Seismic redatuming with transmission loss correction in complex media

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Abstract

Traditionally redatuming algorithms disregard amplitude information carried by seismic reflections, they focus just on traveltime information. Properly processing amplitude information requires much more computing resources. We develop an algorithm for redatuming that aims to preserve amplitude information. We aim to observe energy conservation while undoing the propagation effects between the actual acquisition level on the surface, the original datum, and a hypothetical acquisition level buried in the subsurface, the new datum. Conventional redatuming amounts to correlation of the reflection measurements with the up and down going transmission responses of the medium between the original datum and the new datum, the overburden. Even using exact Green's functions, conventional redatuming distorts amplitude information. Energy lost in transmission through the overburden, that is the energy reflected by the overburden, is not accounted for. In terms of flux normalized one-way wave fields in laterally varying media, C.P.A. Wapenaar derived a correction for these transmission losses. Chapter 5 describes an optimized implementation of this correction. Chapter 6 shows how to estimate the reflection response of the overburden from the measured reflections. In Chapter 7 we extend flux normalized wave field decomposition to curvilinear coordinates. This allows redatuming between curved datums.