Point of View — New SEG chief: Geomechanics enhancing interdisciplinary work

Steady progress in petroleum geophysical methods enhances interdisciplinary asset management, a work pattern central to the modern upstream oil and gas industry.

The progress, says the incoming Society of Exploration Geophysicists president, comes from growing attention to geomechanics around the wellbore.

“In some circles we’re still trying to learn each others’ languages and understand each others’ tools,” says T.K. (Terry) Young, professor and head of the Department of Geophysics at Colorado School of Mines. “In other circles we’re finding geoscientists and engineers speaking to each other and working intimately together. Maybe this area of geomechanics is a magnet pulling us closer together.”

Young, who will assume the SEG presidency at the end of the association’s annual meeting this week, says improvement in geophysical methods comes from increasingly sophisticated application of the wave equation, which models propagation of seismic energy through the subsurface.

“At one time we found a lot of hydrocarbons treating the earth as a fluid basically, using compressional wave data,” he explains. “We had a simple representation of the physics of the earth and were quite successful.”

More recently, geophysical techniques, bolstered by computer improvements, have become able to extract more and more information from seismic reflection data and better able to deal with the plasticity and complexity of the subsurface. For example, processing once combined-or stacked-data to enhance the reflection signal and reduce data loads. Now, much processing is performed before stack, enabling interpreters to make use of information formerly lost in processing.

The burgeoning computing power that has enabled geophysicists to process and interpret prestack data promptly also helps them deal with the increasing complexity of their results through advanced imaging and visualization techniques. Hence the movement Young cites toward geomechanics: “having enough information to have a handle on the whole stress field around a well.”

Improvement like this takes time.

“We’ve often been poised and waiting with the physics and know-how, waiting for the volumes of data and the problem to drive that technology to appear,” Young says.

Physics and sampling

An example, he adds, is a computationally intense technique known as prestack depth migration. Geophysicists had mastered the concepts and mathematics long before they had either computers able to handle the enormous data volumes involved or a practical problem needing a solution. The problem turned out to be the need to create images of sedimentary strata below salt formations in the Gulf of Mexico.

Geophysical progress thus involves “more and more precise mathematical representations of our physics and more dense sampling of our fields or of our exploration targets,” Young says. Seismic surveys use growing numbers of sensors with growing numbers of components and thus are able to acquire “richer and richer samples of the seismic wave field.”

As a result, geophysicists are increasingly able to estimate components of subsurface stress and strain “that give out a more complete characterization of a fractured reservoir.” Progress in this area, Young says, moves the industry toward “the intersection of geophysics and reservoir characterization” and toward convergence of the disciplines of geophysics, geology, and petroleum engineering.

An important seismic technique that has developed during this evolution is multicomponent recording, which yields data on transverse vibrating energy-or shear waves-as well as compressional waves. And an important seismic application that has emerged is the 4D seismic survey, really a series of 3D surveys over a producing field conducted to monitor reservoir changes over time.

Techniques like these have produced a “shift in exploration geophysics to development and production geophysics,” Young says. “The question is whether that trend will continue and whether we’ll go back to serious exploration.”

Trends in academia

In academia, the interdisciplinary approach is well-established in both teaching strategies and student interest, Young says, noting, “We have students who are geophysics PhD candidates doing reservoir simulation.”

Evening sessions he and a colleague recently conducted on the various disciplines “nearly packed the lecture hall four nights running,” he says.

Part of the reason for the interest is that companies recruiting geoscientists seek graduates with an integrated perspective on the other disciplines, at least at the undergraduate and master’s degree level. “At the PhD level,” Young says, “there’s still a desire to hire an extraordinary scientist.”

Lately, he adds, recruitment has been “just a frenzy.” Students receive four or five offers apiece just for internships, and salary offers for full-time positions have become “quite high.”

The recruitment binge follows a period in which the oil and gas industry fretted about a “great crew change” but didn’t prepare for it with steady hiring or support for university programs, Young says.

“There hasn’t been an attempt to solve the problem until the problem is here, and all of a sudden there’s a huge recruitment effort,” Young says.

So top geoscience and engineering schools like Colorado School of Mines must balance the need to expand to meet industry requirements against the need to preserve quality. Mines will allow enrollment to grow, Young adds, but not without limits.

Asked about the type of graduate industry seeks from academia, Young says, “A good quantitative person with good analytical skills.”

In the last 5 years, he adds, hiring companies have shown “a strong preference for students who have done an internship, preferably with them.”

Young voiced his concern about the industry’s extreme employment swings in a presentation on “blended learning” at a recent workshop. Describing his subject as “capturing the intellectual capital, the know-how, the wisdom of the mature geoscientists and engineers and conveying it to younger workers,” he warns: “In some circles we will have to rediscover and reinvent some things because of experience lost, know-how lost through the cracks.”

Research lapse

Like many scientists and technical specialists affiliated with the oil and gas industry, Young worries about diminishing levels of research and development conducted by companies.

“The analysts on Wall Street seem to have taken over the decision process in a lot of the boardrooms in the last couple of decades,” orienting decisions to the next quarterly financial report.

“Real research doesn’t get a chance in a lot of quarters now,” says Young, who held research positions with Mobil Corp. before joining the university in 2000. He lists his own current research interests as statistical applications in geophysics; stochastic modeling, prediction, and forecasting; statistical pattern recognition; digital image processing and analysis; and avalanches.

The migration of industry research toward service companies and away from operating companies also creates problems.

“If we have research going on in part of the network, in the university or in the university and the service company but not in the oil company, then we don’t have people who can speak the language,” he says. The lapse “retards the progress, the rate at which new technology is embraced and employed in the industry.”

SEG’s priority

Young speaks of the professional society he will lead for a year as a tool for addressing the hazards growing out of a period of uneven professional hiring and curtailed research.

He says a priority for SEG is “to capture and disseminate, communicate cutting-edge geophysical know-how” across a membership growing fastest in its youngest age groups. More than half of SEG’s members live outside North America, he adds.

In keeping with the interdisciplinary trends of industry and academia, the group increasingly conducts events with other professional groups such as the Society of Petroleum Engineers and American Association of Petroleum Geologists. SEG and AAPG, in fact, are discussing a joint annual meeting.

Young expects most teamwork among professional societies to coalesce around “themes that need addressing” and says collaboration will reach beyond industry bounds.

“There’s a real interest in the scientific community in the humanitarian applications of what we know,” he says. “The grand-challenge problems are multidisciplinary in nature.”✦

Career highlights

T.K. (Terry) Young is professor and head of the Department of Geophysics at Colorado School of Mines, Golden, Colo.

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