ConocoPhillips set a long-distance drilling record in Alaska with a 5-mile well at its CD5 field, where oil production has beat the original target by 25 percent, the company announced Thursday.
In October, the field on Alaska Native land began producing the first oil from within the National Petroleum Reserve-Alaska.
The company said it was producing 20,000 barrels of oil daily at CD5, more than the original production target of 16,000 barrels.
ConocoPhillips had previously said production at the site was exceeding expectations, but did not provide specific details.
In May, the company announced plans to expand the site by drilling additional wells. First oil from the additional drilling is expected to begin flowing in the third quarter of 2017, the company said.
The new drilling record — a horizontal injection well extending 26,196 feet — ekes past the old record by about 100 feet.
The previous holder was a 26,090-foot-well drilled by BP in 2009 at the Northstar field, said Steve Moothart, a petroleum geologist for Alaska Division of Oil and Gas.
The longer wells allow companies to access more oil from a smaller pad on the surface. Moothart said they reduce the need for multiple vertical wells that require the construction of larger gravel pads on the tundra to support drilling rigs and other facilities.
The Alpine unit, home to CD5, began producing oil in 2000. It was the first North Slope unit developed exclusively with horizontal wells.
Drilling technology had reached a point where that was possible, said Moothart.
"Alpine was created as a roadless development," Moothart said. "They were purposely trying to keep the pad size down."
The technology allows workers to steer the drill bit to maximize oil production from a reservoir, he said.
The record well, drilled by Doyon Rig 19, reached a depth of 7,400 feet, with a horizontal leg extending a little more than 3 miles. The well took 24 days to drill.
The longer wells can ultimately mean more oil production over longer periods, while reducing impacts to the environment, ConocoPhillips officials said in a statement announcing the record. More than 60 square miles of subsurface area can be reached from a single drilling pad.
Such wells, while more expensive than shorter, vertical wells, can be more cost-effective because fewer of them can tap greater portions of a reservoir.
The Alpine unit has been an overachiever since its early days. It was designed to produce 80,000 barrels of oil daily, but in part with help from horizontal drilling, the field reached a production high of 139,000 barrels in 2007.
The unit is owned 78 percent by ConocoPhillips, with a subsidiary of Anadarko Petroleum Corp. owning the rest.