AVO signatures come in all shapes and sizes, but and their impact can be significant.

Steve Rutherford has degrees in physics from Baylor University and a doctorate in Electrical Engineering from the University of Texas at Austin.

Almost 20 years ago, a paper appeared in Geophysics that would change the viewpoint of many geophysicists about the value of amplitude-versus-offset (AVO) analysis. The technology was deemed less than reliable when it came to finding large gas accumulations anywhere other than the Gulf of Mexico. The author, Steve Rutherford, demonstrated that, while AVO signatures differed based on local geology, they still brought something very important to the global exploration toolkit.

Today Rutherford is the director of direct detection technologies for Seismic Ventures, a company that helps independent oil and gas companies with their seismic processing and interpretation challenges. Since his foray into the oil and gas industry in 1980, he has become a recognized expert in AVO analysis.

Rutherford has degrees in physics from Baylor University and a doctorate in Electrical Engineering from the University of Texas at Austin, where he studied underwater acoustics. “The industry was crying out for people who knew about wave propagation,” he said. He joined Getty Research and worked there until the company was acquired by Texaco; then he then moved to Tenneco. In 1986, he was transferred to the geophysical research center. “I was able to experiment in specific technologies, AVO in particular,” he said. Before the technology had really gained a stronghold in the industry, Rutherford was tasked with implementing AVO analysis company-wide. “I was able to devote my time to developing tools, soliciting case studies, and working on AVO projects,” he said.

After Tenneco, Rutherford joined Anadarko, where he worked for the next 19 years. In addition to furthering industry understanding of AVO, he also worked in a corporate planning group that used economic theory based on stock portfolio optimization methodologies to improve asset management.

In his current position at Seismic Ventures, Rutherford provides clients with sophisticated AVO and prospect analysis as well as economic evaluation on their projects. E&P asked him what had changed about the science over the years.

“In some ways there have been huge changes, but in other ways no real change at all,” he said. “In the early days people were looking only for amplitudes that increased on the far offsets. Pre-stack seismic data then was very noisy compared to the processed data we can generate these days.

“Back then we would mostly hunt for AVO anomalies. If we didn't find any, we didn’t quite know why or what it meant.”

Today many more attributes have been brought into the picture, and they behave differently depending on the setting. “The early applications focused on one end of the spectrum, the classic Gulf of Mexico (GoM) bright spots,” he said. “But the AVO response can be of use in hard rock environments (AVO Class I) as well. The near- offset response for a Class I sand is a peak that eventually declines and turns into a trough as offset increases. It’s a very distinct signature that’s quite different from a Class III GoM AVO anomaly."

“We now understand the whole spectrum of responses, and it has impacted the way AVO is implemented,.” he added.

Currently Rutherford is spending most of his time supporting Seismic Ventures’ clients with his modeling, analysis and interpretation expertise,; however, more research continues to beckon. “I have a lot of ideas I’d like to pursue, and I’m working with the R&D team at Seismic Ventures to advance the technology” he said.