MultiFocusing Time and Depth Imaging

The Zero-Offset MultiFocusing (ZOMF) approach constructs each zero-offset trace by stacking traces whose sources and receivers fall within a defined aperture around the imaging point. Unlike conventional CMP stacking, traces need not belong to the same gather — this substantially increases the stacking power and signal-to-noise ratio by utilizing data from many neighboring CMP gathers simultaneously.

ZOMF uses a three-parameter traveltime surface that accurately approximates actual traveltimes in the vicinity of the imaging point. These parameters — the emergence angle and two radii of curvature representing fundamental wavefronts — enable stretch-free moveout correction that preserves vertical resolution, unlike conventional NMO which suffers from wavelet stretch at far offsets.

Common-Offset MultiFocusing (COMF) generalizes the approach for prestack applications, enabling non-hyperbolic imaging, prestack signal enhancement, and amplitude-versus-angle (AVA) analysis. The five-stage MF workflow progresses from prestack data binning through MF parameterization, data analysis, prestack enhancement, and final imaging with velocity corridor picking.