If you could tour the pipeline route

The northern portion of the route begins at Point Thomson, continues west to Prudhoe Bay, then heads south toward Interior Alaska

BILL WHITE

Researcher/writer for the Office of the Federal Coordinator

Alaska LNG project sponsors often remind people it’s really three projects - a gas treatment plant on the North Slope, a long pipeline bisecting the state and a liquefaction plant at coastal Nikiski. Each would cost billions of dollars, and need tons of steel, thousands of workers and years to construct.

But the middle segment of this trinity - the 800-mile natural gas pipeline from Prudhoe Bay to Nikiski - is the symbol of Alaska’s 40-year quest for North Slope natural gas development.

The project sponsors are still working out the exact route for the 42-inch-diameter pipeline, testing soils, searching for earthquake faults, scoping the most buildable corridor with the least environmental impact and the fewest construction problems. It’s all part of their preliminary front-end engineering and design efforts, expected to last through 2015. The “study corridor” is 2,000 feet wide. The pipeline’s ultimate right of way and footprint would be much narrower.

Preliminary maps filed in February 2015 with the Federal Energy Regulatory Commission provide a general path the sponsors and their teams are reviewing.

If you could walk, drive or fly over the route, this is what you would see and could learn about the people and places along the way. (We consulted a variety of public filings from current and past projects along the corridor, as well as other publications, in preparing this narrative.)

Point Thomson: The real starting point

ExxonMobil is leading the Point Thomson development, which is scheduled to start producing natural gas condensate in early 2016. The partners expect that this $4 billion initial production phase will help them master the tricky reservoir’s “plumbing” in anticipation of beginning gas production for the separate Alaska LNG project in the mid-2020s.

Point Thomson lies a few miles west of the Arctic National Wildlife Refuge border and about 60 miles west of the Beaufort Sea coastal community of Kaktovik. Most of Kaktovik’s 250 residents are Inupiat, whose North Slope roots go back thousands of years. The name Kaktovik, or “seining place,” signifies the region’s fishing tradition.

The field and pipeline route lie along the Arctic coast, among the northern-most places in the United States. It can snow there any month, and it’s reliably covered with snow eight months of the year. It is completely sunless about two months a year. During the warmer months the terrain is largely a squishy mass of peaty tundra and other wetlands, including ponds, lakes, streams and braided rivers.

The project sponsors have not decided whether to bury or elevate the pipeline that would carry Point Thomson gas to Prudhoe Bay. In any event, construction would occur during winter, when the ground is frozen.

The pipeline generally would trace the coastline a mile or so inland.

Sedge and dwarf shrubs dominate the vegetation, both well-suited to thrive in cold, soggy soil. A deep permafrost layer slightly below the surface keeps soils waterlogged as moisture can’t filter down.

Numerous freshwater lakes pockmark the flat tundra, providing habitat for ninespine sticklebacks, whitefish, blackfish and others.

Bears - polar and brown - roam the grounds, as do caribou, musk ox, foxes and small mammals such as arctic ground squirrels, collared and brown lemmings, root voles and barren shrews.

The small critters are prey to larger mammals and such birds as raptors and owls. The wetlands support dozens of migratory bird species - including geese, ducks, loons - for nesting and molting in summer. Other areas of Alaska’s North Slope see a much greater density of bird migrations each year.

Near Milepost 20. One-third of the way to Prudhoe, just shy of the 20-mile marker, the gas line would pass south of Badami, an oil field BP started in 1998. Badami has been an inconsistent producer - though a new operator, Savant Alaska, is giving it a try.

Until work started at Point Thomson, Badami was the North Slope’s easternmost field. The liquids that will flow from Point Thomson starting in 2016 will feed into the existing oil pipeline from Badami to Prudhoe Bay.

Near Milepost 24. The gas line would cross three major drainages along the route, and here it would cross the first of them, the Shaviovik River, for the Native word that means “place where there is iron.” The line would encounter many smaller streams along the way, too.

Near Milepost 33. Here lies the second significant river, the Kadleroshilik, a 90-mile-long waterway that empties into the Beaufort Sea. An explorer named the river almost 100 years ago for a 200-foot-tall mound; the name means “possesses something on top.”

Near Milepost 50. The mightiest of the rivers along the pipeline route is the Sagavanirktok, the “strong current” coursing along the Dalton Highway, the lifeline for truck traffic to the North Slope. Here you enter the Prudhoe Bay oil and gas complex - roads, rigs and runways; pipelines, people and power poles. It’s the nation’s largest conventional oil field.

Near Milepost 58. The Point Thomson gas pipeline would reach its endpoint at the new gas treatment plant about eight miles from the Sag River. At this plant, the pipeline’s gas would mix with Prudhoe Bay gas and get processed to remove carbon dioxide and other impurities before starting the 800-mile journey to the LNG terminal. The gas treatment plant would be built near Prudhoe’s massive central gas plant, which has handled the field’s gas production since 1986.

Miles 0-65: Prudhoe Bay and the coastal plain

Prudhoe Bay’s oil and gas production facilities are a complex of pads, wells, pipes, roads, machinery, plants and housing that support production and handling of hundreds of thousands of barrels of oil, tens of millions of gallons of water and billions of cubic feet of natural gas every day. Everything there was installed within the past 40 years or so. Thousands of workers keep it humming.

Equipment mostly gets delivered via one of two routes: one by land and one by sea. The Dalton Highway is the lone road linking Prudhoe to the rest of Alaska, snaking 415 miles south until it connects to the next road north of Fairbanks. West Dock is a 2.7-mile industrial causeway/dock that knifes into the Beaufort Sea north of the oil field. The industry built both to support developing Prudhoe in the 1970s.

Buildings and plants too giant to move by road get delivered by flotillas called sealifts to West Dock during an ice-free summer window. Alaska LNG plans summer sealifts, too. Likely four of them to sail in enormous modules that would be assembled into the multibillion-dollar gas treatment plant.

The Dalton Highway would be a key artery for moving pipe, machinery and people when building the pipeline from Prudhoe Bay to Nikiski. The road would parallel the northern 400 miles or so of the gas pipeline. The mostly gravel highway was named for James W. Dalton, who came from a pioneering sourdough Alaska family and made a name as a territorial-era engineer involved in early North Slope oil exploration.

Milepost 0. The pipeline south would start at the gas treatment plant.

After performing its main job of removing impurities, this plant would chill the gas below 32 degrees and compress the molecules before the gas enters the pipeline.

Chilling the gas keeps the pipeline cold. The pipe would be buried in permafrost in the Arctic and discontinuous permafrost in some soils farther south. A cold pipe keeps the ground frozen.

Compressing the gas - pumping up its pressure - provides energy that propels it through the pipe: The gas would leave the plant, start expanding and thus stream through the pipe. Along the line, a string of compressor stations would regulate the gas temperature and provide propulsion via compression. Movement gradually slows between compressor stations due to the friction of gas molecules against the steel pipe walls.

Near Milepost 5. The pipeline would pass Pump Station 1, the start of the trans-Alaska oil pipeline, which has been carrying North Slope oil since production began in 1977.

Near Milepost 7. The gas pipeline would have exited the main oil-development area by now and would run roughly parallel to the oil pipeline and Dalton Highway for approximately 400 miles.

Roughly Milepost 7 to Milepost 65. Alaska is considered to have 32 ecoregions across the vast state. Alaska LNG and its pipeline would traverse nine of them.

For the northernmost 60 miles or so - at Prudhoe Bay and immediately south - the pipeline would be in what is called the Beaufort Coastal Plain. This area is generally like the land the Point Thomson line would span: flat, wet and treeless, thus windy. Ice-rich organic silt overlays coarse sands and gravels, which in turn overlay permafrost. Sedges, grasses and mosses tend to dominate the vegetation woven into this soggy soil.

As the elevation slowly rises toward the Brooks Range to the south, the soil drains better. Dwarf shrubs can be found, typically no taller than soda bottles.

The pipeline would weave along the better ground through this terrain to minimize its footprint in wetlands. As with the Point Thomson pipeline and much of the entire pipeline, construction would occur here in winter when the ground is frozen. A special federal Clean Water Act permit is needed to discharge dredged or fill materials into wetlands. The project sponsors as of early 2015 were studying whether to elevate the pipeline above ground for the first 60 miles or so rather than burying it.

Near Milepost 20. The pipeline would come up close to the Dalton Highway for the first time. The Sagavanirktok River, the major drainage in the area, lies just east of the road.

Near Milepost 35. Across the Sag River to the east are the iron-tinged Franklin Bluffs, a visual departure from the Arctic plain’s typical flatness and a foreshadower of the Brooks Range ahead.

The bluffs aren’t the only contour relief here, however. To the west, a pingo called “Berry” is visible. Pingos are mounds of earth-covered ice. Some are quite large, looming hundreds of feet above the tundra. With their relatively good drainage, they tend to provide botanical contrast to the wet, flat surrounding tundra, especially on their south-facing slopes.

Besides members of construction crews, caribou would be the most likely large mammals encountered in this vicinity. If a grazing caribou bull suddenly darts across the tundra, the likely reason is warble flies. They don’t bite or sting, but they can lay eggs that can grow into large grubs under the caribou skin.

A rare brown bear or wolf siting also could occur. Small mammals are present - shrews, voles and arctic ground squirrels.

The wetlands also provide seasonal habitat for migratory birds from around the world. The area is a hotspot for bird-watchers, as migratory birds nest and breed on the Arctic coastal plain, including King eiders, spectacled eiders, geese and loons. Rock and willow ptarmigan are widespread here, too.

Near Milepost 65. The pipeline would pass near Pump Station 2. This station was built for the oil pipeline, although it’s no longer used. As compressor stations help propel pipeline gas, pump stations keep pipeline oil moving.

The initial gas pipeline corridor veers west of the oil pipeline and Dalton Highway for about 20 miles near Pump Station 2.

Nonetheless, Pump Station 2 is symbolic of what lies ahead: the Brooks Range, the first of two major mountain ranges the gas pipeline would surmount. Owners of the oil pipeline built three pump stations to help the oil get up and over the steep Brooks. Two are still used today.

Editor’s note: This is a reprint from the Office of the Federal Coordinator, Alaska Natural Gas Transportation Projects, online at www.arcticgas.gov/if-you-could-tour-pipeline-route. The Office of the Federal Coordinator closed March 7. Until further notice, this website is preserved for research and informational purposes by the U.S. Arctic Research Commission and is administered by the Alaska Resources Library and Information Services at the University of Alaska Anchorage. Additional portions of this story will run in subsequent issues of Petroleum News.