Velocities, Imaging, and Waveform Inversion - The Evolution of Characterizing the Earth's Subsurface
|Instructor||Dr Ian Frederick Jones (ION, UK)|
|Book||Will be available in EAGE Bookshop|
Ian Jones' two-day course 'An introduction to migration and velocity model building' covers much of the ground that this EET will cover, as does Etienne Robein’s EET 4 course on imaging, Tariq Alkhalifah's EET10 course and Jean Virieux’ SEG DL course on FWI. However, this new EET will be a fusion of the practical industrial elements of the above courses, concentrating on the origin and nature of the geological complexities that give-rise to imaging problems, as well as a physical (rather than mathematical) understanding of subsurface parameter estimation, and will also look at some possible future directions.
The course is designed for: practising geoscientists who desire to better understand the principles and limitations of both current and emerging technologies involved in subsurface parameter estimation and imaging, and geoscience students. Following this course, participants should ideally understand how contemporary velocity estimation methods work, and what approximations are involved in obtaining computationally tractable solutions.
In using sound waves to characterize the Earth's subsurface, we can employ ray-theory and/or wave-theory, and both migration algorithms and parameter estimation schemes employ one or other of these theoretical descriptions. In this course, we'll review the evolution of the industry's approaches to building earth models via velocity estimation and imaging, outlining the evolution from ray tomography to full waveform inversion, and look towards the emerging possibilities for replacing imaging techniques with direct subsurface parameter inversion methods.
The approach will be mostly non-mathematical, concentrating on an intuitive understanding of the principles, demonstrating them via case histories, and will be divided into the following sections:
- dealing with the near surface
- the effects of strong vertical velocity contrasts
- the effects of strong lateral velocity contrasts
- waves versus rays
- model building using ray methods (tomography)
- model building using wavefield extrapolation methods (FWI)
- data examples and comparisons
- future developments
The first three sections outline the nature of the problems we face when building images representing subsurface impedance contrasts, and the next three deal with the technology we deploy to address the problems. In addition, I’ve included three appendices to outline: the historical development of model building; anisotropy; and pre-processing considerations for complex imaging. Several of the individual chapters build on a series of recent tutorial papers which I published in First Break. However, only the key points from these tutorial papers are included, so I refer readers to the original papers for more detail and/or a range of real data examples for each of their topics.
Due to space and time constraints in the EET format, Ian Jones had to omit or limit coverage of various topics, including: migration of multiples, Marchenko and inverse scattering series migration, joint migration-inversion, least-squares migration, and uncertainty estimation.
The course is designed for practising geoscientists who desire to better understand the principles and limitations of both current and emerging technologies involved in subsurface parameter estimation and imaging, and geoscience students.
A general knowledge of geophysics.
About the instructor
Ian F. Jones received a joint honours BSc in Physics with Geology from the University of Manchester, UK, in 1977, an MSc in Seismology from the University of Western Ontario, Canada, and a PhD in Geophysical Signal Processing from the University of British Columbia, Canada. After working for ‘Inverse Theory & Applications Inc.’ in Canada for two years, he joined CGG, where for 15 years he was involved in R&D in the London and Paris offices, latterly as manager of the depth imaging research group. Since 2000 he has been with ION GX Technology, as a Senior Geophysical Advisor in their London office.
His interests include velocity model building and migration, and his most recent activity includes writing the text books: ‘Velocities, Imaging, and Waveform Inversion: the evolution of characterising the Earth’s subsurface’ published by the EAGE in 2018; ‘An Introduction to Velocity Model Building’ published by the EAGE in 2010; and co-editing the SEG Geophysics Reprints series volumes ‘Classics of Elastic Wave Theory’ and also ‘Pre-Stack Depth Migration and Velocity Model Building’, as well as contributing the chapter on model building to the new SEG online encyclopaedia.
He is an associate editor for the journals ‘Geophysics’ and ‘Geophysical Prospecting’, and teaches the EAGE/PESGB/SEG continuing education course on ‘Velocity Model Building’ and is an external lecturer at the University of Leeds and Imperial College London. Ian was awarded the EAGE’s Anstey Medal in 2003 for contributions to the depth imaging literature, made the SEG European Honorary Lecturer in 2012, conducted the 2018-2019 EAGE international Education Tour, and was made an Honorary Life Member by the EAGE in 2018.
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