Sedimentary Facies Study And Seismic Reservoir Prediction Of Fuyu Reservoir, Xingshugang 3D Seismic Survey, Changyuan Anticline, Daqing Oilfield

Xingshugang 3D seismic survey, which covering an area of about 520 square kilometers, is located in north-central Changyuan anticline, Central depression, Daqing oilfield, Songliao basin. The target stratum, Fuyu reservoir belongs to the 3 rd and 4th members of Quantou formation, medium Cretaceous. It became the hot spot in exploration of Daqing oilfield in recent years because it’s excellent structural and accumulation conditions.According to the core and well log data, a conclusion is drawn that the Fuyu reservoir is dominated by fluvial deposits. The channels developed in upper section of Fuyu reservoir present typical bell-shape in log curves and obvious fining-up trend in grain size. These are consistent with the characteristics of meandering channel. However, those channels in lower section are box-shaped at bottom and bell-shaped in upper part in log curves. Grains of the channel sands are finer, and more mud in vertical sequence. So, the channels developed in lower Fuyu reservoir are transitional-type ones which show characteristics of both meandering and anastomosed rivers. Afterward, the base-level cycles of all scales of Fuyu reservoir are recognized applying high-resolution sequence stratigraphy theory and these stratigraphic cycles are correlated across wells and facies succession to erect chronostratigraphic framework of Fuyu reservoir, which is particularly important for the following work.Based on the sequence stratigraphic framework and reflection features of Fuyu reservoir, well-seismic calibration and horizons interpretation were done precisely. Reasonable smooth and interpolation are necessary to make sure the seismic horizons match the actual surfaces well. And then, many kinds of seismic attributes were extracted through the time widows which are defined by the interpolated seismic horizons. By comparing seismic reflection with well log curves and lithologic data, the geologic meaning of seismic attributes is given. Sedimentary facies prediction was done under the guidance of seismic attributes distribution.Building correct low-frequency model under the constraint of well log curves and selecting appropriate wavelet are very important to constraint sparse spike inversion. To achieve the best inversion results, the whole process is carried out under strict quality control which present how does the inversed model match the actual seismic data. At last, sedimentary facies of Fuyu reservoir was predicted based on the analysis of the correlations between inverted impedance and well logging data and seismic attributes.