Brookian shows promise to east

Kay Cashman

Petroleum News

In a Nov. 2, 2017, presentation in Anchorage, David Houseknecht, a U.S. Geological Survey expert on northern Alaska, said that given the wide spacing between the vintage 2-D seismic lines shot in the ANWR 1002 area in the mid1980s, it would be possible to hide a stratigraphic trap on the scale of Willow or Pikka between the lines. (Both are major Nanushuk oil discoveries that lie west of the central North Slope.)

Houseknecht also said the Brookian sequence shows hydrocarbon potential in the ANWR 1002 area.

In a mid-2018 Petroleum News interview, Paul Decker talked about younger Brookian sediments deposited on the ancient shelf margin in the 1002 area, noting they were analogous to the huge Nanushuk formation discoveries by Armstrong and partner Repsol west of the central North Slope.

Although Nanushuk rocks are not found on the eastern North Slope, Decker said the Nanushuk oil play may prove valuable as a geologic paradigm for oil prospects to the east in the 1002 area.

At the time, Decker was the lead petroleum geologist at Alaska’s Division of Oil and Gas; today he is working for Armstrong and Repsol’s new operating partner, Oil Search.

In addition to the western finds, Armstrong and Oil Search more recently became 50-50 partners in a 195,200-acre block on the eastern North Slope. “We’re trying to continue to make the play that we discovered to the west, the Nanushuk at Pikka,” Armstrong Oil & Gas President and CEO Bill Armstrong told Petroleum News Jan. 30.

“It is a very subtle play; that’s why it has been hidden for so long. … The amount of running room this concept has is just massive in Alaska. ConocoPhillips is chasing it west … but going east from Pikka we also see the same thing. We’re really excited,” he said, not naming the lookalike formation. - KAY CASHMAN