Exploration and production companies, despite a reported worldwide shortage of high-specification offshore rigs, have managed to set a new record for the number of “ultra-deepwater” floaters currently drilling prospects and development wells in the U.S. Gulf of Mexico.
For the first time, 15 rigs are drilling in 5,000 feet of water or greater, a depth range established by the U.S. Minerals Management Service separating the deep from the ultra-deep in the U.S. Gulf.
Nearly half of the 33 rigs reportedly drilling in deeper waters of the Gulf were operating in the ultra-deep, according to information furnished by MMS. The remaining 18 deepwater rigs were drilling in water depths ranging from 1,000 feet to 5,000 feet, also an MMS drilling benchmark.
“The continued increase in drilling activity is a show of confidence in the resource potential of the Gulf’s ultra-deepwater frontier,” MMS Director Randall Luthi said in a press release issued Aug. 14.
BP Exploration and Production is currently the most active player in the ultra-deep, with four rigs currently operating, according to MMS.
One BP well is being drilled on Mississippi Canyon Block 775 from Transocean’s Discoverer Enterprise drillship at Thunder Horse North in 5,673 feet of water, while a second BP well is being drilled on Mississippi Canyon block 778 from the Thunder Horse PDQ at Thunder Horse South in 6,033 feet of water. The largest discovery ever in the U.S. Gulf, Thunder Horse is expected to begin production in the later half of 2008, following several delays, in part due to faulty subsea equipment. The field originally was to come on stream in 2005.
BP also is drilling at its Atlantis field on Green Canyon Block 743, another production startup that was delayed because of equipment problems. The well is being drilled from GlobalSantaFe’s Development Driller II rig in 6,822 feet of water. Additionally, BP is using Transocean’s Deepwater Horizon to drill a prospect on Keathley Canyon Block 244, in 5,431 feet of water.
Chevron has three rigs operatingChevron is currently operating three ultra-deepwater rigs in water depths ranging from 5,232 to 6,959 feet. The package includes an addition well at its Walker Ridge block 758 Jack discovery. Jack is a high-profile prospect because of a recent production test from one of its appraisal wells proving the Gulf’s immense lower tertiary trend could produce in commercial volumes.
Chevron is doing appraisal work at its Big Foot discovery on Walker Ridge block 29, located in 5,232 feet of water. Chevron is using the Ensco 7500 rig. The company also is drilling at its Bob North prospect on Mississippi Canyon block 860, in 5,667 feet of water, using Transocean’s Discoverer Deep Seas rig.
Shell Offshore is currently operating two ultra-deepwater rigs in the U.S. Gulf, including one at its Great White lower tertiary field, one of three Alaminos Canyon discoveries that will anchor the Perdido central production facility, scheduled to come on stream in 2009. Shell is using Noble’s Clyde Boudreaux rig to drill in 7,819 feet of water on Alaminos Canyon block 857.
Shell also is drilling what looks like an exploration well on an unnamed prospect on DeSoto Canyon block 353, located in the Eastern Gulf. Shell is using Transocean’s Deepwater Nautilus to drill in 7,457 feet of water.
ExxonMobil is currently drilling a well at its Brontosaurus North prospect on Alaminos Canyon block 731, using the Ocean Eirik Raude rig in 8,694 feet of water.
Other companies drilling in ultra-deepwaters include Devon Energy, BHP Billion, Woodside Energy Hydo Gulf of Mexico and Kerr-McGee, a subsidiary of Anadarko.
Most production from 1,000-plus water depthsAdvances also have been made in the production area, MMS said, noting the July startup of Independence Hub, a semisubmersible gas processing platform located in 8,000 feet of water and operated by Anadarko Petroleum. It is the deepest production platform ever installed and also the world’s largest offshore natural gas processing facility. The project will produce natural gas from 15 subsea wells in a bevy of fields when fully operational.
Before Independence Hub came on stream, the production facility in the deepest water depth was the Na KiKa floating production system located in 6,340 feet of water, operated by Shell and BP.
Currently, 70 percent of the Gulf’s oil production comes from leases in water depths greater than 1,000 feet, while 40 percent of the natural gas production in the Gulf comes from leases in those same water depths. As of April, the Gulf’s total daily production was estimated at 1.3 million barrels of oil per day and 7.7 billion cubic feet of gas per day.
Several new drilling rigs are being built for use in the deepwater Gulf, MMS said, noting that the rigs range from drillships to semisubmersibles and will be capable of operating in water depths up to 12,000 feet. Some of these new rigs will be ready as early as summer 2008 and others are expected to be operational by the second half of 2009, MMS said.
“The offshore oil and gas industry is facing frontier-like conditions and developing advanced technology to explore the ultra-deep Gulf waters in order to secure the nation’s energy production,” Luthi said.