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North Tarn, winter’s only North Slope exploration well, finds oil
A joint venture led by Brooks Range Petroleum Corp. found oil at a North Slope exploration well this year, but won’t be able to fully test the well until next winter.
The companies spud the North Tarn No. 1 well on March 13 from an ice pad two miles west of the Kuparuk River unit and reached a measured depth of 6,223 feet by March 22, deep enough to test reservoir targets in the Brookian and the deeper Kuparuk sandstones.
The companies did not log the Kuparuk sandstones and could not estimate net pay, though, because of “well control challenges,” according to partner TVI Pacific Inc., the Calgary-based independent that acquired TG World Energy Corp. earlier this year.
“Minor gas kicks and oil shows occurred in the shallower Brookian target sandstones but were much lower-permeability than expected. … On penetration of the Kuparuk zone, there were strong mud gas shows with high oil-cut mud and gas flow to surface tanks,” the company said, adding that “a period of well control operations from March 22 until April 2 was required before mud losses and hydrocarbon flows to surface tanks stopped.”
Kuparuk estimated at 20-25 feet Based on sandstone cuttings and gas readings taken from the well, TVI Pacific estimated the Kuparuk to be about 20 to 25 feet thick at North Tarn No. 1. That would be comparable to the thickness of the Kuparuk C1 sandstone in the nearest Kuparuk River well, located 2.4 miles to the east, and the 2L-03 well drilled a mile to the south in 2002.
On April 11, the companies drilled a “substitute well” using the existing surface hole. By April 14, the well reached a measured depth of 6,086 feet, to the base of the Kalubik formation, just above the Kuparuk C sand, and the companies set intermediate casing.
The companies drilled the well using Nabors rig 9ES.
BRPC is operating the program on behalf of its parent company, the Kansas-based Alaska Venture Capital Group LLC, as well as three joint venture companies: Brooks Range Development Corp., Ramshorn Investments Inc. and TVI Pacific.
“Our team is very encouraged by the information obtained from the North Tarn well,” Ken Thompson, managing director of AVCG LLC, said about the results so far.
North Tarn No. 1 was the only exploration well on the North Slope this winter.
The joint venture farmed-in six Eni Petroleum leases at North Tarn in January 2010 and recently applied to form the Southern Miluveach Unit, covering 56,460 acres in the area.
—Eric Lidji
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