More results from White Hills wells

Alan Bailey

Petroleum News

Ever since 2008, when Chevron embarked on an ambitious exploration drilling program in the White Hills area, south of Prudhoe Bay on Alaska’s North Slope, the company has remained tight lipped about its findings from its White Hills wells. The company drilled three wells in the area in 2008 and two more in 2009, saying that it was searching for both oil and gas. None of the wells, all named after prehistoric animals, penetrated depths below about 5,000 feet.

In the absence of some overriding need for data confidentiality, the Alaska Oil and Gas Conservation Commission publishes Alaska well data within 25 months of an oil company filing that data with the commission. And, so, some two years after the drilling of Chevron’s 2008 White Hills wells, data for those wells have now become available to the public.

In May Petroleum News reported on the data that had been released for one of those 2008 wells, the Mastodon 3-6-9, saying that the well had targeted natural gas in the Prince Creek, Ugnu and West Sak formations of the Brookian sequence. The target structure was a northwest-southeast trending closure with stratigraphic and dip related traps.

AOGCC has since published the records for the other two 2008 wells, Smilodon 9-4-9 and Panthera 28-6-1. According to shallow hazards reports in the newly released AOGCC records, the two wells were investigating Brookian gas prospects almost identical to those for the Mastodon well.

The Smilodon well reached a measured depth of 5,058 feet and a true vertical depth of 4,959 feet. The Panthera well was drilled vertically to a depth of 2,020 feet, at which point the drilling was terminated following problems with a stuck bottom hole assembly. Both wells were plugged and abandoned.

AOGCC will not release the data for the two wells drilled in 2009, the Bluebuck 6-7-9 and Muskoxen 36-7-8, until 2011.

In February Chevron relinquished 41 of its White Hills leases, comprising approximately the southern two thirds of the company’s acreage in the region. Leases retained included the locations of the 2009 wells. In August the company dropped five more leases in the northern tip of the region.

—A copyrighted oil and gas lease map from Mapmakers Alaska was a research tool used in preparing this story.