Endicott field still shows some kick

By Wesley Loy

For Petroleum News

The BP-operated Endicott oil field on Alaska’s North Slope has been producing since 1987.

While the field peaked years ago, the old dog can still hunt.

That’s that sense you get from reading BP’s latest annual progress report and plan of development for the Duck Island unit, which includes the Endicott reservoir.

The document, submitted on May 1 to the state Division of Oil and Gas, surely will be of interest to Hilcorp, the Houston-based independent poised to take over as operator of Endicott as part of a pending deal to purchase a package of North Slope assets from BP.

A well workover program was completed in 2013 in Endicott, BP said, adding that the owners intended to continue monitoring reservoir performance with an eye toward additional drilling opportunities.

Endicott production is based on an artificial island about three miles offshore in the Beaufort Sea. A causeway connects the 45-acre island to the mainland.

BP has called Endicott the first continuously producing offshore field in the Arctic.

Discovered in 1978, the field reached its peak production of 118,000 barrels per day in the early 1990s.

Over their lifetime, Endicott and related pools have produced more than 477 million barrels of crude oil, state figures show.

Endicott’s oil-bearing rocks lie in the Kekiktuk formation, a shale and sandstone formation similar to the Sadlerochit in the giant Prudhoe Bay field nearby. The oil column is about 10,000 feet down.

BP currently owns about 68 percent of Endicott field, with ExxonMobil holding 21 percent and Chevron almost 11 percent.

BP says its average net production from Endicott in 2013 was about 5,000 barrels of oil equivalent per day.

Hilcorp has a reputation for reviving mature fields, and Endicott would seem an ideal challenge for the company.

The Duck Island unit has a number of participating areas including Endicott, Eider and Sag Delta North, plus the Minke tract operations.

BP, in its progress report and plan of development for the coming year, said no drilling activity occurred in the Endicott participating area in 2013.

However, rig workovers were completed on three Endicott wells. And a planned maintenance event took place in 2013 to update water and gas injection systems.

Historically, BP has enhanced oil recovery by injecting water into the Endicott reservoir. It also has used a technique called miscible water-alternating-gas flood.

Engineering studies are under way to evaluate the initiation of gas cap water injection at Endicott, BP’s development plan says.

“The Endicott owners will continue to monitor production trends of oil, gas and water for all producing wells, and maintain reservoir pressure through gas and water injection,” the plan says.

In the Eider participating area, BP in recent years has made significant moves with two wells.

In 2013, the Ivishak formation in the Eider No. 1 well was isolated due to high water cut and perforations were added to begin production from the Sag River formation. In 2009, the Eider No. 2 well was sidetracked to the Minke target.