Petrophysicists and geophysicists meet to discuss integration, and the lack thereof, between their disciplines.
Here's a little teaser for our August issue. In that issue will be the results of a round-table discussion I held recently that invited petrophysicists and geophysicists to talk about some of the problems they're encountering in attempting to work together on projects and what can be done to solve them. I won't divulge all of those secrets now, but since I have more information than I can cram into a two-page article next month, I thought I might examine some of it this month.
The past is always a key to the present, and in this case, based on the total lack of integration between the two sets of physicists in the past, it's no wonder they're still having some issues.
"Petrophysical/geophysical integration has come a long way, but I still think it has a long way to go," said David Eickhoff, advanced senior petrophysicist for Marathon Oil's exploration services, worldwide exploration. "When I came into the industry in 1982, the petrophysicists were on one floor, and the geophysicists were on another. Oftentimes we didn't meet the geophysicists until the prespud meeting."
Since then the physical barriers have been broken down, but other barriers remain, Eickhoff said. "I've found that petrophysicists are still doing their traditional work, which has been pay counting, porosity, water saturation and volumetric work. Even with the move to multidisciplinary teams, a lot of them still fall back on that sort of work."
Some of it might be training. Bob Truman, senior director of marketing at Baker Atlas, said that while geophysicists have a number of excellent university programs to choose from and can work under the tutelage of well-known professors, petrophysicists don't have as many degree programs that cater specifically to that discipline. Indeed, most of the petrophysicists that attended my meeting had degrees in either geology or mechanical engineering.
"When you look at petrophysicists, most are industry-trained by different service companies or oil companies, all with their own philosophy," Truman said. "So you're not really sure what you're getting."
Eickhoff added that generally petrophysics training at the university level is handled through a petroleum engineering program, so the emphasis is on formation evaluation with little mention of geology or geophysics. "If the formation evaluation classes were taught more as a geoscience as opposed to an engineering type of discipline, that would help," he said.
In the past this has caused huge problems within both disciplines, and some of the largest gaffes occurred in the 1980s when amplitude variations with offset (AVO) processing first arrived on the scene. At least some vague understanding of rock physics is required to do AVO properly. But Peter Duncan, chief operating officer of Chroma Energy, said that the "bright spot" mentality got so many people excited that they often forgot to question the underlying science.
"In the early '80s I had the opportunity to study all sorts of anomaly maps, and there would be pretty red spots," he said. "I'd ask, 'Do you have the right to expect there to be an anomaly here?' And they'd look at me quizzically.
"But I think the appreciation of that has come a long way in the past 20 years."
Still, even those petrophysicists who want to work on the rock physics problems might find limited use for their skills in the real world.
Tad Smith, manager of petrophysics at Veritas DGC, has spent years honing his skills to be proficient at integrating petrophysical and geophysical data. But sometimes the geophysicists don't seem to be interested in the additional information he can bring to the project.
"They like the sort of modeling work I do with the petrophysics," he said. "But at the end of the day they really want my edited logs and my shear velocity information. They'll do the rest."
Many of the participants blamed time pressures. Allen Bertagne, head of PGS Reservoir Consultants US, said the demands on geophysicists to make the right decisions quickly can counter any inclination they might have to spend more time on the modeling.
"If I'm a geophysicist working on a lease sale, I've got all of this data that I need to interpret, and I'll say, 'Quick, give me that shear wave curve, give me those logs, we'll cram them in the workstation,' and if I work until midnight enough times I might have this ready for the sale," he said. "I'm not sure there's any agenda present, but what Tad describes does occur."
The general consensus is that both disciplines need to focus more heavily on rock properties, which are, after all, what cause many of those squiggly lines on seismic traces and well logs.
"To me, if someone says petrophysics, they're talking pay count," Duncan said. "If they say rock physics, they're talking about that higher-order discipline that is, generally speaking, the realm of the enlightened geophysicist or petrophysicist. Rock physics is where we actually start understanding the seismic signature of the rocks under different fluid, pressure and temperature conditions. And geophysicists are really trying to understand that stuff because they're beginning to realize that they have to have some justification for the anomalies that they see."
There's much, much more to report, including some potential solutions to the problem and a generally optimistic outlook for the future. I hope I've whetted your appetite. Meanwhile, I'd like your feedback on this topic, so feel free to e-mail me with your ideas.

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