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Providing coverage of Alaska and northern Canada's oil and gas industry
July 2009

Vol. 14, No. 28 Week of July 12, 2009

BP in Alaska: Evolving oil field technology

Technology, innovation on the North Slope has helped reduce environmental impacts, reducing industry’s footprint

Frank Baker

For Petroleum News

Through decades of oil production at Prudhoe Bay and other North Slope oil fields, producers have significantly advanced technology in drilling, Arctic engineering, waste disposal and environmental management, and have developed better tools to locate underground structures that contain oil. Combined, these advancements have greatly reduced the impact or “footprint” of oil field development on the North Slope.

To locate underground structures that may contain oil, geologists survey land with technologically sophisticated gravity meters and magnetometers. They use seismographs, similar to those that measure earthquakes, to explore what they cannot see by sending sound waves underground and measuring how long it takes the waves to reflect off rock layers and return to the surface. Geologists feed that data into computer models to create 3-dimensional pictures of underground formations. With computerized areal tomography (CAT) scans and magnetic resonance imaging (MRI) — the same technology doctors use to peer inside the human body — they use modern imaging rooms to visualize the presence of oil in the rocks.

This information helps companies pinpoint where to drill. Today’s drilling techniques include extended-reach, horizontal and multilateral wells, which are multiple wells drilled off a common hole to the surface. These wells are based on real-time information about what is happening down-hole. From surface locations miles distant from the down-hole target, they can reach small pockets of oil never thought possible by the Slope’s pioneer drillers.

The advent of new down-hole directional equipment and drilling motors has made it possible to drill new wells with coiled tubing units that for years have been used to perform maintenance work on North Slope wells. With this new method, new wells are drilled through the production tubing of existing wells, eliminating the need to pull the tubing out of the ground as a conventional drilling rig must do. Also, the job can be done with the well’s “Christmas tree,” the surface assembly of valves, in place.

Coiled tubing wells can be drilled at a fraction of the cost of traditional rotary rigs.

Footprint reduction

An immediate benefit of drilling advances and improved waste management techniques has been a marked reduction in the land area needed for oil field development. Wells that once were spaced about 120 feet apart are now drilled as close as 10 feet. With grind-and-inject technology, drilling waste is safely re-injected underground into isolated geologic formations, eliminating the need for surface storage areas, or reserve pits, used during Prudhoe’s early development.

Prudhoe Bay development directly covers about 5,000 acres, or less than 2 percent of the field’s total surface acreage. As an example of evolving technology, the 40,000-acre Alpine field to the west of Prudhoe Bay has been developed from facilities covering about 100 acres or less than 0.2 percent of the land.

Today exploration drilling is conducted from temporary pads of ice that disappear after the well has been drilled, leaving virtually no trace. Construction of pipelines and other facilities is also done during winter from ice roads or pads. From design through construction and operation, there is a continual dialogue between the industry and regulatory agency personnel to ensure the best methods are used to minimize environmental impacts.

Environmental stewardship

More than four decades of oil exploration, development and production on Alaska’s North Slope have resulted in it being one of the most intensively studied and surveyed regions in North America, and the best understood environment of the circumpolar Arctic.

Environmental studies include air and water quality sampling, documenting baseline conditions prior to new developments. The data is used to assist project engineers with the routing and placement of gravel roads and pads to minimize environmental impacts. Examples of such studies include mammals and bird surveys and habitat mapping to determine important wildlife habitats, including those of marine mammals offshore.

Example of studies to support permits include water source sampling for ice road construction and cultural resource clearance to ensure that activities avoid known cultural or historic sites.

Wildlife studies assessed the impact of ongoing operations. Examples include aerial surveys of spectacled eiders as a threatened species, and acoustic surveys of bowhead whales to understand their response to offshore operations, such as at Northstar Island.

Extensive research has shown that North Slope development has had minimal impacts on fish and wildlife populations. For example, the number of Central Arctic Herd caribou moving through the Prudhoe, Kuparuk and Alpine oil fields has increased from 3,000 in 1972, when development began, to about 32,000 today.

More than 200 species of waterfowl and shorebirds migrate to the North Slope each spring. These include Canada geese, snow geese, tundra swans, whitefront geese, loons and waterfowl such as long-tailed duck, pintail, scaup and four species of eider ducks.

Barren-ground grizzly bear, Arctic fox, wolf, Arctic hare, musk oxen, ground squirrel, lemming and other wildlife roam the North Slope as they did prior to development.

Fish such as Arctic char, whitefish and grayling spawn in the upper reaches of rivers such as the Sagavanirktok, Kuparuk, Canning and Colville.

In coordination with the Alaska Department of Natural Resources, National Marine Fisheries Service and other interested agencies, industry expends considerable effort in identifying fish habitat important to life-cycle periods before any development activity can begin.






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