WEATHER, SAFETY WOES HIT N. SEA

Severe weather continued to plague North Sea producers last week with waves reaching 40 ft and winds gusting to more than 100 mph. Norway's state owned Den norske stats oljeselskap AS was most affected by storms the week prior but narrowly avoided having to shut in Statfjord and Gullfaks oil fields in the Norwegian North Sea. A Statoil official said Jan. 20 production had been decreased and increased several times during the preceding few days, but tankers had been able to load at various

Jan. 26, 1993

6 min read

Severe weather continued to plague North Sea producers last week with waves reaching 40 ft and winds gusting to more than 100 mph.

Norway's state owned Den norske stats oljeselskap AS was most affected by storms the week prior but narrowly avoided having to shut in Statfjord and Gullfaks oil fields in the Norwegian North Sea.

A Statoil official said Jan. 20 production had been decreased and increased several times during the preceding few days, but tankers had been able to load at various times.

Meantime' the spells of inclement weather did not prevent Statoil from exceeding its world record for an extended reach well in Statfjord field. On Jan. 13, Statoil's CO-2 water injection well drilled from Statfjord C platform passed the 19,905 ft mark that was a record for an extended reach well set in 1991 from the same platform (OGJ, Apr. 15, 1991, p. 31). The target reach is 27,800 ft, which Statoil hopes to achieve this month.

Statoil also expects the well to surpass its world record for horizontal displacement, also set in 1991 from the same platform (OGJ, Nov. 18, 1991, p. 26).

Safety concerns were highlighted elsewhere in the North Sea involving a fire that caused evacuation of a drilling rig in the Norwegian sector and a minor oil spill that shut down a platform in the U.K. sector.

In North Sea development news, Total Oil Marine plc let a 45 million ($69 million) contract to Sedco Forex Drilling Services Ltd., Aberdeen, for conversion of the Sedco 706 semisubmersible rig to a tender support vessel to assist in developing Dunbar field on North Sea Block 3/14a in 1994. In addition to the conversion, the contract covers completion of six pre-drilled wells and drilling 14 development wells.

STATOIL PRODUCTION

Oil flows from Statfjord and Gullfaks averaged about three fourths of their normal volume of 700,000 b/d and 470,000 b/d, respectively, last week. The previous week, four tankers began loading crude from Statfjord and Gullfaks just after midnight Jan. 14, enabling Statoil to avoid cutting production from the fields at the time because of full storage tanks.

Statoil said a lull in the weather at 10 a.m. Jan. 14 allowed the four tankers to hook up, but two had to disconnect after 4 hr loading and were waiting to return. Two more tankers were waiting to load and one was on its way to the fields.

Statoil at the time hoped to load five tankers within 24 hr, taking 4.3 million bbl of oil from the storage tanks. This temporarily took pressure off Statfjord and Gullfaks production, which for a time returned to nearly full volume.

OTHER PROJECTS

Oil flow from Saga Petroleum AS' Snorre field, previously producing 120,000 b/d through Statfjord A, also fell by about one fourth last week.

Mobil North Sea Ltd. slashed production Jan. 18 to 20,000 b/d from its 110,000 b/d Beryl field in the U.K. sector. Mobil said Jan. 20 the rough weather had resulted in deferred production of 665,000 bbl of oil to date. Beryl began producing at the reduced rate as the field storage tank approached capacity, although a tanker moored nearby was ready to begin loading as soon as conditions allowed.

Buchan oil field production resumed Jan. 15 for BP Exploration Operating Co. and remained on stream through presstime last week. However, Donan oil field was still shut down Jan. 20, with the Seillean production vessel on location and ready to reconnect.

The Shell-Esso combine's Kittiwake field production was up and down during the week, although an official said a tanker had been able to load in the field.

Norske Shell AS at midweek still was awaiting a 2 day weather window to move Draugen platform topsides out of Stavanger and to a deepwater commissioning site at Vats. An official said more storms were predicted and termed the week's weather "exceptionally awful."

RIG FIRE, OIL SPILL

A fire broke out on Smedvig AS' West Alpha drilling rig Jan. 13, causing evacuation of 72 crew members, reported Agence France Presse, a Paris news agency. There were no reports of injury or details about damage or how the fire started or was contained. No location was given other than in the Norwegian North Sea.

The rig was working under contract to Elf Petroleum Norway.

In the U.K. North Sea, more than 80 workers were evacuated Jan. 13 from Thistle platform after an oil and gas leak led to automatic shutdown of the field. A plug failure on the main oil line was cited as the cause of the leak. Operator BP said oil and gas leaked into the crude pumping area and about 50 bbl of oil spilled into the water. Nonessential crew were taken off the platform but returned later that day. Thistle had 141 persons on board at the time.

BP said production was unlikely to restart before Jan. 16. Thistle, on Block 211/18a, produces about 20,000 b/d of oil.

Two BP engineers and three Health & Safety Executive inspectors were sent to the platform Jan. 14 to determine the cause of the failure.

DUNBAR DEVELOPMENT

Modifications to the Sedco semisubmersible are to begin in July-August 1994 and take 2 months.

They will include installation of a walkway linking it to the Dunbar platform, mud storage and mud pumps, flexible hoses to send mud and cement to the platform, and a mud return on the gangway. The uses of flexible hoses will enable the rig to stand off during bad weather while continuing to drill. Lifeboats also will need to be repositioned.

Peter McDonnell, rig manager, said the visit to the shipyard also will be used to ensure the rig meets U.K. fourth edition offshore drilling regulations and the safety case required by the Health & Safety Executive.

Sedco 706 will move into the field in fourth quarter 1994 to tie back and complete the predrilled wells. Development drilling will follow and is scheduled to take about 900 days.

The first of the predrilled wells will be reentered in February by Santa Fe Drilling Co. (North Sea) Ltd., which will use the Santa Fe 133 rig for the six wells. Total said Dunbar's medium size called for a minimum facilities to make development viable, so the field will be developed as a satellite to North Alwyn (OGJ, Oct. 26, 1992, p. 37). The platform will have 28 well slots and be operated by a team of 16.

Dunbar, 25 km south of Total's North Alwyn field, holds reserves of 120 million bbl of oil and 500 bcf of gas. Start-up is scheduled for December 1994, and field life is estimated at 18 years. Oil and gas will be transported to North Alwyn, from where oil will be exported to Sullom Voe. Gas will go to the Frigg network for transportation to St. Fergus.

Total is operator of Dunbar, with a 33.4% interest. Elf Exploration U.K. plc holds the remaining 66.6%.