The Barrow gas fields are unique in Alaska hydrocarbon development.
The three natural gas fields in the vicinity of Utqiagvik, formerly Barrow, are the only oil or natural gas properties in the state operated by a public entity for public consumption.
The fields - South Barrow, East Barrow and Walakpa - are also the only place on the North Slope where natural gas is being used for a purpose other than field operations.
Federal contractors discovered the three fields on separate expeditions throughout the region between the late 1940s and the 1980s. The North Slope Borough has operated the fields for decades. The fields have generally required minimal development, aside from a $92 million rejuvenation program launched in 2011 to combat declining production.
With that effort, the city commissioned the Savik 1 and 2 wells at the East Barrow field and the Walakpa 11, 12, and 13 wells at the Walakpa field. By improving deliverability, the city of Utqiagvik can now rely on natural gas for its energy needs even during cold snaps or during maintenance activities, instead of switching to diesel as an alternative.
South BarrowThe U.S. Navy discovered the South Barrow field with the 2,505-foot South Barrow No. 2 well in 1948, during its initial wave of National Petroleum Reserve-Alaska exploration.
Production began the following year. Drilling continued for decades, with 13 new wells drilled and one existing well deepened by 1987, according to the Alaska Oil and Gas Conservation Commission. Production peaked at some 3.5 million cubic feet per day in November 1981. The field is now used primarily to meet peak demand during the winter.
The South Barrow field produced consistently from 1950 through 1990, at which point operators began to suspend production sporadically. The field was shut-in with increasing regularly through the 2000s, and today produces only a few months each year at most.
The South Barrow Test Well No. 6 flowed for a total of 61 days from May through August 2018, according to the Alaska Oil and Gas Conservation Commission, producing some 28 million cubic feet or slightly more than 459,000 cubic feet per day. The production was the first reported from the South Barrow field since November 2015.
According to the AOGCC, cumulative production at the South Barrow field is nearly 24 billion cubic feet. Geologists had originally expected the field to produce some 32 bcf.
East BarrowThe U.S. Geological Survey discovered the East Barrow field with the South Barrow No. 12 well in 1974, during the second wave of oil and gas exploration in the NPR-A.
Production began in December 1981. Drilling continued through 1990, with eight wells total. East Barrow production peaked at some 2.75 million cubic feet per day in 1984.
According to the AOGCC, cumulative production at East Barrow was 9.2 billion cubic feet through the end of 2016, 9.3 billion cubic feet through the end of 2017 and 9.4 billion cubic feet through the first six months of 2018. The current cumulative total is well above the originally estimated 6.2 billion cubic feet in place for the East Barrow field. Utqiagvik attributes the productivity to methane hydrates - natural gas molecules trapped inside cages of ice and released through pressure changes at the aging field.
WalakpaWorking under a Navy contract, Husky Oil discovered the Walakpa field with the 3,666-foot Walakpa No. 1 well in the 1980s. Production began in the early 1990s. The field has peaked above 5 million cubic feet per day numerous times, including in early 2013.
Today, Walakpa accounts for most of the gas delivered to Utqiagvik. According to the AOGCC, cumulative production was some 31.6 billion cubic feet through the end of 2015, 31.7 billion cubic feet through the end of 2016, 31.9 billion cubic feet through the end of 2017 and more than 32 billion cubic feet through the end of June 2018.
The South Barrow and East Barrow reservoirs have a stratigraphic setting similar to the Alpine oil field. Walakpa is in the Pebble Shale unit, a major North Slope source rock.