Study On High-resolution Sequence Stratigraphy Of Putaohua Oil Layer In The Area East Of Xujiaweizi

The area east of Xujiaweizi is one of the most important exploratory area in northern Songliao Basin, producing Putaohua oil layer and Fuyang oil layer. This thesis mainly study the Putaohua oil layer. It is considered that the existing oil field has good potential for expansion through the recent drilling of the stepout wells out of the area and the detailed dissection of the dense well pattern. Aiming at solving some outstanding problems, such as small scale of sand body, thin reservoir thickness, complex relationship between water and oil, low reserves and the lack of systematic accumulation mechanism, this thesis establishes isochronal high-resolution sequence stratigraphic framework under the guide of theories and techniques of high-resolution sequence stratigraphy and the theories of sedimentology, using the full and accurate data about the core, drilling and logging of this area, and applying comparative technique of flooding surface standard that based on regional frame closed secant and controlled by the guiding bed, sedimentation model-contemporaneous fault model guiding, progressive propriety approximation, progressive sectional closure and asymptotical expansion and finally reach genetic mobile boundary. It will divide the Putaohua oil layer into nine small layers and twelve sedimentation time units in this research area and propose the stratigraphic model that southern layer is thinning down, Putaohua top and bottom is turning to mudstone and all layers is thinning down, pointing out that the main Putaohua oil layer in the research area is the river dominated shallow-water delta depositional system controlled by the southeast branch of source system in northern Songliao Basin. This thesis also dissections the sedimentary microfacies of this research area using the logging model of 1 phase,3 sub-phase and 10 micro-phase, further analyze the characteristics of the reservoir properties distribution, and reveals that the main layers are channel sand and sheet sand. It makes a comprehensive study on ancient structure, accumulation model, the controlling factors of accumulation and oil-gas accumulation regulation with the application of region accumulation comprehensive analysis technique, and determines the favorable exploration area, making full preparation for the further exploration and appraisal of well in the oil field.