HIGH-RESOLUTION CROSSWELL IMAGING OF A WEST TEXAS CARBONATE RESERVOIR.2. WAVE-FIELD MODELING AND ANALYSIS

We have collected low-noise crosswell data in a high-velocity carbonat e environment with a spatial sampling interval of 2.5 ft (0.76 m). Thi s sampling reveals a variety of coherent events not previously identif ied in coarsely sampled gathers. Nearly every event in our field recor d can be explained using simple approximations for the geology, source , and receivers without accounting for the presence of the boreholes. We have used synthetic records as a guide in a moveout-based analysis of the field data. Our analysis shows that much of the full wavefield energy, i.e., scattered waves, in our data are converted modes arising from the direct P- and S-waves. This observation suggests that for cr osswell reflection imaging, the focus of acquisition and wavefield sep aration techniques should be on the suppression of once-converted mode s.