| There are good conditions for the formation of subtle reservoirs in Gaojiapu area of Baxian Depression. The study on the exploration of subtle reservoirs is getting more and more important as the exploration of the conventional structural reservoirs is harder than before. Based on the classical theory of sequence stratigraphy and the data of seismic, well log and core, the lower part of the first member of Shahejie Formation (Es1x) to the fourth member of Shahejie Formation (Es4) have been divided into seven third-order sequences. The third member of Shahejie Formation (Es3) which is the target formation of this paper has been divided into three third-order sequences, including sequence 3, sequence 4 and sequence 5. They are lacustrine sequences which developed during the period when faults moved intensively. According to the core observation and analyses of facies marks, Es3 mainly developed fluvial deltas-fluxoturbidite, nearshore subaqueous fan, littoral-shallow beach-bar and semi-deep lake-deep lake sedimentary systems. Corresponding sedimentary models are also built. The first ever discovery of fluxoturbidite in this area is very important for the exploration. There are two provenances in Es3 period. One is Niutuozhen salient in the west which provides sediments to nearshore subaqueous fan sedimentary system, and the other is Wenan slope in the east which provides sediments to fluvial deltas-fluxoturbidite sedimentary system. According to the analyses of the Palaeogeomorphology, seismic attributes and the isopach of ratio of sandstone and formation, we finished the sedimentary facies maps of every systems tract within the sequence stratigraphic framework. We sumed up the sedimentary system distribution rule, and it is helpful for the prediction of the potential sandbodies. After the analyses, we hold the viewpoint that the controlling factors of the sedimentary system are the provenance, the palaeoclimate, the palaeogeomorphology and the fault activities.
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