Abstract:

The variation of sorting,grain size and clay content is controlled by hy-drodynamic conditions.Each environment follows its own special law in hy-drodynamic properties and evolution.They may control sand distribution,sequence and log shape,with the last one reflecting the first two macro-scopic sedimentary characters(in this paper,the log refers mainly to SPcurve).Consequently,the combinations of log shapes in various environments are different.Synthesizing the characteristics of log such as amplitude,sha-pe,upper and lower contact,smooth or serrated degree,combination of logshape,and combining them with other geologic logging,we can reach a cor-rect conclusion on sedimentary environment.In eastern China,Tertiary faulted lake basins contain many kinds of en-vironments such as alluvial fans,braided and meandering streams,deltas,littoral beaches and bars,subaqueous alluvial fans,sebaqueous channels ofdensity current and turbidity current(deep Water).This paper summarizesthe characters of logs for the environments mentioned above,including thoseof single serration and combinations of log shapes reflecting the sequenceand their relations with geologic background.In the stage of exploration,a comprehensive interpretation of the charactersof these logs is helpful to geologists in explaining sedimentary environmentsand predicting distribution of sandbodies.So it is an useful method.