Abstract:Because China has some of the most water-flooded oilfield in world, stable oil production relies on controlling water injection and increasing oil recovery. The sandstone stacked styles, heterogeneity, geometry of reservoirs can be studied by high resolution sequence stratigraphy with a kind of new vision, which closely links remaining oil distribution and extends new method for studying remaining oil distribution. This paper studies base level changing laws of different cycles based on detailed research of sedimentary micro-facies of Karamay formation, then the short base level cycles of Karamay formation can be divided into 2 main classes and 12 small classes. The middle base level cycles control the development of short base level cycles, so the Karamay formation can be divided into 3 middle cycles and 14 short cycles, then the isochronous stratigraphic framework are built. The short base level cycles which are located in the middle base level cycles have different remaining oil distribution in isochronous stratigraphic framework. The result shows that the detailed sedimentary work is the base for studying sequence stratigraphy. The reservoirs that are deposited in the high accommodation can have good isochronous and low intraformational heterogeneity, so, the remaining oil distribute in thin, small, nonproducing or low degree of water flooded area. Meanwhile, the reservoir that is distributed in low accommodation can have poor isochronous and high intraformational heterogeneity, and which are composed of noncontemporaneous deposit, so, the remaining oil is distributed in low permeable reservoirs in form of lens.