Deep Sea Roughnecks
Kerr-McGee Corp. made petroleum history in 1947 by drilling 10 miles off the Louisiana coast. Although its Kermac 16 was a milestone in offshore drilling technology, the water was only 20 feet deep.
However, unlike the Gulf of Mexico with its continental shelf, the West Coast gets very deep, very quickly. Drilling in depths of 200 feet and beyond – now common in the Gulf – once required the endurance and capabilities of experienced hard-hat divers.
Albacore divers found new opportunities when petroleum exploration began off the California coast near Santa Barbara.
In 1948, Shell Oil Company joined Continental Oil (today’s Conoco-Phillips), Union Oil and Superior Oil in a joint venture – the CUSS Group.
“With leasing from the state of California to explore and produce oil and gas, well control and the ability to run multiple strings of casing became mandatory and required a totally new, unproven technology,” explains the Society of Petroleum Engineers (SPE).
“The first floating drilling rig to use subsea well control was the Western Explorer owned by Chevron, which spudded its first well in 1955 in the Santa Barbara Channel,” the society adds. Other offshore rigs – and innovations – soon followed. Engineers, concerned about the marine environment, developed technologies to allow drilling in rough weather.
The CUSS (Continental, Union, Shell, Superior Oil) objective was to pursue deepwater drilling – and for the first time develop motion-restricted drilling ships. The first conversion effort was the Submarex, a converted U.S. Navy submarine chaser.
Submarex was followed in 1956 by the CUSS I, which used four steering propellers and six mooring buoys to hold the ship in position. The vessel, built from a World War II barge, was 260 feet long and had a 48 -foot beam.
A 95-foot derrick sat amidships over a diamond shaped opening, which is still known today as a “moon pool.”
During this same period, the U.S. Navy was developing its own deep-sea technology for both submarine rescue and Cold War antisubmarine purposes. Tethered to a mother ship by long umbilical cables, remotely operated underwater vehicles (ROV) helped find the the nuclear attack submarine USS Thresher, which sank with all hands in 1963.
CUSS I pioneered the use of underwater television cameras to assist in survey, inspection and repair work. In 1965, the vessel drilled a well in 635 feet of water, setting and cementing multiple strings of casing without using divers. But most offshore petroleum work still required traditional hard-hat divers.
Reaching New Depths
The pursuit of offshore oil inevitably demanded technological innovation as exploration led to deeper and more inhospitable waters.
Offshore divers faced new challenges, including one hazard called “stabbing in.”
“Because re-inserting a drill pipe from a moving, heaving barge into the subsea wellhead was a difficult maneuver, each time a worn drill bit had to be replaced, a diver had to be called,” notes Underwater magazine in a May 2000 article.
“The hard-hat diver effected the ‘stab-in’ by straddling the top of the 24-inch hole between his legs, physically pulling the drill string over the target and at just the right moment instructing the drill floor, 250 feet overhead, to ‘let go.’”
Modern technology spares divers this dangerous task, notes Christopher Swann, author of The History of Oilfield Diving, 2007. Instead of air, divers began breathing mixtures of helium and oxygen during deep descents and carefully managed decompression ascents.
Saturation diving and decompression chambers were developed to further increase bottom times and improve safety. With deep saturation diving, every 100 feet of depth required 24 hours of decompression and like today, time was money.
The extreme cold of deep water prompted Taylor Diving & Salvage of Belle Chasse, Louisiana, to adapt space suits designed for Nasa astronaut John Glenn to deep sea diving. Hot water pumped down from the surface and through dive-suit tubing extended bottom times.
Taylor also developed an underwater welding habitat pressurized with nitrogen that greatly facilitated the critical business of laying pipeline, tie-ins and repairs.
Even with state-of-the-art robotics, offshore petroleum industry and scientific needs for manned deep sea diving continue. Atmospheric Diving Systems enclose the operator at one-atmosphere pressure, regardless of depth, thereby eliminating the necessity for decompression.
Today, the “Hardsuit 2000” with 16 rotary joints and two thrusters for mobility, bears little resemblance to its traditional hard-hat ancestors. The suit can operate at depths up to 2,000 feet and remain for six hours on the bottom with no decompression required.
Pursuit of offshore oil and natural gas continues to generate new technologies just as it has in the past. Innovators and underwater roughnecks will continue to push both science and industry to new and deeper frontiers.
More than 4,500 offshore petroleum platforms supply 25 percent of the United States’ production of natural gas and 10 percent of its oil. An industry-government partnership use offshore structures no longer producing to form the world’s largest artificial reef complex.
See also Offshore Petroleum History.
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