Study On Seismic Prediction Methods Of Fengle West Thin Reservoir

The study area is located at the southern end of Sanzhao Sag in the central depression of Songliao Basin,and is a second-order negative tectonic unit.The main target layers in the study area are delta facies deposits.The mud-encased sandstone deposits are shown on the mud logging.The thickness of the single layer of sandstone is generally between 1m and 2m,and generally does not exceed 3m.From the resolution of seismic data,its main frequency is about 40 Hz.In view of the deep burial and thin reservoir characteristics of Putaohua reservoir in the study area,this paper makes full use of geological,seismic and logging data,completes fine structural interpretation on the basis of fine stratigraphic correlation and division scheme,and carries out model-based logging inversion by using the contrast analysis method of controlling the unique variable.Geostatistical inversion and seismic waveform indication inversion are the three most important seismic inversion methods.Study on the prediction effect of thin reservoir with good inversion parameters.Through the comparative analysis of profiles under different inversion parameters and combined with logging lithology information,the parameters of three inversion best inversion effects are determined.Through the comparative analysis of the three inversion best inversion profiles,the best seismic inversion method and inversion parameters suitable for the study area are finally determined,and the thin reservoir prediction under the optimal inversion scheme is verified by combining the lithology information of the posterior well.Through comprehensive comparative analysis of inversion results,it is found that although model-based logging inversion can obtain high-resolution inversion results,the inversion results are vulnerable to the influence of the initial model.Because the target reservoir is thin and the transverse continuity is poor,and the spacing between wells in the study area is relatively large,there is a significant gap between the established initial model and the real situation.Therefore,this method is serious on modeling in this area and the results have obvious multi-solution characteristics;The results of geostatistical inversion are less affected by the quality of seismic data,and can obtain high-resolution inversion results which are in good agreement with wells,but the inversion results depend on the accuracy of variation function,and have higher requirements for the number of points in the work area and the distribution between wells;the inversion results have strong randomness and relatively well-controlled spacing.The accuracy of inversion results in large research areas is not ideal;seismic waveform indication inversion uses seismic waveform characteristics instead of variogram function to characterize the change of reservoir spatial structure,improves the lateral resolution of inversion results,and is more in line with plane geological law.At the same time,the inversion method has no strict requirements for well location distribution,mainly based on the change of seismic waveform and the development structure of reservoirs.The relationship inversion of reservoir thickness is more suitable for the relatively small well control spacing,thin reservoir development and poor lateral continuity in the study area.