Oil and Gas
Oil and Gas | Geophysics and Seismic Interpretation
Business impact: Through technological advances in acquisition, imaging, and computing, we are now increasingly able to correctly depict complex subsurface scenarios and image structures that were previously invisible. Throughout the course, the interaction between the imaging process and the art (and science) of the interpreter will be emphasised.
This is an advanced course beginning with the theoretical basis of the seismic reflection image and working through a systematic description of the principal techniques deployed by today’s seismic processors to image complex subsurface structures in time or depth domains. This course will allow participants to evaluate the potential value of competing techniques and gain a greater understanding of the issues in complex velocity model building.
Imaging of seismic data in both time and depth will be explained, with their disparity in accuracy, but commensurate difference in time and effort required. This is because time-imaging encapsulates its velocity analysis, albeit with an associated reduction in quality, while depth-imaging involves explicit velocity model definition and includes time-to-depth conversion.
Duration and Training Method
A classroom course comprising a mixture of lectures, case studies and classroom exercises.
Participants will learn to:
- Understanding the nature of what constitutes the reflection seismic image.
- Foundations: wave equation, propagation velocity, seismic anisotropy, wavefield and rays, sorting data for imaging and wavefield seperation.
- Ray-based depth migrations: the Kirchhoff method versus the various Beam techniques.
- The assumptions, benefits and limitations of Pre-stack Time Kirchhoff migration.
- Wavefield Extrapolation based migrations (WEM and RTM): the benefits and issues associated with each imaging method.
- How do we go about the building of complex velocity models? Ray-based linear and non-linear tomography and WE-based methods. Assessment of anisotropic parameters with borehole control and uncertainties.
- The principles and potential of Full Waveform Inversion illustrated by examples in various contexts.
- Importance of acquisition style, multi- and especially wide azimuth.
- The intrinsic link between the depth imaging process and the interpreter in the workflow.
- Understanding the nature of what constitutes the reflection seismic "image"
- Overview of current Pre-stack Depth imaging techniques; Ray-, Beam- and Wavefield Extrapolation-based methods
- The specific case of Pre-stack Time Migration
- The benefits and issues associated with each imaging method
- The key imaging parameters that drive success in the imaging process
- Importance of acquisition style in imaging, especially wide-azimuth shooting
- How do we go about the building of complex velocity models? Various tools and workflows
- Borehole control for the estimation of anisotropic parameters (epsilon and delta fields)
- The potential of Full Wavefield Inversion
- Recent developments in depth imaging: wavefield separation; least squares migration; imaging with surface-related multiples; assessment of uncertainties
- The intrinsic link between the imaging process and the interpreter in the modern workflow
Who Should Attend and Prerequisites
Those geoscientists either working with, or supervising, projects involving complex subsurface velocity model-building and imaging challenges.
Etienne Robein graduated from Ecole Nationale Supérieure d’Aéronautique et Espace and Ecole Nationale Supérieure Pétrole et Moteurs / IFP in Paris in 1973. He started his career with Shell in The Hague, before joining Elf and then Total at the merger, where he has worked on operational, research and managerial assignments in France, Italy, the United Kingdom and Azerbaijan. His professional experience covers seismic acquisition, processing and interpretation. In recent years, he was Director of the Total Geosciences Research Centre in London. His last position with Total was R&D program manager in Geology and Geophysics. He now works as a free lance tutor in Geophysics.
Etienne is the author or co-author of several presentations in International Conferences, including the SEG, EAGE, WPC, AAPG, and Petroleum Geology Conference and contributed to the EAGE’s “Distinguished Lecture Program” and “Education days”. In 2003, he published a text book on “Velocities, Time-imaging and Depth-imaging in Reflection Seismics,” which became a best-seller EAGE Edition, and in 2010 a textbook on “Seismic Imaging, A review of the Techniques, Merits and Limitations” with the same editor.
Affiliations and Accreditation
EAGE - President (2000)
EAGE - Honorary Member
EAGE Research Committee - Former Chairman
SEG Council - Former Europe’s Representative
N217: Modern Seismic Imaging Techniques: A Masterclass in Time and Depth
N317: A Practical Introduction to Depth Imaging for Interpreters