Abstract：Based on analyzing the characteristics of borehole VSP observation system, the authors investigated the types and features of the observed seismic waves, analyzed ray-tracing and composite records of several VSP models (horizontal interface model, oblique interface model, meta-deviation distance model and detection point model), conducted forward modeling by using the ray-tracing method so as to obtain the forward result, and studied kinematic characteristics of the seismic wave. Some regularities have been detected: the number of the strata penetrated by the drill hole is equal to the number of intersecting points between the ascending waves and the descending waves in the composite record; there exist differences between the composite ray-tracing record obtained by utilizing P wave and that obtained by utilizing the transform wave, which shows that the transform wave has some influence on VSP composite record; strata of different dip angles have influence on travel-time features of ascending wave and descending wave as well as the energy characteristics of VSP; there exist reverse polarity phenomenon on the horizontal component of VSP composite record, which is consistent with the theoretical phase.
