John T. Etgen received a Bachelor of Science degree in Geophysical Engineering from the Colorado School of Mines in 1985 and a PhD in Geophysics from Stanford University in 1990. During his studies, he had the good fortune to work on a wide variety of topics in seismic imaging and data processing while learning from his mentors, Jon Claerbout and Norm Bleistein, along with many talented colleagues and fellow students. His thesis studied new-at-the-time prestack migration-driven tomographic techniques for velocity estimation. That experience taught him the true difficulties of inverse problems. Leaving Stanford behind, he began his industrial career in late 1990 at the Amoco Production Research Company in Tulsa, Oklahoma. Unlike many new PhD graduates, he did not want to continue to work on his thesis topic! Fortunately, once again he had the opportunity to work on a wide variety of topics and learn from leading researchers, such as Dan Whitmore, Rusty Alford, Kurt Marfurt, Ken Kelley, Sam Gray, and many others. In 1999, Amoco merged with British Petroleum (BP) and John moved to Houston, Texas. His role was senior scientist and then senior scientific advisor for seismic imaging at BP. In 2008, he and Carl Regone were awarded the Virgil Kauffman medal for their work in wide-azimuth marine seismic. In late 2011, John was appointed distinguished advisor for seismic imaging at BP. John currently serves as Assistant Editor for the scientific journal Geophysics and continues to work in the upstream technology organization at BP.
2019 SEG 3Q/4Q Distinguished Lecturer
Practical insights and techniques in seismic velocity estimation
The estimation of seismic wave speeds plays one of the most important and critical roles in seismic data processing. As we explore more complex and previously unexplorable provinces, as well as demanding ever-higher quality images from seismic reflection data everywhere, accurate velocity models are of paramount importance. I feel this topic is so important that everyone involved in creating images from seismic reflection data should understand the fundamentals of seismic velocity estimation and be able to recognize limitations and pitfalls in practical applications. This lecture is designed to provide insights into how seismic velocity estimation really works, what you can resolve, and what you will have difficulty resolving. I will present experiments that demonstrate the power and limitations of tomographic approaches that rely on iterative prestack migration. During this discussion you will learn concepts that might at first seem counter-intuitive; for example, lateral resolution of velocity anomalies can often be higher than vertical resolution. I will demonstrate simple and effective ways of performing analysis and quality control during velocity model construction. Finally, we will discuss emerging and advanced methods for building velocity models in the most complex settings that are currently of industrial interest.
The Virgil Kauffman Gold Medal is awarded to Carl Regone and John Etgen for their work in demonstrating the value of wide-azimuth towed-streamer acquisition for deepwater subsalt imaging, and for their role in bringing it to commercial reality. Through tireless efforts involving wave-equation modeling and evaluation of different approaches to acquisition, they convinced BP of the value of such acquisition, leading BP to embark upon a commercial program of wide-azimuth acquisition. The success of these efforts has led the industry into a new era of acquisition and imaging based upon the wide-azimuth technique. This technology is spreading outside the Gulf of Mexico and creating value for the industry around the world.
Biography Citation for the SEG Virgil Kauffman Gold Medal Award
Contributed by Michelle Judson
John and Carl’s recent extraordinary contributions to deepwater subsalt imaging are well known. They each bring their unique technical skills and talents to solving imaging problems. This latest success is just a part of their long joint tradition of combining the theoretical and the practical to discover commercially viable solutions. John and Carl’s partnership formed 15 years ago, the day a young research scientist (John) joined Amoco’s research center straight from university and started work on Carl’s R&D team. That partnership started the evolution of a powerful seismic modeling capability, which was one key enabler of their achievements.
John’s skill at creating new algorithms is legendary. He has a deep appreciation of the elegance of mathematical theories, but he couples this with a ready willingness to accept “inelegant” numerical approximations if they prove to be a more practical way of getting results. He pays close attention to current technical developments (he is an associate editor of GEOPHYSICS) and has a deep understanding of what the industry is doing, and which technologies are working out and which aren’t. He communicates constantly, happily building on ideas of others (immediately trying out any promising new ones he finds) and is also very willing to share his ideas to help others. He is always ready to immediately integrate a better way of accomplishing something into his programming “edifice.”
Carl has been attacking the seismic signal-to-noise problem throughout his career. He learned about arrays by designing missile targeting systems and brought this understanding into the seismic industry. A unique element of Carl’s inquiry was the desire to understand what acquisition was required to accurately measure and sufficiently understand noise. This led him to design experiments early on in his career to accurately record the entire wavefield, enabling evaluation of the critical elements of the recording geometry. He then imported that field experience into the lab… which for him is seismic modeling! This use of modeling and a deep understanding of field surveys enabled him to learn fundamental elements of seismic acquisition that could enhance subsalt illumination. Carl has a rare talent that blends innovation, technology development, and pragmatic solutions.
For a long time, industry had known that different acquisition azimuths illuminate different parts of the subsurface. The required breakthrough to take advantage of this knowledge was finding a cost-effective, practical solution to adding more azimuths. The magic that John and Carl have created is the ability to use forward modeling and imaging to solve problems in a technically sound and affordable way. Their combined skills enabled them to create strikingly ambitious models which they systematically used to simulate various acquisition and processing strategies. Having found a potential solution, their gift of effective communication allows them to cleanly explain to others the potential value of a technology for addressing business needs.
A key success factor in BP committing to spend the significant funds required to execute concurrent field trials of both wide-azimuth towed streamers and OBS nodes technologies was cutting the costs. Proving that less expensive acquisition configurations could provide adequate illumination was critical to the projects moving forward. Cost is always a bounding factor in research and development. A key tool in their repertoire is the trick of how to make a computer model that is just good enough. This is as much art as it is science. Carl and John are experts at knowing just how accurate a model needs to be to capture the essence of a problem without requiring any more computational expense and time than are necessary.
They also have a knack for knowing the right questions to ask, and just as important, they don’t assume they know the answers beforehand. This willingness to try things out and to adjust your theories based on what you observe is the very essence of the scientific method and a key ingredient of their success. They were able to ask the right questions, avoid dogmatic attachment to their preferred solutions, and conduct a landmark study that pushed the limits of computer modeling to try out various acquisition strategies.
Carl and John easily work with each other, enabling them to multiply their contributions. They also give unselfishly of themselves, their time, and their ideas to colleagues and the wider geophysical community. By so doing they are a catalyst for others, their ideas a basis for others to build on. They beautifully mix scientific rigor with real-world pragmatism, and have FUN while doing it.
If I have seen further, it is by standing on the shoulders of giants.
- Gray, S. H., et al. (2001 Seismic migration problems and solutions, GEOPHYSICS 66(5):1622.