HOME PAGE SUBSCRIPTIONS, Print Editions, Newsletter PRODUCTS READ THE PETROLEUM NEWS ARCHIVE! ADVERTISING INFORMATION EVENTS PETROLEUM NEWS BAKKEN MINING NEWS

Providing coverage of Alaska and northern Canada's oil and gas industry
June 2011

Vol. 16, No. 25 Week of June 19, 2011

Eyeing the possibilities at Kotzebue basin

Consultant, NANA say the Kotzebue basin in northwest Alaska has large prospects and potential for natural gas and possibly oil

Alan Bailey

Petroleum News

Only two wells have ever been drilled in the 80-mile by 350-mile Kotzebue basin, under the Kotzebue Sound and some adjacent lowlands, immediately north of Alaska’s Seward Peninsula. But this remote basin, sometimes referred to as the Selawik basin, has significant potential for the discovery of natural gas, and perhaps oil, according to a presentation by NANA Regional Corp. and Terence Eschner of oil consulting firm Sarlan Resources at the Pacific Section, American Association of Petroleum Geologists, on May 11.

NANA, the Native regional corporation for northwest Alaska owns the mineral rights to the onshore portions of the basin and has leased exploration rights on some of its land to California-based Trio Petroleum, a company that since 2009 has been planning to drill some oil and gas exploration wells in its Kotzebue basin leases.

Cook Inlet comparison

Eschner told the AAPG conference that the basin, about the same size as the Cook Inlet basin in Southcentral Alaska and with somewhat analogous geology, is up to 20,000 feet thick. The basin is filled with sediments of Tertiary and probably Cretaceous age, and contains many large exploration targets, Eschner said. Geologists think that the basin formed as a result of geologic faults wrenching open a depression in the Earth’s crust.

The two wells in the basin, drilled by Standard Oil of California, or Socal, in the 1970s, used onshore locations to test the stratigraphy of the basin’s rock sequence. One of those wells, the Nimiuk well, is located on the Baldwin Peninsula near the town of Kotzebue, while the other is on Cape Espenberg, on the north side of the Seward Peninsula. Both of these stratigraphic test wells demonstrated the presence of rocks conducive to the operation of a petroleum system in the basin, with river-lain sandstones and conglomerates of Tertiary age that could form excellent oil or gas reservoirs; shales and coals that could act as hydrocarbon sources; and shales that could seal hydrocarbons in reservoir rocks, Eschner said.

Oil at depth?

Source rock samples showed good to high organic material content, with kerogens in the material being primarily of a type that would generate natural gas, Eschner said. However, with neither of the wells being drilled in the deepest parts of the basin, there is no rock data available for depths below about 8,000 feet, he said. But projections of the likely subsurface temperatures indicate that the source rocks could be cooked into oil generation at depths between 6,000 and 13,000 feet, he said. That leads to the possibility of biogenic gas, formed from the decomposition of organic material in coal seams, at depths less than 6,000 feet, with gas formed by thermal action, and possibly oil, deeper in the basin, Eschner said.

About 1,500 miles of 2-D seismic data, shot by Socal, coupled with gravity and aeromagnetic data provide insights into the structure of the basin.

And these data sources have revealed about 30 prospects, some of them very large, including major folds in the rock strata, fault blocks and potential hydrocarbon traps formed from the juxtaposition of reservoir and seal rocks.

For example, a prospect near Cape Espenberg consists of a shallow, 70-square-mile dome, and another prospect, called Amaouk Creek, consists of a fold in the rock strata encompassing a 27-square-mile area. This latter prospect is larger than either the huge Beluga River gas field or the North Cook Inlet gas field in the Cook Inlet basin, Eschner said.






Petroleum News - Phone: 1-907 522-9469 - Fax: 1-907 522-9583
[email protected] --- http://www.petroleumnews.com ---
S U B S C R I B E

Copyright Petroleum Newspapers of Alaska, LLC (Petroleum News)(PNA)©2013 All rights reserved. The content of this article and web site may not be copied, replaced, distributed, published, displayed or transferred in any form or by any means except with the prior written permission of Petroleum Newspapers of Alaska, LLC (Petroleum News)(PNA). Copyright infringement is a violation of federal law subject to criminal and civil penalties.