Imagine standing on a rubber raft and sticking a really long straw into a pond in hopes of sipping a soft drink buried on the bottom. That is what drilling for oil is like on the new frontier, kilometres under the sea floor in the Gulf of Mexico.
The challenge is immediately clear as you step off a helicopter on to the Noble Amos Runner, a 29 000-tonne rig floating 280km south of New Orleans.
It bobs and rolls. The crew keep it stable as technicians steer a drill toward pay dirt. The bit is at the end of a pipe through 2 200m of water and 8km into the sea floor, pushing deeper as every joint is added.
”It does get your adrenalin going,” says Mike Simon, a 32-year-old from Alabama, who does his job with one foot on an accelerator, one hand on a brake, one eye on a computer monitor and the other on the spinning drill out his window.
As easier-to-reach oil deposits run dry, energy companies are venturing further out into the frontier for new reserves to quench the growing thirst for oil.
The United States Minerals Management Service defines deepwater as below about 300m, a feat first achieved in the 1970s. But improving technology for exploration and production is bringing oil from much deeper water within reach. The new technology could expand deepwater production around the globe.
The well that Noble is drilling, dubbed Mission Deep by owners Anadarko Petroleum and Devon Energy, is one of more than two dozen finds below 2 100m since 1999.
It is not even close to a depth record. Wells have been drilled through 10 000 feet of water and 10 360m into the earth, although production from ultradeep water remains a challenge.
Deepwater now accounts for 70% of oil production in the Gulf, up from 20% 10 years ago. Deepwater gas is 38% of total Gulf production, up from 5,5% in 1996. The Gulf delivers about a quarter of US production.
Expenses
Costs are high, as much as $100-million per well and $2-billion to develop a field, but production rates — and expectations — are high. Some deepwater platforms produce 200 000 barrels per day (bpd) versus 5 000 or 10 000 bpd closer to shore.
”At $60 a barrel, you can get your money back pretty fast,” says Mark Burns, Noble vice-president for Gulf operations.
In 100 days of drilling, the Runner hit a 76m-thick band of oil-bearing rock about 7,6km below the sea floor in the geologic layer known as Miocene. It is pushing on to 8,8km to look in the Lower Tertiary layer.
Citing a dozen recent Tertiary discoveries, some predict there are reserves of three billion to 15-billion barrels of oil and gas at the lower level, a find as dramatic as Alaska 40 years ago. At the higher estimate, that would add 50% to US domestic reserves, but would make only a small dent in US imports of 13-million bpd.
”It’s early in the life of the play, so we have to be cautious,” Tony Vaughn, vice-president and head of Devon’s Gulf division, says of the estimates.
Nothing about deepwater drilling is easy. Currents associated with the Gulf Stream, which flows out of the Gulf and warms Western Europe, are troublesome and unpredictable in the deep. Sometimes drilling has to be suspended to keep the pipe string from breaking.
On the sea floor, water pressures are enormous and temperatures frigid, requiring heaters or additives to keep oil flowing. Deep in the Earth, pressures reach about 1 400kg force per square centimetre and temperatures 200 degrees Celsius.
Anadarko has not set a target date for Mission Deep production, spokesperson John Christiansen says. It can take 10 years from the time the lease was purchased from the government — 1998 in the case of Mission Deep.
To get the oil and gas to shore, companies have to perfect ultradeep water production equipment and lay pipelines or find other ways to market.
”As you go into deep water, it’s mostly canyons,” says Mike Conner, chief of technical assessment in the Gulf for the US Minerals Management Service. ”You have problems getting the path of least misery back to shore.”
The US Minerals Management Service is considering the Gulf’s first Floating Production Storage and Offloading systems — essentially big tankers that store oil until smaller ships can take it ashore. The system is in use elsewhere, but has not been needed in the Gulf because pipelines are everywhere in the shallows.
None of these problems are show stoppers if prices stay high, Conner says. ”It’s just a matter of economics.” — Reuters