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Testing of Nanushuk reservoirs at Oil Search’s North Slope wells encouraging
The well tests released by Oil Search on March 31 for its North Slope Mitquq and Stirrup prospects were very encouraging, said Keiran Wulff, the company’s managing director. The wells were drilled during this winter’s off-road exploration season.
The results were for the Nanushuk reservoirs encountered in the Mitquq 1 ST1 and the Stirrup 1 exploration wells.
Mitquq 1 ST1, a sidetrack from the Mitquq 1 oil discovery, is 5.6 miles east of the proposed central processing facility of the Pikka unit development west of the central North Slope.
It encountered a net pay zone of 172 feet with a gas cap of 29 feet. On test, the well flowed at a stabilized rate of 1,730 barrels of oil per day from a single stimulated zone.
Oil Search said a high quality oil in a deeper reservoir at Mitquq was also discovered but not tested.
The Stirrup 1 exploration well, approximately 7.5 miles west of the 2017 Horseshoe discovery well and 22 miles southwest of the proposed Pikka development, encountered an oil column with net pay of 75 feet. On test, Stirrup 1 flowed at a stabilized rate of 3,520 bopd from a single stimulated zone.
Flow tests in both wells included a cleanup, flow period and a pressure buildup prior to the final flow test to assess well deliverability.
“The two Mitquq (Mitquq 1 and Mitquq 1 ST1) and Stirrup 1 oil discoveries, together with the Mitquq 1 ST1 and Stirrup well tests, have provided valuable information regarding the geology and well productivity of the Nanushuk play in the areas to the east and south west of the Pikka unit,” Oil Search said.
Increasing reserve estimatesIn addition, the discoveries support the potential for material resource growth.
After last winter’s exploration season Oil Search contracted with Ryder Scott to do an independent assessment that would only assess oil that will be produced under the present Pikka development plan.
Ryder Scott boosted the certified gross 2C contingent recoverable oil from 500 million barrels to 728 million barrels, a 46% increase.
Wulff weighs in“We are very encouraged by the success of our 2019/20 Alaskan exploration program, with oil discovered in all three penetrations, at Mitquq 1, Mitquq 1 ST1 and Stirrup, and excellent flow rates achieved in the two well tests,” Wulff said.
At present, Oil Search does not plan to pursue an exploration drilling program in the 2020/21 winter season. Until oil prices improve it will focus on maintaining capabilities, advancing work needed to comply with permitting obligations and pursuing opportunities to minimize costs and add value to Pikka unit development.
All of this will “enable Oil Search to respond quickly when oil prices improve,” Wulff said.
But the company “remains committed to progressing the Pikka unit development,” he said, which is likely to go online in 2024 and peak at 135,000 bopd.
The company has said that success at the Stirrup prospect could de-risk additional fairways to underpin a possible standalone Horseshoe development, noting Stirrup is a direct analogue to the Horseshoe 1 Nanushuk discovery.
Oil Search has referred to the Mitquq prospect as a “high value tieback” to future Pikka infrastructure.
With testing complete at both well locations, the crews are demobilizing and expected to be off location by mid-April.
In addition, the winter season early civil works program, which has included the construction of ice and gravel roads, gravel pads and a bridge, is expected to be completed shortly, with all crews, equipment and support infrastructure to be demobilized by the end of April.