ConocoPhillips set new record for North Slope horizontal oil drilling; production on slope holding steady

North Slope production held steady in April compared with March and April of 2021, according to production data released May 1 by Alaska’s Department of Revenue.

The Alpine field, one of three larger fields on the slope, has been restored to normal production after being cut 8,000 barrels per day in January and February as operator ConocoPhillips dealt with an unusual underground gas release.

In another development, ConocoPhillips completed its first long horizontal production well to a new project in the Alpine field, Fiord West. The well was drilled to 35,526 feet, a new record for an Alaska horizontal well.

That distance means the drill rig in the Alpine field has drilled horizontally, or laterally, from the location of the rig to the underground Fiord West deposit.

Meanwhile, overall North Slope production averaged 489,565 barrels per day in April, almost dead even with 483,400 barrels per day in March and 489,303 barrels per day in April 2021, according to the revenue department data.

In year-over-year comparisons, the Prudhoe Bay field, the largest North Slope field that is operated by Hilcorp Energy, averaged 314,831 barrels per day in April 2022 compared with 483,440 barrels per day in April 2021.

Kuparuk River, operated by ConocoPhillips, averaged 104,270 barrels per day in April compared with 113,152 barrels per day in 2021. The Alpine field, also operated by ConocoPhillips, averaged 49,901 b/d in April compared with 48,710 barrels per day in April 2021.

The small Lisburne field operated by Hilcorp averaged 20,563 barrels per day in April compared with 22,350 barrels per day in April 2021. This includes output from the Lisburne reservoir underlying part of the eastern

Prudhoe Bay field but also includes production from several smaller nearby reservoirs such as Endicott, Point McIntyre and Niakuk.

Natural gas condensates from the ExxonMobil-operated Point Thomson field 60 miles east of Prudhoe Bay are transported by pipeline and “cominged” with Lisburne field production and also included in the data for that field.

While North Slope production is holding steady it also continued on a gradual, long-term decline. In April 2019, the last year before the pandemic affected industry worldwide, the North Slope averaged 506,475 b/d.

Prudhoe Bay actually showed an increase from 2019 to 2022, from 297,045 barrels per day in April 2019 to 314,831 in April 2022, the two other larger slope fields showed declines.

Kuparuk River dropped from 122,843 barrels per day in April 2019 to 104,270 barrels per day in April 2022. The Alpine field dropped from 66,151 barrels per day in April 2019 to 49,901 barrels per day in April 2022.

The effects of new production will gradually be felt in the next few months. ConocoPhillips’ new GMT 2 project in the National Petroleum Reserve will be increasing in output through late spring and summer, for example.

In a related development, ConocoPhillips cut Alpine field production at its CD1 drill site as the company dealt with gas release from an undetected below-ground low pressure gas pocket at approximately the 4,000-foot level where gas had migrated to the surface as through gravel on the CD1 production pad.

The company cemented off a section of a water injection well on the pad to stop gas entering the well bore. However, the Alaska Oil and Gas Conservation Commission, a state agency that regulates well safety, reported that minute quantities of gas were still being detected inside well houses on the CD1 production pad.

No gas was being detected outside the well houses, though. ConocoPhillips relocated workers from the pad as a precaution when the gas was detected. No injuries or damage resulted from the release, however, the company said in a statement.

Small gas pockets are not unusual on the North Slope and can be a drilling hazard if they are high-pressure. In other developments, ConocoPhillips has completed the first extended-reach horizontal production well drilled to Fiord West, an undeveloped accumulation in the Alpine field.

“The Fiord West Well drilled to the planned total depth on April 11. The total measured depth of the well is 35,526 feet measured depth making it the longest North American land based well (a record that was previously held by a CD5 well). We are currently running completions in the well,” ConocoPhillips spokesperson Rebecca Boys said in a May 3 statement.

ConocoPhillips used a specialty-built heavy drill rig, Rig 26 operated by Doyon Drilling Co., for the project.

Technical difficulties in drilling the well were encountered that resulted in a delay in completion, according to sources familiar with the project. Drilling on the well started in second quarter 2021.

Additional horizontal wells are planned, but ConocoPhillips told state officials in filings that it will do pilot test wells to assess subsurface conditions for planning of the added wells.

The first well will also be used as an injector rather than for production as had been initially planned, state officials were told. This means that a startup of Fiord West might await the additional drilling. ConocoPhillips has estimated that Fiord West will produce 20,000 b/d when fully online.

The company has had good luck in drilling long horizontal wells elsewhere on the slope, particularly at the CD5 drillsite adjacent to the Alpine field, but localized geological conditions can create problems in drilling these complex wells, according to sources.

For example, Eni Oil and Gas has encountered technical difficulties in drilling and completing its North Nikaitchuq exploration well, a long horizontal well drilled to test potential offshore producing reservoirs in federal Outer Continental Shelf waters north of State of Alaska submerged lands along the coast.

Eni operates the small Nikaitchuq and Oooguruk fields in coastal waters north of the Kuparuk River field.