September 2007

Oil rigs move pumping downstairs

A shift in offshore oil rig automation and technology has pumps and other machines normally found topside, moving below the wave line to the ocean floor. 

The advantages of the strategy are lower costs and the ability to tap smaller reservoirs. As well, companies can squeeze more oil out of aging fields by adding pumps on the seabed, closer to the oil. 

Further, by going underwater the hardware is out of the way of hurricanes, cyclones, icebergs, and terrorists. 

The Wall Street Journal reported on Anadarko Petroleum Corp.’s Inde-pendence Hub platform, which sits in 9,000-ft deep water in the Gulf of Mexico.

The control room view is a computer screen with a spider web of wells, pipes, and flow lines used to extract natural gas, all of which are invisible from the platform because the wellheads, pumps, separators, and meters distinguishing most petroleum platforms sit on the ocean floor. The Independence Hub floats in the deepest water of any offshore platform. Plans call for the hub to suck up to 1 billion cubic feet of natural gas from the earth every day. By itself, the platform will produce enough gas to heat about 4.8 million U.S. homes.

Giant offshore platforms remain the Hollywood stars of the petroleum industry, appearing on covers of countless glossy annual reports. However, the industry is finding fewer fields large enough to justify building a massive structure loaded with drilling derricks and well controls atop the reservoir. This has opened the door for a distinctly less photogenic alternative: the subsea well.

Ten different gas fields are feeding into the Independence Hub, which is basically a floating pipeline hub, with an assortment of gas compressors. The remotest field, Cheyenne, is 30 miles south of the hub. Together, the fields hold an estimated 2 trillion cubic feet of discovered natural gas reserves. If it were a single field, it would be one of the largest in the prolific gulf.

The fields connect as a network using 125 miles of “umbilicals”—thick flexible tubes that send electricity, orders, and chemicals to the wells. It is so cold 9,000 feet below the waves that droplets of water in the gas can freeze and gum up the flow. To fight this, antifreeze stored in tanks over 40 feet tall flows down the umbilicals to the wells.

Subsea technology is quickly gaining favor in the oil and gas industry and has become a $6.4 billion market. This industry niche has grown at a 23% compound annual rate for the past three years and will most likely continue at that rate for the next few years.