Multi-layer Tomography and its Application for Improved Depth Imaging

Patrice Guillaume, Steve Hollingworth, Xiaoming Zhang, Anthony Prescott, Richard Jupp, Gilles Lambaré, and Owen Pape
CGGVeritas, Crompton Way, Crawley RH10 9QN, UK ; +44 1293 683162

The application of a new ray-based multi-layer approach for reflection tomography overcomes many of the limitations of tomographic methods typically employed on Pre Stack Depth Migration (PSDM) projects. Global tomography is unable to accurately represent major velocity and anisotropy contrasts within the framework of a cell based model representation and will not correctly reposition layer boundaries during the inversion process. These limitations necessitate the use of a layer stripping workflow on areas with a complex layered geology. However, such a workflow is time consuming and prone to velocity errors being propagated into deeper layers as the model building progresses. Multi-layer tomography, using a new hybrid model representation, allows layer boundaries to be accurately represented and repositioned by map migration within the inversion. This allows all units in a complex layered model to be updated simultaneously and avoids the need for a layer stripping workflow. This results in a more efficient velocity inversion workflow and improved quality of both models and imaged seismic data.

AAPG Search and Discovery Article #90160©2012 PAPG/SPE Annual Technical Conference, 3-5 December 2012, Islamabad, Pakistan.