Full-Waveform Inversion: Where are the Anisotropic Parameters Hiding?
Course Description
The course starts by introducing the fundamentals of full-waveform inversion (FWI) starting from its basic definition. It focuses on the model update issues and provides analysis of its probable success in converging to a plausible model. In the course we will discuss the many challenges we face in applying FWI on seismic data and introduce modern day proposed solutions to these challenges. The focus of the course will be on FWI applied to anisotropic media. As a result, the course will also introduce anisotropy, its optimal parametrization and wavefield simulation in such media. Practical multi-parameter inversion for anisotropic parameters requires an optimal FWI setup. We will discuss such a setup, which includes the proper parametrization of the medium and data access scheme necessary for a potential convergence to a plausible anisotropic model.
Course Objectives
Upon completion of the course, participants will be able to understand: • The scientific foundation behind full-waveform inversion; • FWI challenges; • Wave propagation in anisotropic media; • Anisotropy + migration velocity analysis; • Anisotropy + FWI.
Course Outline
I - Introduction to seismic inversion: 1. What is inversion? 2. What do we mean by full waveform inversion? 3. The Algorithm. II - The elements of seismic waveform inversion: 1. Model and data. 2. The objective function. 3. The update. 4. The sensitivity kernel. 5. The non-linear issue. 6. Examples. III - Seismic anisotropy: 1. Definition and parameters. 2. The acoustic anisotropic wave equation. 3. Fundamental issues. IV - FWI and anisotropy: 1. Multi-parameter inversion. 2. The right set of parameters. 3. The anisotropic sensitivity kernels. 4. Getting an initial model. 5. Anisotropy and MVA.
Participants’ Profile
The course is designed for geophysics, mathematicians and physicists working on problems related to seismic imaging of the Earth and building the necessary velocity models to do so.
Prerequisites
Participants should have some knowledge on the physics of seismic wave propagation.
About the Instructor
Tariq A. Alkhalifah is a professor of geophysics in the division of Physical Sciences and Engineering at King Abdullah University for Science and Technology (KAUST). He assumed his duties there in June 2009. Prior to joining KAUST, Tariq was a research professor and director of the Oil and Gas Research Institute at King Abdulaziz City for Science & Technology (KACST). He has also been associate research professor, assistant research professor and research assistant at KACST. From 1996 to 1998, Tariq served as a postdoctoral researcher for the Stanford Exploration Project at Stanford University, USA. He received the J. Clarence Karcher Award from the Society of Exploration Geophysicists (SEG) in 1998 and the Conrad Schlumberger Award from the European Association for Geoscientists and Engineers (EAGE) in 2003. He is a member of SEG and EAGE. Tariq received his doctoral degree in geophysics (1997) and master’s degree (1993) in geophysical engineering from the Colorado School of Mines, USA. He holds a bachelor’s degree (1988) in geophysics from King Fahd University of Petroleum and Minerals, Saudi Arabia.