Abstract：According to not only the lithologic-mineral characteristics but also the identification signs of land-facies sequence in seismic section and electric logs,the upper Hesan member of Paleogene system in Shuanghe-Zhaoao area in Biyang fault basin can be divided into three secondary-type sequences;and spatially,there are following sedimentary series from south to north in this basin:alluvial fan,fan delta,lake sediments and delta. Thus there exist four depositional system tracts of landfacies sequence in Biyang fault basin,therefore forming four subsequences which are lowstand aggradation,regressive deposition,highstand aggradation and ingression deposition. Having analysed the seismic facies lateral characteristics of Hesan member of Paleogene system,with a good use of drilling,log and geology data in this area,we converted its seismic facies into relevant sedimentary facies,from which the depositionai model of Hesan member in this area was derived desirably.A lithofacies frame model of land facies formation in the Biyang basin was made in terms of the common development characteristics of three land-facies sequences of the interested object interval. Then,an age stratigraphic frame model of object interval was obtained by doing sequence correlation of seismic section that goes through boreholes.
