Application Of Geostatistical Inversion In Dolomite Reservoir Prediction In SYS Area

With the development of the society,the demand of the petroleum is keeping growing,which means the exploration turns to be deeper and more complex.Thus the increased difficulty is followed behind.As one of the most sign-ificant mean for reservoir prediction,the seismic inversion technique plays a r-ole in the progress of the prediction.The post-stack impedance inversion is the most widely applied technique of the post-stack inversion,it allows a good view of the transverse distribution of the reservoir.However,due to the limitation of the frequency band,the longitudinal resolution of the inversion is insufficient precisely.The geostatistical inversion technology based on the combination of geostatistical theory and stochastic simulation method can make full use of the high-resolution information of logging and seismic data,and add prior geological information to carry out stochastic inversion.It can not only obtain high-resolution wave impedance inversion body,but also carry out stochastic simulation of lithologic body.Aiming at the characteristics of dolomite reservoir of Qixia Formation in SYS area,such as thin thickness,deep burial,strong heterogeneity and difficulty in fine reservoir characterization,this paper expounds the method and principle of geostatistical inversion,discusses the prior geological information provided by constrained sparse spike inversion for geostatistical inversion,and compares and analyses the results of geostatistical inversion and constrained sparse spike inversion.The results show that the reservoir characteristics obtained by the two inversion methods are basically consistent with the reservoir intervals interpreted by logging,and show good continuity in lateral direction.However,the resolution of geostatistical inversion results is obviously higher than that of constrained sparse spike inversion.It absorbs the vertical high-resolution information of logging data and retains the advantage of lateral high resolution of seismic data.It not only achieves the degree of spatial distribution trend of reservoir reflected by constrained sparse spike inversion,but also can better identify the distribution characteristics of thin reservoir and effectively solve the problem which is prediction of dolomite thin interbeds of Qixia Formation in SYS area.Finally,structural and fracture analysis techniques are used to verify the reliability of the results of geostatistical inversion on the one hand,and comprehensive evaluation of dolomite reservoirs of Qixia Formation in SYS area on the other hand,which provides technical support for the study of dolomite reservoirs and methodological basis for oil and gas exploration in the study area in future.