Sequence characteristics of rifting basin of Xujiaweizi in Songliao Basin

The applications of the principle and method of sequence of rifting basin is being researched by many workers. Especially the research of sequence of Songliao Basin in China where the continental oil and gas dominate in energy resources draws more and more attention from geologists. Some schools are formed for theory of sequence,such as tectonic theory, climate theory and comprehensive theory. This paper discusses relationship between sequence types and basin types, and then the oil and gas promising and sequence of rifting basin,and analyzes strata of Late Jurasic and Early Cretaceous period of rifting basin, i.e.Huoshiling Formation, Shahezi Formation and Yingcheng Formation.According to analysis of sequence of these strata,the changes of accommodation space and its filing process were investigated,and then divided the ultra sequence.The relationship between sedimentation and volcanism was investigated.From the concept of accommodation space,volcanic rocks were put into the frame of sequence,and the system of hydrocarbon-reservoir-cover controlled by sequence and the oil and gas exploration potential were evaluted.