Abstract:

Southern Songliao basin can be divided into 4 types of litho-trap and composite trap namely,channel sandbody,progradational leafy sandbody,fault-litho-trap and structural-litho-trap.Channel sandbody in seismic profile displays strong amplitude,preclination of low frequency and down concave reflection.If river bank is steep,the river bed can be defined by termination point of horizontal reflection,point sandbar showing slightly convex while channel displaying the characteristic of concave.Progradational reflection configuration of the progradational leafy body shows gentle downlap or toplap.Deltaic sheet sandbody can be defined by warped part of progradatioal bed or warped part of toplap pinch out bed.Branch channel sandbody can be identified by the abnormality of structure and waveform through amplitude.Changes for amplitude and waveform in strata series of deltaic progradation are closely connected with the sandbody.Daqingzijing area and southeasthern source area are believed to be favorable prospecting oil and gas reservoirs while Qianan-Gudian area is considered to be relatively favorable prospecting oil and gas reservoir.

Key words: Songliao basin, sequence stratigraphy, subtle trap, channel