Imaging the Earth in one sweep: time extrapolation of the full source/receiver wavefield

 By

Prof. Tariq Al-Khalifah

Professor of Geophysics

at

King Abdullah University of Science and Technology

Date & Time: Tuesday, April 26, 2011 at 4:15 pm

Location:         Lecture Hall 1, Building 9 (Engineering Science Hall)

Refreshments to be served at 4:00 pm

Abstract

Unlike prestack imaging using the conventional wave equation, which requires an integral based imaging condition, imaging using the double square (DSR) equation avoids that requirement and thus provides an explicit relation between the imaging operator and medium parameters. Thus, while most of the modern seismic imaging methods perform imaging by separating input data into parts (shot gathers), we develop a formulation that is able to incorporate all available data at once while numerically propagating the recorded multidimensional wavefi eld backward in time. While computationally extensive, this approach has the potential of generating accurate images, free of artifacts associated with conventional approaches. However, DSR suffers from and inherent singularity when waves travel horizontally. We explain this singularity, show its extent, and the limits on offset and dip treated because of this singularity. Our analysis covers both laterally homogeneous and inhomogeneous media, and thus, we show the behavior for lateral inhomogeneous media is different. A numerical extrapolation shows the evolution of the wavefield in the prestack domain using a prestack exploding reflector modeling experiment.