f Comparison of VSP and Sonic-log Data in Nonvertical Wells in a Heterogeneous Structure

In borehole geophysics, sonic-log measurements and vertical seismic profiling (VSP) are two<br>techniques which provide information about the seismic velocity in the structure surrounding<br>a particular well. These techniques use significantly different frequencies of seismic signals.<br>The results of sonic-log measurements may thus differ from the results of VSP by the velocity<br>dispersion. To compare the results of the two measurements, the sonic-log velocities are used<br>to estimate corresponding sonic-log traveltime in the geologic structure, which is then<br>compared with VSP traveltime.