technology

BP Proposes Development With No Pad, Flexible Pipeline

Small accumulations uneconomic with conventional facilities; five-seven year test at Gwyder Bay

The absence of a gravel drilling pad and flexible pipeline distinguish development proposals for a small accumulation at Gwydyr Bay.

BP Exploration (Alaska) Inc. has been working with regulators to find an economic way to develop the small Sagavanirktok/Ivishak find the company made at its Pete's Wicked exploration well in the winter of 1997, BP said, "after the reserves were found too small to justify a conventional development (i.e., involving a gravel road, pad, and pipeline on vertical support members extending from T Pad to the Pete's Wicked location)."

The situation was similar, the company said, for two other small accumulations, also Sagavanirktok/Ivishak discoveries, the Kuparuk River Delta and Point Storkersen wells.

A proposal is now under consideration for a five-to-seven-year test beginning in 1999. No gravel pad would be constructed at the well site - just three 10-12 foot diameter well cellar/house combinations. The Pete's Wicked well would be re-entered during the winter from an ice pad in the Gwydyr Bay area and two additional wells might be drilled from the same ice pad, using conductor pipes previously installed and improved at the time of the Pete's Wicked drilling.

Flexible pipe reusable
Flexible pipe proposed for the project was developed for offshore undersea use, BP said, and has been in common use in the Gulf of Mexico and the North Sea for more than 15 years. Flexible pipelines with high density polyethylene liners have been used on the North Slope at two Prudhoe Bay drill sites "for well tie-in lines for the past three years and have worked well in the Arctic," the company said.

A 4-inch inner diameter line would be used. It is available in one-mile continuous lengths, requiring only three to four joints. With the continuous high density polyethylene liner, BP said the lines are completely corrosion proof. After depletion of the Gwydyr Bay oil, the line could be spooled up and reused in other applications.

Construction-related activity would begin this summer with the ordering of project materials; project construction is slated for January-May 1999.

Approximately 2.02 miles of the line would be in two shallow lakes and approximately 2.5 miles on tundra. The test will include "many different line placement configurations to determine the actual impacts in a scientifically valid manner," BP said.

To allow for caribou movement, some line will be placed directly on the tundra. Between the lakes, a critical caribou crossing area, the line will be raised on seven-foot vertical support members. In other areas, the line will be raised one foot above the tundra on plastic or wooden blocks to allow drainage and movement by flightless molting waterfowl, shorebirds or broods. The line will also be routed to avoid areas of expected high nesting density.

BP developed the plan for Gwydyr Bay in conjunction with the North Slope Borough, the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Department of Interior Bureau of Land Management, the Alaska Department of Natural Resources division of oil and gas, the U.S. Fish and Wildlife Service and the Alaska Department of Fish and Game.

By Kristen Nelson
PNA News Editor