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Alaska's North Slope: Earth Image of the Week September 11, 2009
California's Station Fire from space
Twelve pumping stations were constructed to transport oil from Prudhoe Bay 800 miles southward to Valdez. Pump Station 12 was recently decommissioned due to the decreasing amount of oil being extracted out of the North Slope.
A rare, sunny day across Alaska’s North Slope on September 5 provided a clear view from outer space of North America’s largest oil field.

When NASA’s Terra satellite passed over Prudhoe Bay at midday on Saturday, the waning sun of summer had managed to warm the air at the Deadhorse airport, near the shores of the Arctic Ocean, to a balmy 64 degrees.

In the image to the right captured by the MODIS sensor on Terra, thousands of small lakes can be seen dotting the tundra — in a region normally frozen over except for a brief period of time between June and September.

Because of a layer of permafrost less than 3 feet beneath the surface, the melted snow has no place to soak into the soil.

That results in an abundance of small lakes and ponds, which turn into breeding grounds for voracious swarms of mosquitoes each summer.

Oil was discovered beneath Prudhoe Bay on March 12, 1968, by engineers from what is now called ARCO, and Exxon. It was soon estimated that there were about 25 billion barrels of oil lying beneath the tundra and adjacent coastal waters of the Arctic Ocean.

The 1973 oil crisis quickly made it economically feasible to not only drill more than 1,000 wells in America’s most remote region, but also to construct a pipeline across the state to deliver the crude to tanker ships. The Tran-Alaska Pipeline was completed in 1977, and extends 800 miles south from Prudhoe Bay to the Valdez Marine Terminal.

Between 1977 and 2005, 13 billion barrels of oil were transported through the pipeline. Production peaked in 1998 at 2 million barrels per day, but had fallen to only 943,000 per day by 2005.

The once vast oil reserve was contained in porous rock formations between 5,000 and 20,000 feet beneath the surface. But it has been able to rise to the wellheads under its own geologic pressure, eliminating the need for pumping.

Thirty years of extraction from wells around Prudhoe Bay, and a vast network of satellite oil fields to the east and west, has considerably depleted the amount of oil beneath the region.

British Petroleum estimated in 2006 that only 2 billion barrels of oil remain that can be acquired with current technology.

Image: NASA MODIS Rapid Response System