The Relationship Between Sonic Logging Velocity And Seismic Velocity

For underground medium,the propagation velocity of mechanical vibration is usually frequency-dependent,which is the phenomenon of dispersive media,and the relationship between speed and frequency is nonlinear.Due to the existence of the phenomenon of dispersion,velocities extracted from the logging data and seismic wave velocity are different.Also,because the nonlinear relationship between the two velocities,this relationship is not the same for different lithologies,so the seismic velocities cannot be obtained directly from sonic speeds,thereby reducing the sonic log data's application to determine seismic velocity.Since the actual seismic trace recording and synthetic seismograms made by logging data are different in phase,frequency and scale etc.,which results in a large difference between seismic velocity and the sonic velocity at the corresponding formations.Therefore,the interval velocity detected by the two technologies cannot be used for calibration of each other.Otherwise,it will bring large error,which reduces the utilization of the field data.The major work of this thesis is to study the actual sonic log data and real seismic data first,then extracts the interval velocity respectively,after studying and comparing the relationship between them and trying to explore the function mapping relationship between the two velocities,then we take pre-stack depth migration using the corrected velocity,then determine the optimal mapping relationship through the final effect,so as to achieve efficient use of sonic log velocity in establishing seismic migration velocity model.