John Sherwood

John Sherwood

Membership	Honorary Membership

SEG Maurice Ewing Medal 2008

John Sherwood, the 2008 recipient of SEG’s highest award, the Maurice Ewing Medal, has previously been honored by the Society with the 1986 Virgil Kauffman Gold Medal award (exploding reflector concept and DMO), Honorary Membership in 1993, the 2004 Cecil Green Enterprise Award (for co-founding GDC), and selection as a Distinguished Lecturer in 1989 (robust linear inversion and tomography).

In his early career, John developed analog modeling, robust static solutions, minimum wave propagation theory, spectrum balancing (dereverberation), and early digital migration. From 1970 to 1981, he developed DEVILISH (first DMO implementation), pre- and poststack depth migration algorithms, improvements in time migration, REVEAL (layer replacement for complex overburden), and DIGISTACK (noise suppression with coherency). In 1975, John’s migration patent was defended before the Supreme Court. He co-founded GDC in 1981 and, from then until 1998, his contributions included SOLID (refl ectivity modeling), improved velocity analyses, migration, statics, and near-surface 2D tomography which is the basis of major commercial tomography implementations. John has led technical program committees for SEG and OTC, has been GEOPHYSICS Associate Editor, and a mentor of PhD students.

After joining Applied Geophysical Services in 1998, John, who now serves as president, personally funded, directed, and developed a new technology for prestack depth migration. Drawing on his innovative 2D beam-migration approach that dated from his Chevron days, John had a prototype ready within a year. The 3D version quickly followed, with additional tools to suppress coherent noise using dip, azimuth, frequency, and amplitude. This technical approach of imaging has been widely accepted by the industry as validated by the recent sale of John’s AGS technology for US$61 million to PGS. John is continuing to add capabilities for enhanced seismic data processing and imaging with unique processes such as multi-azimuth, multi-off set tomography using beam migration, and 3D residual normal moveout (RNMO). In short, within the past ten years, John has once again produced technical advancements to exploration geophysics that match his previous work which had earned important SEG awards. John has made, several times over, contributions that warrant the Maurice Ewing Medal. His unique management style, reputation, and generosity have also contributed to the technical successes of others throughout his career.

Biography Citation for the Maurice Ewing Medal

Contributed by Fred Hilterman

Renaissance man is a term that certainly describes our Maurice Ewing Medalist, John W. C. Sherwood, as is evident by the accomplishments and honors outlined in the above preamble from the SEG Honors and Awards Committee. The total significance of John’s geophysical contributions is difficult to enumerate because many of his research efforts have been the inspiration that other scientists have built upon. And after nearly a half-century, his work continues to influence the direction exploration geophysics is taking, especially in building a better image of the Earth.

At Imperial College in the mid-1950s, John developed theoretical and physical models relating to Lamb’s problem. Afterwards he spent two years with the National Research Council of Canada and then joined the California Research Corporation (Chevron). Fred Herkenhoff , a colleague at Chevron, noted at a recent symposium honoring John that “Sherwood took advantage of the switch from analogue to digits to extend concepts in deconvolution, near-surface corrections (statics), velocity estimation, multiple attenuation, migration, and the integration of migration with signal enhancement.” These early days at Chevron were ripe for innovation, and John, Alan Trorey, and other colleagues met the challenge. They became fascinated with an imaging concept that was promoted by Frank Rieber in 1937 as they saw it as a means to develop a fast and accurate migration program on the primitive computer systems to the time. While many geophysicists were skeptical of Rieber’s earlier theory, John took full advantage of Rieber’s dip-scan to define seismic events.

An interesting side note is that both John and Maurice Ewing were supporters of Rieber’s research.

In the early 1970s, John became director of research at Digicon. Quickly John placed his indelible mark on Digicon by producing, as part of his research effort, prestack time and depth migrations which led to “partial migration before stack,” which he named “DEVILISH,” a method we commonly call DMO. In 1981, John became an entrepreneur as a cofounder of Geophysical Development Corporation (GDC) where he also served as Vice President of research. Once again, this Renaissance man astounded industry with his prodigious output of a multitude of different research products. His perseverance for perfection and detail is uncanny. I remember that, after he finished developing the software product SOLID (a reflectivity modeling program), he was asked the cost of the yearly maintenance. His reply was, “Nothing, the code is correct.” And that’s right, not a correction needed in 25 years. Similarly, a few years later, John astonished his colleagues when his tomographic technique dramatically demonstrated the accuracy requirements in fi eld surveying necessary for seismic depth conversion.

After the sale of GDC to Geokinetics, John continued his entrepreneurial adventures by joining AGS in 1998 and proceeding to personally fund and lead the algorithm and software development of an innovative beam imaging system.

John’s work at AGS has definitely been a technical and fi nancial success, as once again, John set a technical standard for our industry.

It was John’s unselfishness and professionalism that contributed greatly to Chevron, Digicon, GDC, and AGS gaining reputations as leading companies in technological innovation. Throughout his career, John maintained his personal pursuits with stock and business ventures. He continues to enjoy the historical West African art collected and researched by his wife Edith, a biomedical scientist with a PhD in chemistry. The Sherwoods’ pride and joy are their three children, who are distinguishing themselves in the fields of medicine, computer science, and geophysics. Of course, many of us are aware of the numerous contributions that his son Kevin, who works closely with John at AGS, has already made for the geophysical industry and SEG. Few individuals have made as many major contributions to the advancement of geophysics as John. I am proud to summarize a few of his scientific accomplishments, to provide a few words about his personal successes, and to be part of the event at which SEG bestows the Maurice Ewing Medal on

Cecil Green Enterprise Award 2004

Contributed by Richard Verm

A successful company by some definition must be greater than the sum of its parts. Truly that was the case for Geophysical Development Corporation. The combination of Fred J. Hilterman, Reg Neale, and John W.C. Sherwood brought together a collection of skills and attitudes that made GDC into a respected, successful company. John W.C. Sherwood provided the technology arm of GDC. Long before the start of GDC, John had made significant contributions in the area of seismic imaging.

Sherwood studied at the Imperial College of London, Department of Physics, where he received BSc, ARCS, DIC, and PhD degrees. After two years with the National Research Council of Canada, he began his professional career at Chevron as a geophysical researcher. One of John's notable accomplishments was the award of a patent in 1975 for a digital seismic migration technique. From Chevron, John went to Digicon as vice president of research. It was there that he developed perhaps his most famous imaging concept "partial migration before stack", DMO, (or as he called it Devilish). In addition, John published several papers with respect to both time and depth migration. With his fame and professional career well established, John made the jump with his two co-founders to start a new company, GDC. This, to leave a secure position and build a company from scratch, best exemplifies his spirit of entrepreneurship and daring but he and his co-founders accomplished this and more.

After the formation of GDC, John continued to contribute and publish in the area of seismic imaging with papers on time and depth migration. One of his first tasks at GDC was to transform his 1958 PhD dissertation on elastic wave propagation and write the highly successful modeling program SOLID. SOLID was, and continues to be, a highly effective tool in the analysis of seismic AVO. This was only the beginning in a long line of works in migration, statics, noise reduction, and velocity analysis that John implemented at GDC.

Based on John's work and technical capabilities, GDC entered into a long-term research contract with Saudi Aramco. During this relationship, John developed many of the algorithms for statics and near-surface tomography that became part of the GDC production base.

Always a tireless worker, John also found time to contribute to SEG. He served as an associate editor of GEOPHYSICS on several occasions including Associate Editor for Tomography and Seismic Wave Propagation in 1985. His efforts did not go unnoticed. John was honored by SEG with the Virgil Kauffman Gold Medal in 1986 for his work on DMO. SEG Honorary Membership was awarded in 1993 and he was selected as the SEG's Distinguished Lecturer for the spring of 1989. It was John's unselfishness and professionalism that contributed greatly to GDC's reputation as a leading company in technology.

Throughout his time at GDC, John maintained his personal pursuits with stock and business ventures. He continues to enjoy the historical West African art collected and researched by his wife Edith, a biomedical scientist with a PhD in chemistry. In addition, he and Edith managed to raise three children who are distinguishing themselves in the fields of medicine and business. In the end, John's personal integrity, professionalism and enthusiasm became an integral part of the success of his company.

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