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Odd Reservoir Off Louisiana Prods
Oil Experts to Seek a Deeper Meaning
By CHRISTOPHER COOPER
Staff Reporter of THE WALL STREET JOURNAL
HOUSTON -- Something mysterious is going on at Eugene Island 330.
Production at the oil field, deep in the Gulf of Mexico off the coast of
Louisiana, was supposed to have declined years ago. And for a while, it
behaved like any normal field: Following its 1973 discovery, Eugene Island
330's output peaked at about 15,000 barrels a day. By 1989, production
had slowed to about 4,000 barrels a day.
Then suddenly -- some say almost inexplicably -- Eugene Island's fortunes
reversed. The field, operated by PennzEnergy Co., is now producing
13,000 barrels a day, and probable reserves have rocketed to more than
400 million barrels from 60 million. Stranger still, scientists studying the
field say the crude coming out of the pipe is of a geological age quite
different from the oil that gushed 10 years ago.
Fill 'er Up
All of which has led some scientists to a radical theory: Eugene Island is
rapidly refilling itself, perhaps from some continuous source miles below
the Earth's surface. That, they say, raises the tantalizing possibility that oil
may not be the limited resource it is assumed to be.
"It kind of blew me away," says Jean Whelan, a geochemist and senior
researcher from the Woods Hole Oceanographic Institution in
Massachusetts. Connected to Woods Hole since 1973, Dr. Whelan says
she considered herself a traditional thinker until she encountered the
phenomenon in the Gulf of Mexico. Now, she says, "I believe there is a
huge system of oil just migrating" deep underground.
Conventional wisdom says the world's supply of oil is finite, and that it was
deposited in horizontal reservoirs near the surface in a process that took
millions of years. Since the economies of entire countries ride on the
fundamental notion that oil reserves are exhaustible, any contrary evidence
"would change the way people see the game, turn the world view upside
down," says Daniel Yergin, a petroleum futurist and industry consultant in
Cambridge, Mass. "Oil and renewable resource are not words that often
appear in the same sentence."
Mideast Mystery
Doomsayers to the contrary, the world contains far more recoverable oil
than was believed even 20 years ago. Between 1976 and 1996, estimated
global oil reserves grew 72%, to 1.04 trillion barrels. Much of that growth
came in the past 10 years, with the introduction of computers to the oil
patch, which made drilling for oil more predictable.
Still, most geologists are hard-pressed to explain why the world's greatest
oil pool, the Middle East, has more than doubled its reserves in the past 20
years, despite half a century of intense exploitation and relatively few new
discoveries. It would take a pretty big pile of dead dinosaurs and
prehistoric plants to account for the estimated 660 billion barrels of oil in
the region, notes Norman Hyne, a professor at the University of Tulsa in
Oklahoma. "Off-the-wall theories often turn out to be right," he says.
Even some of the most staid U.S. oil companies find the Eugene Island
discoveries intriguing. "These reservoirs are refilling with oil,"
acknowledges David Sibley, a Chevron Corp. geologist who has
monitored the work at Eugene Island.
Mr. Sibley cautions, however, that much research remains to be done on
the source of that oil. "At this point, it's not black and white. It's gray," he
says.
Although the world has been drilling for oil for generations, little is known
about the nature of the resource or the underground activities that led to its
creation. And because even conservative estimates say known oil reserves
will last 40 years or more, most big oil companies haven't concerned
themselves much with hunting for deep sources like the reservoirs scientists
believe may exist under Eugene Island.
Economics never hindered the theorists, however. One, Thomas Gold, a
respected astronomer and professor emeritus at Cornell University in
Ithaca, N.Y., has held for years that oil is actually a renewable, primordial
syrup continually manufactured by the Earth under ultrahot conditions and
tremendous pressures. As this substance migrates toward the surface, it is
attacked by bacteria, making it appear to have an organic origin dating
back to the dinosaurs, he says.
While many scientists discount Prof. Gold's theory as unproved, "it made a
believer out of me," says Robert Hefner, chairman of Seven Seas
Petroleum Inc., a Houston firm that specializes in ultradeep drilling and has
worked with the professor on his experiments. Seven Seas continues to
use "conventional" methods in seeking reserves, though the halls of the
company often ring with dissent. "My boss and I yell at each other all the
time about these theories," says Russ Cunningham, a geologist and
exploration manager for Seven Seas who isn't sold on Prof. Gold's ideas.
Energy Vacuum
Knowing that clever theories don't fill the gas tank, Roger Anderson, an
oceanographer and executive director of Columbia University's Energy
Research Center in New York, proposed studying the behavior of oil in a
reservoir in hopes of finding a new way to help companies vacuum up
what their drilling was leaving behind.
He focused on Eugene Island, a kidney-shaped subsurface mountain that
slopes steeply into the Gulf depths. About 80 miles off the Louisiana coast,
the underwater landscape surrounding Eugene Island is otherworldly, cut
with deep fissures and faults that spontaneously belch gas and oil. In 1985,
as he stood on the deck of a shrimp boat towing an oil-sniffing contraption
through the area, Dr. Anderson pondered Eugene Island's strange history.
"Migrating oil and anomalous production. I sort of linked the two ideas
together," he says.
Five years later, the U.S. Department of Energy ponied up $10 million to
investigate the Eugene Island geologic formation, and especially the oddly
behaving field at its crest. A consortium of companies leasing chunks of the
formation, including such giants as Chevron, Exxon Corp. and Texaco
Corp., matched the federal grant.
Time and Space
The Eugene Island researchers began their investigation about the same
time that 3-D seismic technology was introduced to the oil business,
allowing geologists to see promising reservoirs as a cavern in the ground
rather than as a line on a piece of paper.
Taking the technology one step further, Dr. Anderson used a powerful
computer to stack 3-D images of Eugene Island on top of one another.
That resulted in a 4-D image, showing not only the reservoir in three spatial
dimensions, but showing also the movement of its contents over time as
PennzEnergy siphoned out oil.
What Dr. Anderson noticed as he played his time-lapse model was how
much oil PennzEnergy had missed over the years. The remaining crude,
surrounded by water and wobbling like giant globs of Jell-O in the
computer model, gave PennzEnergy new targets as it reworked Eugene
Island.
What captivated scientists, though, was a deep fault in the bottom corner
of the computer scan that was gushing oil like a garden hose. "We could
see the stream," Dr. Anderson says. "It wasn't even debated that it was
happening."
Woods Hole's Dr. Whelan, invited by Dr. Anderson to join the Eugene
Island investigation, postulated that superheated methane gas -- a
compound that is able to absorb vast amounts of oil -- was carrying crude
from a deep source below. The age of the crude pushed through the
stream, and its hotter temperature helped support that theory. The
scientists decided to drill into the fault.
Unlucky Strike
As prospectors, the scientists were fairly lucky. As researchers they
weren't. The first well they drilled hit natural gas, a pocket so pressurized
"that it scared us," Dr. Anderson says; that well is still producing. The
second stab, however, collapsed the fault. "Some oil flowed. I have 15
gallons of it in my closet," Dr. Anderson says. But it wasn't successful
enough to advance Dr. Whelan's theory.
A third well was drilled at a spot on an adjacent lease, where the fault
disappeared from seismic view. The researchers missed the stream but hit
a fair-size reservoir, one that is still producing.
It was here, in 1995, that the scientists ran out of grant money and
PennzEnergy lost interest in continuing. "I'm not discounting the possibility
that there is oil moving into these reservoirs," says William Van Wie, a
PennzEnergy senior vice president. "I question only the rate."
Dr. Whelan hasn't lost interest, however, and is seeking to investigate
further the mysterious vents and seeps. While industry geologists have
generally assumed such eruptions are merely cracks in a shallow oil
reservoir, they aren't sure. Noting that many of the seeps are occurring in
deep water, rather than in the relative shallows of the continental shelf, Dr.
Whelan wonders if they may link a deeper source.
This summer, a tiny submarine chartered by a Louisiana State University
researcher will attempt to install a series of measuring devices on vents
near the Eugene Island property. Dr. Whelan hopes this will give her some
idea of how quickly Eugene Island is refilling. "We need to know if we're
talking years or if we're talking hundreds of thousands of years," she says.
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