Delta drilling: Arco and others look to the North Slope's Colville Delta to provide the oil to keep the pipeline flowing.

• Author: Tyson, Ray
• Position: Atlantic Richfield Co.

The central North Slope is a beehive of drilling activity this winter, confirming industry's growing interest in the region. In the Colville Delta, in particular, recent oil discoveries have raised the hope of uncovering enough oil to help stem the tide of declining Alaska production.

While it's unlikely the Colville Delta holds a giant reservoir, its close proximity to existing facilities at Kuparuk, the country's second largest producing field, means even several small discoveries in the area could justify the high cost of developing oil fields in the Alaska Arctic.

Arco Alaska, the operator and largest shareholder in the 300,000-plus barrel-a-day Kuparuk field, is investing a considerable amount of time and money in the Colville. Along with fellow lease holders Union Texas Petroleum and Amerada Hess, it formed the 90,000-acre Kuupik Exploration Unit to expedite the search for crude oil.

Based on the large number of exploratory wells that have been drilled and are being drilled in the Colville Delta, industry observers believe a commercial discovery may be in the offing.

Arco and its Kuupik partners should have a better idea of the delta's oil potential after analyzing results from a three-well program being conducted this winter. The drilling was spurred by two non-commercial discoveries announced by Arco last December.

Fiord No. 1 and Kalubik No. 1, drilled a year ago, each tested productive from two intervals. The depths of the oil zones were not released, but Fiord was drilled to a total depth of 10,300 feet and Kalubik to a depth of 8,300 feet. Peak flow tests ranged from 1,065 barrels a day in Fiord to 1,200 barrels a day in Kalubik -- about the same rate generated by producing wells in the Kuparuk field, located roughly 10 miles east of Arco's Kuukpik Exploration Unit.

"We're looking for sufficient reserves to justify putting in a central processing facility west of Kuparuk," explains Jim Davis, Arco's senior vice president for Exploration and Land. He adds, "These (new) wells will help in evaluating the potential of the area and lead to a better understanding of previous drilling."

Subtle Plays

Although Arco is leading the current charge on the Colville Delta, it is not the first oil company to have tested its subsurface geological features. In fact, various companies have drilled more than 10 exploratory wells in the region since the early 1960s. In 1985, Texaco announced the first Colville discovery in what's now the...