Architectural boundaries of the fan delta front reservoirs in the quadrant Jin-99 of the Liaohe Oil Field,Liaoning

The Dujiatai oil reservoirs in the upper submember of the 4th member of the Shahejie Formation in the quadrant Jin-99 of the Liaohe Oil Field,Liaoning represent the representative fan delta front deposits,which are made up of the subaqueous distributary channel and channel bar deposits. According to core examination and well logs, 11 lithofacies types and 4 lithofacies associations are descriminated. Futhermore, in the light of high-frequency flooding surface,scour surface,sharp graded facies and lithofacies boundary,6 short-term and 15 ultrashort-term cycles are recognized for the I₃ and II₁ sandstone measures in the upper submember of the 4th member of the Shahejie Formation. Five-order architectural boundary systems are established for the fan delta front deposits within the isochronous stratigraphic framework,and two types of architectural boundary models are constructed. The results of research in this study may provide the basis for the establishment of the three-dimensional architectural models in the study area.