Full Waveform Inversion

by Mrinal K. Sen

Duration: One to two days

Intended Audience: Entry and intermediate levels

Prerequisites (Knowledge/Experience/Education Required): The course is designed to be followed by anyone with some background in seismic processing including imaging. Basic understanding of the physics of wave propagation is required.

This course is designed for technical personnel of the oil and gas industry who are engaged or expected to be involved in seismic imaging, accurate velocity analysis and interpretation. Seismic Inversion plays an important role in building reservoir models by integration of different data types.

The course will begin with a comprehensive review of elastic wave propagation, which is fundamental to understanding inversion algorithms and results. Several pre-stack and post-stack inversion methods will be reviewed. Theory and application of 1D full waveform inversion will be discussed, which will form the foundation of 2D/3D full waveform inversion. The current state of FWI is acoustic formulation with application to accurate imaging and velocity estimation. Several algorithms in time and frequency domain and their limitation will be discussed with examples. Effect of ignoring parameters such as density and the choice of a starting model will also be elaborated.

Learner Outcomes:
At the end of the course the student will be able to:

  • Explain the motivation behind FWI and the basic requirements for inversion.
  • Recognize the need for full waveform modeling.
  • Identify the approximations and limitations of different methods.
  • Demonstrate how to formulate an inverse problem.
  • Describe the difference between linear and non-linear methods, local and global optimization.
  • Explain different methods of seismic inversion in 1D & the limitations, the need for a FWI and its limitations.
  • Discuss the theory and implementation of FWI, the need for this technology, and its limitation.
  • Critical issues: computation, choice of a starting model, use of acoustic FWI.

Teaching Methods:
Students will experience lecture on theory and application, discussion of flowcharts, seismic images and inversion results. Course participants will receive course notes.

Instructor Biography:
Mrinal K. Sen