Research On Sedimentary Mode Of Reservoir In The North Of Saertu Development Area Of Daqing Oil Field

Since the beginning of the ’Eleventh-five-year Plan’, every development system of Sabei development area has been in the phase of super-high water cut period. With the accession of water cut,with the deepening of the tertiary oil recovery, the distribution of remaining oil gradually becomes complex day by day and with the raising of reconation towards the prision and deepness of depositions, investigations should be done in reservoir dissection.As the exploitation of oil and gas field in Sabei development area is rapidly developing,the effective prediction of distribution of interwell sandbody has become an urgent issue in achieving effiecient exploitation and improving oil recovery in dense well pattern.Based on the integrated information of dense well and seismic data, a study of interwell reservoir prediction in super high water cut area was carried out. On the basis of high resolution sequence and fine fluvial facies sedimentology, according to correlation principle:the cycle contrast, the step control, different treatment for different phase belt and sedimentary system of fluvial-delta, we take advantages of basic information such as well log, coring, seismic data, performance data and sand body dissection method of "the model prediction, the step control", we depict sedimentary unit, sedimentary microfacies, single channel sandbody, single channel inner sandbody step by step, classify different sedimentary model of reservoirs, explore a fine method of reservoir depiction in dense well pattern.Based on the high resolution sequence stratigraphy framework of the whole area we build, we distinguish20microfacies and make it clear that areal(plane) tendency of reservoir and the sedimentary environment in each time units in Sabei development area, and then, we analyze the relationship between depositional pattern,reservior heterogeneity and the distribution of remaining oil. After that, we establish the vertical evolution sequence of reservoir deposition. In accordance with the analysis and the distance between reservoir and lake strandline,We summarize9sedimentary pattern in channel sandbody of Class Ⅰ, Ⅱ, Ⅲ. The Class Ⅰ oil reservoir includes two depositional models:flooding plain areaceous braid river and meandering river. The Class Ⅱ oil reservoir consists of three depositional models:delta distributary plain offshore, midshore and onshore overwater distributary channel sandbody. The Class Ⅲ oil reservoir mainly involves four depositional models:delta inner front offshore, midshore, onshore underwater distributary channel sandbody and delta outer front sand sheet. In this paper, firstly we explore a regular pattern of fluvial areaceous braid river channel bar, braided channel and single channel in meandering river in the Class Ⅰ oil reservoir. Moreover we highlight depositional models of the Class Ⅱ oil reservoir, in the study area, the Class Ⅱ oil reservoir mainly includes delta distributary plain overwater distributary channel deposits, whose scale is smaller, thickness is thinner, physical property is worse, the mount of layers is more, areal heterogeneity is stronger than the Class Ⅰ oil reservoir, while in offshore overwater distributary channel, the point bar and abandoned channel develop very well. At last, we analyze the origin and areal tendency of reservoir sandbody,in order to satisfy the need of further oil development, we launch a research of the relationship between different reservoir depositional model,reservoir heterogeneity and the distribution of remaining oil.