WSJ:

FAIRBANKS, Alaska—When the famed Trans Alaska Pipeline carried two million barrels of oil a day, the naturally warm crude surged 800 miles to the Port of Valdez in three days and arrived at a temperature of about 100 degrees.
Now, dwindling oil production along Alaska’s northern edge means the pipeline carries less than one-third the volume it once did—and the crude takes five times as long to get to its destination.
That leisurely flow means the oil is above ground longer and more exposed to Alaska’s frigid weather; the crude sometimes arrives chilled to 40 degrees. As the flow and temperature continue to drop, experts say the risks of a clog or corrosion increase, as do the odds of ruptures and spills.
Unless a technological solution can be found, the arcane physics of crude flow may force the multibillion dollar, 48-inch-wide steel pipeline to shut down—and determine the fate of the largest oil field ever found in the U.S.
There’s one other, seemingly simple fix: Add more oil.
“If I could ask for one thing, it is to figure out how to get more oil into this pipe,” says Tom Barrett, president of the pipeline’s owner, Alyeska Pipeline Service Co.
But production from Alaska’s giant oil fields has been falling for years. Turning that around would require drilling in new areas, some of them environmentally sensitive and most controlled by the federal government.
Saving the pipeline has become a political issue in Alaska. The pipeline, which employs 2,000 people, still delivers more than 11% of the oil produced in the U.S. Almost all of it ends up in refineries in Washington, California and Hawaii. The end of the pipeline would likely translate into higher gasoline prices, which hit an average of $3.98 a gallon last week, the highest in nearly three years.
Oil companies and many Alaskan officials argue more lands should be opened to drilling so that the pipeline can get the crude it needs to flow fast and safely. Royal Dutch Shell PLC, which wants to drill off the state’s coast, recently met with senior White House officials to press its case.

The rest here.