Fine Characterization of Shallow Gas Velocity in the Yinggehai Basin Based on Three-dimensional First Break Wave Tomography Inversion
In view of the influence of shallow gas absorption and attenuation in the L gas field in Yinggehai Basin,the velocity of the shallow gas cloud area established by conventional methods such as velocity pickup or reflected wave tomography is inaccurate in the process of seismic data processing,resulting in the event pull-down of the shallow gas overlying strata,which affects the structural interpretation and reservoir prediction.In this paper,a solution based on three-dimensional first break wave tomography inversion is proposed,and the 3D seismic data in the L gas field experimental area of the Yinggehai Basin are processed and tested.The results show that the proposed scheme can accurately obtain the velocity model of the shallow gas cloud region,and the velocity accuracy is 9％to 15％higher than that of the conventional method.Pre-stack depth migration is carried out by using this velocity mod-el,the imaging gathers are flattened with the event,the imaging stack section is significantly improved,and the event of the shallow gas overlying strata is restored,which can better e-liminate the phenomenon of the event pull-down phenomenon of the shallow gas overlying strata on the seismic section,and provide more reliable seismic data for subsequent studies such as structural interpretation and reservoir prediction.
万方数据
维普
