Abstract: The velocity field produced by conventional methods does not meet the accuracy requirement for the detection of structure and formations in horizontal well drilling in shale gas exploration.In this paper, we present a 3D interval velocity field building method based on comprehensive analysis of the following data:stacking velocity, logging data, structural interpretation results and seismic data.We adopted several techniques for estimating the interval velocity for the proposed method, namely, the Dix formula, the constrained Dix formula, model tomography, and wave impedance inversion.First, we divided the formation into upper and lower strata according to the initial depth of logging data.Then, for the upper strata, we use the first three conventional techniques mentioned above to estimate its interval velocity based on stacking velocity and structural interpretation results.We use the wave impedance inversion for the lower strata to obtain its interval velocity based on 3D post-stack seismic data, logging data, and structural interpretation results.Finally, we combine the upper velocities estimated via the three techniques and the inverted lower velocity.We then select the best combined interval velocity in the study area.This method takes advantage of the high-resolution wave impedance inversion.The test results of seismic data in the Fuling shale gas field showed the decrease in depth error between the depth structure map from the velocity field obtained using the proposed method and the shale formation depth measured by drilling, which indicates that this method is practical for the exploration and development in the Fuling shale gas field.