GULF OF MEXICO

By early 2010, the Big 3 are expected to reach their combined designed production capacity of 575,000 b/d of oil. MMS reports that total production from the federal GoM averaged 1.3 MMb/d in 2008 before hurricanes Gustav and Ike impacted supply.

Atlantis: Production from Atlantis field began in October 2007. The initial wells are in the Atlantis South area, with additional drilling planned in Atlantis North to increase production to peak capacity. At least 18 subsea wells are expected to be connected to the field’s semisubmersible production platform which is designed to handle 200,000 b/d of oil and 180 MMcf/d of natural gas.

At the time of first oil, the platform was the deepest floating oil and gas production facility in the world, moored in 7,070 ft (2,155 m) of water on Green Canyon block 699.

BP operates Atlantis with a 56% working interest. BHP Billiton holds the remaining 44% interest.

Thunder Horse: BP started flowing its third and fourth wells at the Thunder Horse field in 4Q 2008, bringing total production to more than 200,000 boe/d. Additional wells are scheduled to come online from the Thunder Horse North field in the first half of this year. Full field development is expected to include at least 25 subsea wells.

TheThunder Horse semisubmersible production, drilling, and quarters platform is fitted with capacity to process 250,000 b/d of oil and 200 MMcf/d of natural gas. It is moored in 6,050 ft (1,844 m) of water in Mississippi Canyon block 778.

BP operates Thunder Horse field with a 75% working interest. ExxonMobil holds the remaining 25% interest.

Tahiti: First production from Tahiti field is expected in the third quarter of this year. Field development includes subsea wells from two drill centers connected to a truss spar in 4,000 ft (1,219 m) of water on Green Canyon block 640. The platform is designed with capacity to process 125,000 b/d of oil and 70 MMcf/d of natural gas.

At print, installation of the platform’s hull and topsides were complete and platform commissioning was under way.

Chevron operates Tahiti with a 58% working interest. Partners are StatoilHydro (25%) and Total (17%).

Other deepwater floating production systems expected to add to oil capacity this year include: BHP-operatedShenzi TLP (100,000 b/d capacity), Murphy-operated semisubmersible Thunder Hawk (45,000 b/d capacity, expandable to 60,000), Helix-operated Phoenix floating production unit (30,000 b/d capacity), and ATP-operated Mirage MinDOC (25,000 b/d capacity).

Deepwater discoveries keep pace as drilling falls

Total wells spudded in the Gulf of Mexico in 2008 as of presstime was down about 17% from 2007, likely due in part to disruptions from hurricanes Gustav and Ike. But deepwater discoveries are about on par year-over-year, with operators reporting nine successful wells in 2008.

Gladden, Anduin West: Newfield Exploration made two deepwater discoveries: Gladden and Anduin West. The Gladden discovery in Mississippi Canyon block 800 in 3,116 ft (950 m) of water found 80 ft (24 m) of net oil while the Anduin West discovery in Mississippi Canyon block 754 in 2,696 ft (822 m) of water hit 30 ft (9 m) of net gas and condensate.

First production from both Newfield-operated fields is expected in late 2009 via subsea tieback to ATP-operatedInnovator moored in Mississippi Canyon block 711.

Dalmatian: Murphy Oil hit pay with its Dalmatian exploration well in DeSoto Canyon block 48. The Murphy-operated well, drilled in 5,900 ft (1,798 m) of water, encountered approximately 120 ft (37 m) measured depth of net gas pay. The company plans to develop the field via subsea tieback to existing area infrastructure.

Freedom/Gunflint: BP made an oil discovery at the Freedom/Gunflint prospect on Mississippi Canyon block 948 in 6,100 ft (1,860 m) of water. The well, drilled to 29,280 ft (8,927 m) TD, encountered greater than 550 net ft (168 m) of hydrocarbon-bearing sands in Middle and Lower Miocene reservoirs.

An appraisal well is planned in the second half of 2009/early 2010. Pending well results, development by floating production system is likely no earlier than 2013.

Geauxpher: Mariner Energy hit gas at its Geauxpher prospect on Garden Banks block 462. The well was drilled in 2,700 ft (823 m) of water to 23,156 ft (7,058 m) measured depth. Mariner plans to develop the field as a two-well, 40-mi (64-km) subsea tieback to an existing fixed platform in Garden Banks block 72. First production is expected in the first quarter of this year.

GC 448, MC 72: LLOG Exploration made deepwater discoveries in Mississippi Canyon block 72 and Green Canyon block 448.

The MC 72 well penetrated over 100 ft (30 m) of gross gas-filled sand. Plans are to tie back the well subsea to the Pompano platform in Viosca Knoll block 989. First production was expected by end-2008.

The GC 448 well penetrated over 85 ft (26 m) of oil-bearing sand. Plans are to sidetrack the well to an updip target. Pending appraisal results, the well is expected to be completed subsea with first production anticipated in late 2009 or early 2010.

Kodiak: BP made an oil discovery at its Kodiak prospect in Mississippi Canyon block 771. The well was drilled in 5,000 ft (1,500 m) of water to 31,150 ft (9,494 m) TD. It encountered 500 net ft (152 m) of hydrocarbon-bearing sands in Middle and Lower Miocene reservoirs. Appraisal drilling is planned to determine the size and commerciality of the discovery.

Tortuga: Noble Energy hit gas at the Tortuga prospect in Mississippi Canyon block 561. The well, drilled in 6,500 ft (1,981 m) water depth to 19,885 ft (6,061 m) TD, encountered natural gas in a secondary objective. The primary objective was determined to be wet.

Tortuga and BP-operated discovery Isabel in adjacent MC 562, form part of a larger area called Galapagos. Noble plans an additional exploration test in the area in 2009 which should help in the overall appraisal of the area. Phase 1 development could include three or four subsea wells tied back to existing infrastructure, with first production in 2010.

In other notable deepwater news in 2008, Hess moved forward with its Pony project with the award of a FEED contract to INTECSEA for the subsea, TLP hull, and mooring system. The work began in mid-September 2008 and is expected to be completed in this quarter.

The subsea scope calls for the design of all subsea systems including trees, jumpers, flowlines, umbilicals, risers, subsea control systems, and other subsea structures.

The TLP hull and mooring scope includes hull sizing and global performance, design of the hull structure, hull systems, and the tendon moorings and foundations. The company also will carry out procurement support including development of procurement packages for long-lead components, and construction support.

ThePony TLP is being designed with a conventional four-column hull to support subsea trees. The field will be developed with seven production wells, three water injection wells, and a possible step out of 22 mi (35 km) to Ness. Pony is in Green Canyon blocks 468 and 469 in 3,200 to 3,800 ft (975 to 1,158 m) water depth. Sanction is expected by the end of this year.

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Weakening shallow water market forces Hercules to stack rigs

The deteriorating shallow water market in the Gulf of Mexico is forcing the rig contactor with the most exposure to this market segment to stack rigs. At print, Hercules Offshore had stacked seven rigs and seven inland barges, and analysts predict the company will be forced to stack additional rigs this year.

Meanwhile, leading edge day rates for commodity jackups in the GoM have fallen about 20% below peak, according to Raymond James. The analyst expects this decline will continue with more than 70 newbuild jackups set to hit the water by the end of 2010, 70% of which are uncontracted. This would represent a 20% increase in jackup capacity, the analyst says.

Rope deployment innovation proven at Independence Hub

A new fiber rope deployment system (FRDS) contributed to the successful subsea installations made at Independence Hub in about 9,000 ft (2,743 m) of water in the Gulf of Mexico. In a paper for the Deep Offshore Technology International Asia/Pacific Conference & Exhibition in Perth, Australia, Murray Dick of Subsea 7 described how the system works.

The newly developed fiber rope and FRDS was used for all the deepwater lifts including installation of one wellhead as well as umbilicals, manifolds, subsea distribution units, stab and hinge over structures, flowline jumpers, and electrical and hydraulic flying leads, said Dick. The system was necessary because the depths exceeded that of existing crane and winch wires on the installation vessel.

In describing the installation events, Dick pointed out that the methods used to install the equipment generally were similar to those used to install equipment in shallower water. In fact, Dick said, the project shows that the industry has not yet reached the practical depth limit for subsea oilfield equipment installation.

The main parts of the FRDS are:

• CTCU: Six sheaves with individual drives de-tension the rope
• Storage winch to store the rope at low tension and to assure a constant back tension for the CTCU
• Inboard damping device: to smooth the tension between the CTCU and the storage winch, to assure constant back tension for the CTCU, and to give constant spooling tension
• Outboard damping device used for constant tension control
• Accumulator system: to reduce power peaks during active heave compensation
• HPU: hydraulic power pack
• Computer for dynamic control of individual machines and interactions between machines, monitoring and alarm functions, and rope management system.

Winch performance:

• Load capacity -- 50 metric tons (55 tons)
• AHC speed capacity -- 2 m/s
• Deployment speed @ 50 metric tons -- 1 m/s
• Recovery speed @ 46 metric tons (51 tons) -- 0.5 m/s

Bend optimized braid rope of about 56 mm (2.2 in.), 12 by 12 strand MBL 218 metric tons (240 tons), which weighed 2.5 kg/m dry and 0.5 kg/m wet was used.