Integrated Research On Seismogeological Characteristics Of Niujuanhu Area In Malang Depression

Based on high-resolution seismic data and guided by depositional system analysis and sequence stratigraphy theory, this paper takes the established sand body matrix model and pool-forming mode as reference and combines the technologies of depositional system analysis and seismic reservoir prediction to perform sand-body and physical property characterization and prediction and evaluate the hydrocarbon bearing feature, finally realizing lateral reservoir prediction. This paper completes comprehensive interpretation of 3-D seismic data in Niujuanhu area by use of LandMark system based on the seismogeological knowledge and known information of drilling and oil production. By making synthetic seismic record of well data,a fine horizon calibration for the strata of Cretaceous and Jurassic are made. On the basis of the calibration, a fine interpretation of the horizons and faults and the structural drawing are also made, then the structural features of the well area are briefly analyzed. In order to improve the quality and accuracy of velocity analysis, the method and flow chart of velocity analysis have been developed and the variation rule of average velocity of every target within the zone has been researched. The 3D velocity field of the target area has been established and the variable velocity restitution of each horizon in target zone has also been accomplished. The accuracy of structure elucidation is further improved, and the structural features of the well field have been briefly analyzed. Based on the structural interpretation, a reservoir inversion of the study area has been made using logging data as a binding condition. The approach of model inversion under the bind of logging data is researched, which is a indirect method of poststack inversion based on model superimpose and uses 1D convolution model as theoretical base, the approach implements the inversion of constrained sparse impulse using a nonlinear optimal algorithm based on the norm of least square and introducing the interpretation results seismic sequence and acoustic impedance log as constrained boundary condition. This algorithm has strong counter-interference capability and isn't limited to seismic bandwidth as well as doesn't introduce seismic noise, etc. We also optimize inversion parameters and analyze whether the inversion results are correlated to the acoustic impedance log and seismography and the degree of their deviation by taking erroranalysis. The neural net and multiple seismic attribute analysis method are researched in reservoir inversion. The flat distribution regularities of the reservoir thickness of QiGu formation,TouTunHe formation and XiShanYao formation have been obtained, and the flat distribution characteristics of reservoir physical features have been described. All this work provides more favorable foundation of improving precision in reservoir exploration of oilfield in the future.