f Tutorial interpretive evaluation of migrated data

In practice, decisions with regard to migration include choice of migration strategies (2-D/3-D, poststack/prestack, time/depth), migration algorithms (integral, finite-difference, frequency-wavenumber) , parameters for a given algorithm (aperture width, depth step, stretch factor), factors related to input data (profile length, spatial sampling, noise), and most importantly, migration velocities (the weak link between seismic and geologic sections). By using a large number of field data examples, the problem of conflicting dips with different stacking velocities and that of strong lateral velocity variations associated with complex overburden structures will be discussed. Emphasis will be made on uncertainties in migration velocities and interpretive evaluation of the results we obtain from migration.