Make no mistake, he is an expert.
Alistair R. Brown wrote the definitive book on 3-D seismic interpretation, soon going into its fifth edition. He will discuss 3-D seismic as the first-ever joint AAPG/Society of Exploration Geophysicists (SEG) Distinguished Lecturer.
Present at the creation, Brown interpreted the first 3-D seismic survey in the North Sea, possibly the first 3-D seismic interpretation ever. He has seen 3-D seismic develop from suspect beginnings to become the premier tool for prospect evaluation.
So how does he describe 3-D seismic today?
Underused, yet "too popular for its own good."
Poorly understood. Sometimes strained beyond its limits.
Too often badly grasped and hastily interpreted.
"It (3-D) is a basket of skills and techniques."
Explorationists of all kinds, including petroleum geologists, tend to shortchange the science and overlook the skill, according to Brown.
"They've heard of 3-D seismic," he said. "They've heard it's a good thing. And they want some of it.
"The computer technology we have today is a tool -- a wonderful tool, but not a skill. The skill is understanding geology through geophysical data."
Seismic interpretation takes time, which can become a scarce commodity in the exploration-engineering process, according to Brown.
"There's a tremendous rush," he continued. "As 3-D has moved more into the facets of business and into the production area, we are more and more entwined with our engineering brethren."
But Brown aims his message more directly at geologists -- especially those who expect 3-D data to do nothing more than enhance an existing geological model.
"They feel that the geophysical data has to be forced to fit into that model, rather than being allowed to change the model," he said. "A volume of 3-D seismic data can itself be so good, and so definitive, as to dictate the geological model."
Trust the Data
Those concerns are reflected in Brown's lecture, titled "Let the Data Speak to You, or How to Improve Your 3-D Seismic Interpretation."
His lecture points include:
- Geoscientists and engineers are working on 3-D data without adequate understanding of geophysical principles.
- Some 3-D data is strained beyond its limit by interpreters with unreasonable expectations.
- In 2-D interpretation, seismic data adds information to an existing model. In 3-D, the data should be allowed to modify geological concepts.
- Interpreters must correlate seismic to geology on character, not simply time, and be alert to phase distortion.
- Seismic attributes, though "wonderful," lack independence and should not be too much subject to statistics.
Above all else, Brown urges, "we must let the data speak to us, and try to believe it" -- even if that means letting the seismic interpretation define the geological model of a prospect or reservoir.
Value-enhanced 3-D seismic will be the wave of the future, he believes: "The advances are going to come in combining other technologies with 3-D." As an example, Brown cites the use of multicomponent geophones to produce "volumes of shear-wave data."
Instead of stacking, amplitude variations with offset (AVO) will be used in conjunction with 3-D data. "Today, 3-D AVO is already being done in small quantities," he observed.
The use of 4-D data in reservoir monitoring also will continue to develop, though he warned that 4-D can suffer from the same lack of understanding that hampers 3-D's effectiveness.
As a child in England, Brown did not long to be a geophysicist when he grew up. One reason for that, he noted, was that he had never heard of geophysics. And he heard little more of it during his student days at Oxford University.
"I went up to college 39 years ago, in 1960. At that time, geophysics wasn't an undergraduate course. And for a long time afterward, it wasn't an undergraduate course. So geophysics wasn't even an option," he explained.
Brown studied Physics, considering it a "classical subject" for a major at a time when one's first degree was seen as "not too vocational." After just three weeks at Oxford, he met the woman who would become his wife, Mary.
That moment may have started his path toward geophysics, because she was studying geography.
"She claims, with some validity," Brown said, "that's where the 'geo' came from" to add to the "physicist."
All In the Timing
Another life-defining moment occurred in 1966, when the couple decided to move to Australia. It was someplace new where they could establish themselves, Brown explained. And the move marked the beginnings of a career.
"That was the wide open spaces. That was the chance to do something new. I had the title 'geophysicist' from the time I stepped off the plane in Australia. It was the branch of physics where one's laboratory was the outdoors," he said.
After six years in Australia they returned to the United Kingdom, where Brown took a job with Geophysical Service, Inc.
"One of the interesting influences is that the North Sea had basically 'happened' while we were gone. Between 1966 and 1972 it had blossomed into an active area and there was abundant opportunity," he said.
Technology for seismic acquisition developed along with the growth of the North Sea industry. In 1975, Brown recalled, the advent of 3-D seismic was "announced to the world."
The two first 3-D surveys were taken in the North Sea and the Gulf of Mexico, at about the same time, he said. By chance, Brown ended up tackling interpretation of the North Sea seismic.
"I just happened to be at the right place at the right time, and was asked to interpret the first 3-D seismic survey," he said. "I was there right from the start of commercial application."
It occurred to him immediately that existing interpretation techniques were "totally inadequate" for understanding 3-D seismic. He also knew he'd walked into the fresh breeze of a very promising opportunity.
Not that 3-D stormed the industry, or even blew in at more than a whisper. "In the first few years it was very slow to be accepted. But every new technology is like that, really," Brown noted.
By 1978, Brown had relocated to Geophysical Service's Dallas office. The first edition of his book "Interpretation of Three-Dimensional Seismic Data (AAPG Memoir 42)" appeared in 1986, and the following year he became an independent consultant.
He's widely recognized for his work in teaching 3-D, which takes him around the world. "Mary and I travel a lot. Since our children are grown, we use my independence to get to interesting places," he said.
Recently the couple visited Finland, Norway, Denmark and Holland, then spent a month in England before returning to Dallas. Days later, Brown left for Argentina.
Last year Brown received SEG's Special Commendation Award for his work in developing and teaching 3-D methods. When he thinks about 3-D interpretation and geoscientists, he hopes for open minds.
"My advice is, 'Try to think about the data as geophysically as possible.' Don't impose too rigid a geologic structure," he said.
"Let the data speak to you, and don't disregard its message lightly."