Advantages of High-density Wide-azimuth Slant Surveys for Steep-dip Subsurface Imaging

Narrow-azimuth orthogonal 3D/3C surveys impose a strong acquisition footprint on the PP and PS seismic datasets. This footprint is frequently manifested as false amplitude and phase variations in time sections and slices. The distribution of bin attributes can be improved using wide-azimuth receiver templates, especially in combination with slant or zig-zag shot lines. We illustrate the correctness of these recommendations by comparing effective fold and other bin attributes for two wide-azimuth surveys with the same aspect ratio of the receiver template (0.7). One of the surveys is an orthogonal one with the “standard” grid of receiver points (50 by 300 m) and the other survey is a slant one (45°) with a reduced interval between the receiver points (40 by 240 m). We have ray-traced both surveys to compare the synthetic PP and PS cubes and to show advantages of higher density wide-azimuth surveys for illumination of steep-dip targets.