Joint application of VSP and sonic logging data in lithologic interpretation

Variations of formation velocity are closely related to the changes of formation lithology. Precision a nalysis of velocities from VSP and sonic logging data shows that the using of these two kinds of velocities individually in lithologic interpretation is insufficient and unreasonable. Before being used, the sonic wave data must be corrected. Practice has proven that interactive velocity analysis of these logging data is an effective method in areas with several wells, yielding an accurate distribution of velocity lithological variation. Therefore, the precision of lithologic interpretation can be improved