Developing NPR-A: oil, gas, and protected ground.

• Author: Swann, Kirsten
• Position: OIL & GAS

The National Petroleum Reserve-Alaska (NPR-A) is the largest single block of federally managed land in the United States: A 23 million-acre swath of arctic terrain along Alaska's North Slope.

NPR-A encompasses the Inupiaq communities of Barrow, Nuiqsut, Atqasuk, and Wainwright. The landscape is dotted with lakes, rivers, bogs, tundra foothills, and, to the south, the jagged peaks of the Brooks Range. Below the surface lies another natural treasure. NPR-A holds approximately 896 million barrels of oil and about 53 trillion cubic feet of non-associated natural gas, according to the US Geological Survey (USGS).

Oil and gas leasing within NPR-A, authorized under the Naval Petroleum Reserves Production Act of 1976, is overseen by the Bureau of Land Management (BLM). A new Integrated Activity Plan and Environmental Impact Statement was finalized in 2013. Then, in August 2015, one of Alaska's largest oil companies began drilling the first oil development in the petroleum reserve's history.

Despite economic hurdles and regulatory uncertainty, exploration and production at NPR-A continue to move forward.

The first and so far only development to commence drilling within NPR-A is Colville Delta-5 (CD5), a $1 billion investment led by ConocoPhillips. When the petroleum giant began work on its first development wells in August this year, ConocoPhillips Alaska President Joe Marushack called it a "significant milestone."

Indiana-Sized Oil Reserve

Some perspective: The entire NPR-A is approximately the size of the state of Indiana. Established as the Naval Petroleum Reserve No. 4 in 1923, the area was intended to help supply the country's oil needs in times of national crisis, according to the USGS. In the decades since, the NPR-A has been the subject of various explorations. The US Navy, USGS, and the oil and gas industry have all taken a hard look at the area. For years, though, it wasn't considered economically viable to develop within the reserve. Early exploration efforts uncovered no commercial-size deposits, and neither did another round of test drilling conducted in the 1970s.

But advances in technology mean renewed promise for Alaska's smaller fields. Things like 3D seismic profiling, sequence stratigraphy, and wellsite development methods have lowered the cost of exploration and development, putting a new focus on NPR-A, according to USGS.

Geologically, it's a huge area made up of various strata and layered facies thousands of feet below the...