The objective of seismic imaging is to get a sharp and accurate image of the elastic reflectivity in the subsurface, especially in complex geological settings. By ‘accurate’, we mean that reflectors should be at the right depth, but also correct lateral position.
The accuracy of a Pre-Stack Depth Migration image goes together with our ability to estimate the velocity at which waves propagate in the subsurface. To build such a Velocity Model remains a challenge because the earth is not only heterogeneous (waves propagate at different velocities at different locations), but also anisotropic (propagation velocity is a function of propagation direction).
The presentation discusses the physical meaning of Thomsen’s parameters epsilon and delta included in the Model to describe anisotropy. It illustrates a popular method to estimate them in a Pre-Stack Depth Migration project to conclude that borehole calibration is a necessary step to achieve the best accuracy possible.
This video is part of EAGE Online Education Programme.
The European Association of Geoscientists and Engineers (EAGE) is a global professional, non-profit association for geoscientists and engineers. EAGE strives to promote innovation and technical progress and aims to foster communication and cooperation between those working in, studying or interested in these fields. To learn more about EAGE Education visit www.LearningGeoscience.org
The following courses by Etienne Robein are available via EAGE:
– Seismic Imaging: A Review of the Techniques, their Principles, Merits and Limitations (EET 4)
– Seismic Depth Imaging and Anisotropic Velocity Model Building