High-resolution Sequence Stratigraphy of Paleogene in Dongying Depression
LI Yang CAI Jing-gong LIU Jian-ming (Shengli Oillfield Limited Corporation,Dongying,Shandong 257000)
Based on the analyses of structural sequences and base level, high-resolution stratigraphic framework is established and suggested a tectonic control on sequences formation in Dongying depression. The sequences developed in faulted lake-basin are composed of lomstand(LST),lake expansion(EST) and highstand system tracts(HST).They can be further grouped into three sequence styles, growth -fault style,structuracl-break style and ramp style, in the light of the features of lomstand system tracts and spatial configurations of depositional systems. The former is dominated by lowstand system tracts, the second is composed of complete three component system tracts(LST, EST and HST),which is similar to the pattern developed in marine passive continental margin, the last one is dominated by shallow-lake depositional packages. The structural break provides substantial accommodation space for the development of lowstand fan, which include lowstand deltas, turbiditic fans and fan-deltas. They are the major exploration targets for subtle hydrocarbon reservoir, which are of good commerical siginificances proven by drilling. This study shows a prosperous application of sequence stratigraphy into the esploration in continental basins.