The legacy of wells in Alaska

Before Alaska became a state, it was famous for many things such as gold, furs and oil.  Oil was first produced along Alaska’s north slope in the 1940s when America’s military fleet was converting from coal to oil.  The Naval Petroleum Reserve No. 4 was established in 1923 and the U.S. Navy began exploring in 1944.  Later, the U.S. Geological Survey drilled some wells for scientific research, some still in use today. 

A total of 136 test holes were drilled under two distinct drilling periods, both sponsored by the U.S. Government to explore for oil and gas resources. In the first period, from 1944 to 1952, the U.S. Navy drilled 91 holes. In the second period, from 1975 to 1981, Husky Oil Corporation, working under contract for both the U.S. Navy and USGS, drilled 36 holes. The remaining nine holes were drilled in the Barrow area between 1953 and 1974.

Keep in mind this exploration and research was conducted before the National Environmental Policy Act and these wells were plugged and abandoned with the best technology at the time, if they were plugged at all.

“When they abandoned the wells, they sometimes didn’t want to haul all this stuff back out,” explained petroleum engineer Amanda Eagle, “so they threw a lot of the debris into the well bore and left it.”

The Bureau of Land Management took over management of Naval Petroleum Reserve No. 4 when it was redesignated as the National Petroleum Reserve and jurisdiction was transferred from the Department of the Navy to the Department of the Interior in 1976, and management was further defined in 1981 with the Interior Appropriations Act.  In 1982, the BLM inherited the responsibility to assess, plug, and clean up the wells that the U.S. Navy and USGS left behind.

In 2004, the BLM completed a three-year study of all 136 “legacy” wells as they now have become known.  This summary provided an overview of the work done to remediate these wells and what remained, based upon the threat to human health, safety, and the environment. In 2013, the Helium Act passed providing $50 million for remediation work and the BLM developed a strategic plan prioritizing the remaining wells and how they needed to be remediated.  Due to the success of plugging wells over the past five years, the BLM is preparing an updated strategic report to conclude the remediation of the final 21 wells. This upcoming winter season they plan to plug four wells on the Simpson Peninsula.

Remediation often requires plugging the legacy well, but it could also include removing debris or abandoned structures. Work completed to date includes removing trash, wood, gloves and even a pair of boots from thawed out well bores.  That “stuff” has to be removed before the bore can be successfully plugged with Arctic-grade cement (a mix that cures at much lower temperatures than conventional mixes).

Remote sites, contractor preparations for extreme conditions (including custom-designed rigs and equipment), and the individualized engineering needed for each well add to the complexity of the operation.  Mobilizing equipment to complete the remediation requires airlifting modules to the site because there are no roads to these wells.  Mobilization can only be done in the winter when the tundra is frozen and it takes time to move equipment to the site.  This past winter, the team plugged three.

“Every well is different,” explained Allie Schoessler, petroleum engineering technician. “You plan as best you can — but how you think a well is going to act isn’t always how it responds.”

“And you find stuff that isn’t in the historical record,” added Quinn Sawyer, petroleum engineering technician. “Things like casing strings [incrementally smaller-diameter pipes used in a well bore as it progresses through rock formations], wood, thermistor [temperature sensing] cables, and other debris.”

By the time a well is plugged with several cement plugs at various depths, and the casing has been cut, capped and buried six feet beneath the surface, the operation’s cost has reached hundreds of thousands or millions of dollars per well.