Rigorous redatuming

Abstract

Redatuming is an operation on seismic data that translates the positions of sources or receivers, or both. Here, redatuming is applied to shift sources and receivers to a specified depth with the aim to completely remove the effects of a complex overburden. To that end, redatuming was formulated as an inverse problem for the full acoustic wave equation, including multiples, without making simplifying assumptions such as downgoing waves or primaries only. The inverse problem is ill posed, but quite acceptable results on synthetic data were obtained with a suitable regularization. One might expect that the redatumed result would also i nclude waves that move up into the overburden and are reflected back to the redatuming depth. It turns out that these waves are automatically removed by the redatuming, without the need for special filters or up-down decomposition. © 2005 Shell International and Production B.V.