NORTH SLOPE SEALIFT GETS UNDER WAY

The summer sealift of Alaskan North Slope equipment, including the heaviest modules built for giant Prudhoe Bay field, is under way.

Meantime, ARCO Alaska Inc. plans to build about 30 modules in Alaska related to five projects in Kuparuk River field on the North Slope and Beluga River gas field in Cook Inlet.

SEALIFT BEGINS

Barges carrying modules for Prudhoe Bay's $450 million gas handling expansion (GHX-1) project departed Portland, Ore., July 22 on a 3,000 mile voyage to Prudhoe Bay.

The barges are carrying two 11 story turbine compressor modules weighing about 3,200 tons each. Intended for Prudhoe's central compressor plant, each is about 200 ft long, 95 ft wide, and 110 ft tall. In addition, the barges are carrying five other modules for GHX-1 work.

GHX-1 is intended to handle increasing production of Prudhoe Bay associated natural gas as crude production declines. GHX-1 is expected to result in incremental recovery of at least 400 million bbl of oil during field life.

Prudhoe Bay operators expect GHX-1 to hike field production by more than 90,000 b/d, helping to partially stem the field's decline, said ARCO Alaska Inc., operator of the field's eastern half. BP Exploration (Alaska) Inc. operates the western half of the field.

Prudhoe Bay produces about 1.3 million b/d of black oil, down from the 1.5 million b/d it has produced since it reached that decreed limit in 1980 and into 1988.

Prudhoe Bay's decline has sliced North Slope production to 1.7 million b/d, about one fourth of the U.S. total and down from a peak of 1.98 million b/d in 1988.

In addition to the GHX modules, this year's North Slope sealift includes pipe and other equipment for laying a new 60 in. pipeline to carry gas from Prudhoe Bay production facilities to the central gas facility operated by ARCO.

Ralph M. Parsons Co., Pasadena, Calif., handled design of the GHX-1 modules, Wright, Schuchart & Harbor Co., Seattle, built them, and H.C. Price Co., Anchorage, Alas., will install them.

SEALIFT DETAILS

In all, more than 8,641 tons of gas handling modules, turbine compressor modules, pipe racks, and other oil field equipment were loaded out of Portland Ship Repair Yard (PSRY) July 16-17, PSRY reported.

Wright Schuchart overcame a late start, caused by a change in project scope and late arrival of equipment, and finished the $40 million project on schedule in 11 months, PSRY said.

In addition to oil field equipment, the contractor loaded about 350 tons of general cargo onto two 100 ft by 400 ft Crowley Maritime barges.

Loading involved submerging a dry dock, positioning the barges onboard, and raising the dock.

The big GHX-1 modules were rolled onto the barges across a special bridge structure connecting the shore and module launch system to the dock.

The summer sealift has been an annual event-except for 1988-since the early 1970s, when Prudhoe Bay development and construction of the Trans-Alaska Pipeline System began.

It is timed to take advantage of the brief summer weather window when arctic pack ice moves offshore, allowing barges to transit the Beaufort Sea.

The last major sealift was in 1987, when modules intended for Endicott oil field-the first U.S. arctic offshore development-were shipped (OGJ, May 25, 1987, p. 30).

A small sealift last year carried modules designed to boost Prudhoe Bay's water handling capacity (OGJ, Aug. 21, 1989, p. 32).

ARCO PROJECT PLANS

ARCO will seek bids in August for its Alaskan oil field construction work to be carried out the next 16 months.

The projects involve construction of 22 modules for two new wellsite production facilities at Kuparuk.

Other Kuparuk modules are intended for environmental improvements to field flare systems and increased production at existing wellsites.

Cook Inlet work will involve construction of three modules to boost production in Beluga River field.

The first of five contracts will be awarded in September, and work is to begin in October. Included in the bids are module construction, transport to the fields, interconnection and start-up work, procurement, and warehousing. Each of the projects will last 3-6 months.

This is the second time modules will have been built in Alaska for Kuparuk and the first for Cook Inlet. ARCO previously built nine modules in Alaska for Kuparuk and Prudhoe Bay.