TIME: Almanac 1993/TIME Almanac 1993.iso/time/121790/1217310.000

Text File | 1992-08-28 | 7.1 KB | 135 lines

                                                                                TECHNOLOGY, Page 98

Exploring the Ocean's Frontiers


Robots and miniature submarines take oil drillers to new depths

By Richard Woodbury


    The dark and forbidding depths of the Gulf of Mexico, once
frequented by only the hardiest of sea creatures, are now alive
with human activity. Miniature submarines and robot-like vehicles
prowl the ocean bottom while divers wend their way around
incredible underwater structures -- taller than Manhattan
skyscrapers but almost totally beneath the surface of the waves.
This is the new geological frontier, and a daring breed of
modern-day explorers is using technology worthy of Jules Verne
and Jacques Cousteau to find fresh supplies of oil and natural
gas.

    Until recently, drilling in the Gulf was concentrated close
to shore in water as shallow as 9 m (30 ft.). But now that most
of those easy-to-tap reserves are depleted, oilmen are looking to
the slopes of the continental shelf, hundreds of meters deep and
160 km (100 miles) or more from land. The cutoff of oil supplies
from Kuwait and Iraq and the resulting run-up in prices have lent
new urgency to the exploration ventures, some of which have been
in the works for a few years. "Oil at $30 to $40 a barrel is
suddenly making every project that boosts our domestic supplies
look a lot more feasible," says Wayne Dunlap, an off-shore
technology expert at Texas A&M.

    Led by Conoco, Occidental, Texaco and Shell, every major
international oil company has joined the hunt, which has turned
the blue-green waters off the coast of Louisiana and Texas into
one of the busiest exploration areas in North America. Even
Petrobras, the national oil company of Brazil and a deep-drilling
pioneer, has established a Houston-based subsidiary to get in on
the action. The lure of the Gulf is irresistible: estimated oil
reserves of up to 36 billion bbl., nearly four times as much as
in Alaska's Prudhoe Bay. Companies have snapped up nearly 1,700
federal drilling leases at depths of 370 m (1,200 ft.) and
beyond. Some 25 rigs are currently in operation, and several big
production projects are in the works.

    The far reaches of the Gulf are especially attractive to the
major companies because there has been little of the
environmental opposition that has blocked most drilling efforts
off California and the East Coast. The oil industry is a major
employer along the Gulf, and coastal residents have lived with
drilling just offshore since 1947.

    The deepwater quest began in 1984, when the Hunt brothers
pioneered some of the new production techniques in a subterranean
formation known as Green Canyon, some 240 km (150 miles)
southwest of New Orleans. But they failed to make the big strike
they needed to salvage their collapsing financial empire. Conoco
followed the Hunts and had more luck, finding sizable deposits at
the 535-m (1,760-ft.) level. The company, with Occidental and
Texaco, spent $400 million to build the world's deepest
production platform, and has been producing from 20 wells for
about a year.

    An equally huge project is Shell's $500 million Bullwinkle
platform, 130 km (80 miles) off the Louisiana coast. Standing 162
stories high -- taller by 49 m (161 ft.) than Chicago's Sears
Tower -- it looms like a gigantic iceberg in 412 m (1,353 ft.) of
water, only its top-deck production facilities visible above the
water. Chevron is planning a big project nearby. Southeast of New
Orleans, Exxon is operating a 110-story platform, and a few miles
away British Petroleum is erecting its own 100-story behemoth.

    Finding gas and oil deposits at such depths is no easy
technological feat. Seismologists in surface vessels bounce
sonar-like signals off the bottom, and computers use the echoes
to make three-dimensional tracings of rock formations likely to
contain oil. To get at the deposits, explorers must lower a drill
to the sea floor and then bore a hole 3 km (2 miles) or deeper
through sands and shales. The gear has to be specially
strengthened to withstand the high pressure and covered with fine
metal screens to keep out sand. Drill-ship operators employ
satellites and celestial navigation to take up a position
precisely over the hole, and heavy thruster motors keep the
vessel hovering there, even in heavy seas, for days at a time.
Decks the size of football fields are needed to stack the
thousands of meters of unusually tough steel pipe used to sink
the shaft.

    Bringing the oil to the surface and then through a pipeline
to shore is an even more vexing challenge, requiring new
construction design and logistical savvy. To get Shell's
Bullwinkle platform into position took 12 tugboats and
construction of the world's largest barge -- an aircraft-carrier-
size hulk -- to haul it. But when the oil is at depths beyond 450
m (1,500 ft.), such fixed production facilities become too costly
and complicated, forcing engineers to build floating platforms.
Conoco's deepwater facility, called a tension-leg well platform,
is tethered to pilings on the sea bottom by flexible strands of
heavy, tubular steel.

    Because divers cannot routinely work at these depths, oilmen
have turned to mini-submarines and creations called ROVs
(remotely operated vehicles) to install and maintain their rigs
and platforms. An operator topside maneuvers aluminum ROVs by
flashing signals through an umbilical tether containing
fiberglass optical wire. TV cameras mounted on the ROVs send back
pictures to the surface. To twist and turn the clawlike arms,
technicians rotate pistol-grip levers, as in a video game. Says
John Huff, president of Oceaneering International, which operates
the vehicles: "ROVs have removed all the limits on how deep we
can explore."

    To keep costs and maintenance down, oil companies are
ingeniously simplifying project designs. Conoco is doing only
minimal processing of gas and oil at its new platform. Instead,
the crude is routed through pipes on the bottom to a processing
unit 16 km (10 miles) away in shallower waters. Exxon is
investing $500 million in an elaborate subsea production system
that will permit initial processing of gas from 22 wells directly
on the sea floor. The gas will then flow to a larger facility
atop an undersea mountain.

    The current projects are only the beginning. "The real
potential lies farther and deeper offshore," says Roger Abel,
Conoco's general manager for production engineering. "The big
easies have all been found." Shell is investing $1.3 billion to
build and install a tension-leg platform some 411 km (255 miles)
southeast of Houston that will retrieve oil from a world-record
depth of 872 m (2,860 ft.). Called Auger, the giant is scheduled
to begin producing from 32 wells in 1993. Shell has also drilled
an exploratory well at a 2,300-m (7,500-ft.) depth, and Mobil and
Chevron hold leases to search in 3,000 m (10,000 ft.) of water.
As long as oil prices make the gamble worthwhile, today's
explorers will apparently go to any depths to unleash the next
great undersea gusher.