3D plane-wave migration in tilted coordinates: A field data example

摘要

We have extended isotropic plane-wave migration in tiltedcoordinates to 3D anisotropic media and applied it on a Gulfof Mexico data set. Recorded surface data are transformed toplane-wave data by slant-stack processing in inline andcrossline directions. The source plane wave and its correspondingslant-stacked data are extrapolated into the subsurfacewithin a tilted coordinate system whose direction dependson the propagation direction of the plane wave. Imagesare generated by crosscorrelating these two wavefields. Theshot sampling is sparse in the crossline direction, and thesource generated by slant stacking is not really a plane-wavesource but a phase-encoded source.We have discovered thatphase-encoded source migration in tilted coordinates can imagesteep reflectors, using 2D synthetic data set examples.The field data example shows that 3D plane-wave migrationin tilted coordinates can image steeply dipping salt flanks andfaults, even though the one-way wave-equation operator isused for wavefield extrapolation.