Sedimentary architecture and evolution of slope channel system and sequence stratigraphic framework:A case from northeast of Baiyun sag,Pearl River Mouth basin
Ma Ming;Lin Changsong;Tao Ze;Jiang Jing;School of Energy Resources,China University of Geosciences(Beijing);School of Ocean Sciences,China University of Geosciences(Beijing);China Ocean Mineral Resources Research and Development Association;
Based on 3D seismic data,combined with well logging,sea-level changes and paleontological data,the Hanjiang formation in northeast Baiyun sag of Pearl River Mouth basin is divided into 3 three order sequences SQhj1,SQhj2 and SQhj3,respectively. Identification of three order sequence intereface depends on unconformities on the margin of basin and their correlative conformities,including onlap and erosion unconformities on the margin of basin,cutting erosion channels on the slope and slope fan and bottom floor fan intereface. Four three level sequence interfaces SBhj1,SBhj2,SBhj3,SByh1,corresponding to 4 stage regression event,respectively as 15. 5,13. 8,12. 5 and 10. 5 Ma,at the same time,it also corresponds to the low content of foraminifera and calcareous nannofossils. By means of division of sedimentary units on high resolution 3D seismic profiles,we can identify basal lags,lateral progradation packages,slumps,channel axial and channel and levee system. Different channels have different combinations of sedimentary units. There are 4 types of superimposed channels in the channel complex: swing tape,vertical accretion type,restrictedly-unidirectionally migrating tape and non-restrictedly unidirectionally migrating tape. According to the difference of sea level change and geomorphic characteristics and hydrodynamic conditions,the channels of Hanjiang formation can be divided into 3 stages,and channel developed in different periods has a particular sedimentary structure and evolution process. The results of this study have reference significance for further prediction of favorable sandstone bodies.