan subsag, Wuerxun Depression in Hailar Basin and sedimentary systems distribution characteristics which is under its control are studied. It shows that there are five types of sequence boundaries in Nantun Formation, and it can further be broken into 3 three-level and 9 four-level sequence. According to the variation of remaining layer thickness of each sequence, the change rule of deposition centers in Nantun Formation appears transferring to west gradually, and from down to up the formation distribution characteristics changes from 'medium thickness to east and west thin' to 'west thick- east thin'. During the sedimentary period, four sedimentary systems mainly develops: braided river delta, fan delta, sublacustrine fan and lake. The plane distribution of sedimentary system has the characteristics of 'east-west zoning'. The fan delta sedimentary system mainly develops in the western Wuxi slope zone, and the braided river delta mainly develops in the eastern Wudong gentle slope zone. The plane distribution characteristics of each sedimentary system in different periods have obvious inheritance.