The angst ringing through the Alaska oil patch is barely heard at the Barrow gas fields.
The South Barrow, East Barrow and Walakpa fields have been providing fuel for the city of Barrow for decades. A pair of voter-approved bond sales allowed the city to launch a $92 million program in 2011, which further bolstered the fields for the future. The city commissioned the Savik 1 and 2 wells at East Barrow and the Walakpa 11, 12, and 13 wells at Walakpa - the first horizontal drilling campaign ever conducted at the fields.
By improving deliverability, Barrow has been able to use natural gas for its energy needs even during cold snaps or maintenance activities, instead of falling back on diesel fuel.
South and East Barrow
The 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 and drilling continued for decades, with 13 new wells drilled and one 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 demand during peak winter months, which has does not appear to have been necessary for the past few years.
According to the AOGCC, the South Barrow field had produced more than 23.7 billion cubic feet of natural gas at the start of 2014 and cumulative production was unchanged as of June 2016. The field was originally expected to produce as much as 32 bcf.
The U.S. Geological Survey discovered the East Barrow field with the South Barrow No. 12 well in 1974, during the second wave of NPR-A exploration. Production began in December 1981, but drilling continued through 1990, with eight wells altogether. East Barrow production peaked at some 2.75 million cubic feet per day in early 1984.
At the start of 2014, the East Barrow field had produced more than 8.8 bcf of natural gas, according to the Alaska Oil and Gas Conservation Commission. By the start of 2015, production was more than 8.9 bcf. At the start of 2016, cumulative production had increased by some 200 million cubic feet to more than 9.1 bcf, where it more or less remained through the first six months of this year, as temperatures rose.
That figure greatly surpasses an early estimate of 6.2 bcf in place.
The city of Barrow attributes the productivity of East Barrow to methane hydrates - molecules of natural gas trapped inside cages of ice. The gas can be released through pressure changes. Drops in pressure occur naturally during the aging process of a field.
Walakpa
The South Barrow and East Barrow reservoirs are in a stratigraphic setting similar to the Alpine oil field some 135 miles to the east. The third field supplying the city of Barrow, Walakpa, is in the Pebble Shale unit, a major North Slope petroleum source rock.
Today, Walakpa produces the majority of the gas delivered to Barrow.
Working under a Navy contract, Husky Oil discovered Walakpa 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.
At the start of 2014, the Walakpa field had produced more than 25.5 bcf of gas. At the start of 2015, cumulative production had increased approximately 1.4 bcf to more than 26.9 bcf. By the start of this year, cumulative production had increased approximately 1.4 bcf to a total of more than 28.3 bcf. In the first half of 2016, Walakpa produced 800 million cubic feet, suggesting steady rates.
