Expounding for the first time on the mechanical troubles hinted at earlier in the year, independent TG World Energy on May 15 said coiled tubing stuck in the North Shore No. 1 well prevented testing on one of the two target formations earlier this year.
The exploratory drilling program on Alaska’s North Slope this past winter was run by Brooks Range Petroleum Corp. on behalf of a joint venture with TG World, Nabors subsidiary Ramshorn Investments Inc. and Bow Valley Alaska Corp.
“The coiled tubing became stuck in the hole before a production test could be conducted on the Sag River formation; a zone with approximately 20 feet of oil pay with no water line encountered,” TG World said in a release on May 15.
Hoping to regain full access to the Sag River formation, BRPC attempted a fishing operation from April 22 through May 6 using the Nabors rig 27E.
BRPC recovered a 700-foot portion of tubing from the wellbore, but warmer weather “made it necessary to suspend the well and leave the remaining tubing in the hole,” according to TG World.
BRPC released the Nabors rig from its contract May 7.
With coiled tubing “stuck across the zone of interest, diesel was pumped into the well, which was then opened to flow,” TG World said. “The well flowed for 18 hours at an average rate of 50 barrels per day of diesel cut oil. Pressure transient analysis of the flow test and several step-rate pump-in tests indicate that the 22 foot interval of completion perforations was severely damaged.”
Without that damage to the perforations, BRPC calculated the well would have flowed at “10 to 20 times the actual rate or 500 to 1,000 barrels of oil per day” from the Sag River formation, making the total flow from the Ivishak and the Sag River formations in the neighborhood of 2,592 to 3,092 barrels of oil per day.
“Specific well work to confirm commercial rates” from the well is “being formulated,” TG World said. The company also said development planning work for the North Shore prospect has begun “to determine the optimal recompletion or sidetrack strategy for North Shore No. 1, in the context of an overall commercialization plan.”
The stuck tubing did not prevent the companies from testing the Ivishak formation in the North Shore well, northwest of Prudhoe Bay. The Ivishak formation flowed at a “stable oil flow rate” of 2,092 barrels of oil per day of 34 degree API oil for five hours.
Note: See full story in May 18 issue of Petroleum News, available to subscribers online on Friday, May 16, at www.PetroleumNews.com.