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Kuparuk remains a formidable Alaska field ConocoPhillips reviews past year’s accomplishments, lays out upcoming plans; cumulative production tops 2.5 billion barrels Wesley Loy For Petroleum News
The Kuparuk River unit is Alaska’s second most productive oil field, and operator ConocoPhillips Alaska Inc. is working through many challenges to sustain its output.
The company detailed its efforts in recent updated plans of development submitted to the state Department of Natural Resources.
One major issue is management of Kuparuk’s limited natural gas reserves. ConocoPhillips plans to start importing gas from Kuparuk’s big brother to the east, the Prudhoe Bay unit, as soon as 2014. The imported gas will be used to fuel Kuparuk field operations, freeing up Kuparuk gas for injection back underground to enhance oil recovery.
Kuparuk had produced about 2.51 billion barrels of crude oil through May, Alaska Oil and Gas Conservation Commission figures show. This total includes about 2.3 billion barrels from the main Kuparuk River pool, with the rest from satellite pools including West Sak, Tarn, Tabasco, Meltwater and Ugnu.
The updated development plans ConocoPhillips submitted to DNR’s Division of Oil and Gas on June 27 review accomplishments during 2012, and discuss upcoming maintenance, drilling other operations.
The Kuparuk field Discovered in 1969, Kuparuk began production in 1981 and hit a peak rate of 322,000 barrels per day in 1992.
The producing reservoir is composed of Cretaceous-age Kuparuk sands at depths of 5,500 to 6,500 feet.
Processed oil from Kuparuk is piped 28 miles to Pump Station 1 of the trans-Alaska pipeline.
The Kuparuk field produced an average of 87,900 barrels of oil per day gross in 2012, and the satellites added another 25,200 barrels per day, ConocoPhillips said.
ConocoPhillips, as operator, owns the largest share of Kuparuk at about 55 percent. The next largest owner is BP at about 39 percent, with Chevron and ExxonMobil each holding small stakes.
The Kuparuk field is developed from 44 drill sites, and in 2012 had 821 active wells, including 462 producers and 359 injectors that send water or gas below ground to maintain reservoir pressure and boost oil production.
Among significant accomplishments cited for 2012, ConocoPhillips said it implemented a 14-well coiled tubing drilling, CTD, program that generated a peak incremental oil rate of about 5,050 barrels of oil per day gross.
“Fifty-three laterals were drilled and completed in these wells,” the company’s Kuparuk update said.
Drilling and investment Also in 2012, ConocoPhillips said it executed a workover program that added about 1,350 barrels of oil per day. And non-rig well work including slickline, electric line and service coiled tubing jobs added about 9,500 barrels per day.
The development drilling strategy for Kuparuk going forward is to target high-value locations and to apply the appropriate well construction and completion technologies to reduce costs, ConocoPhillips said.
“Existing wells that are currently shut-in due to mechanical problems or low production rates may be sidetracked to new bottom-hole locations,” the company said. “As the field matures, horizontal, multilateral and CTD sidetrack technologies will play an increasing role in Kuparuk in order to access incremental reserves at reduced cost.”
Analysis of 3-D seismic data has revealed a significant number of leads for infill or sidetrack drilling, ConocoPhillips said.
To tackle the “large portfolio” of CTD candidates, the company said it commissioned and contracted a CTD rig that’s been drilling wells continually since May 2009. Nabors Alaska owns and operates the rig, known as CDR2-AC.
For the coming year, ConocoPhillips is planning 13 to 17 CTD sidetrack projects and one to three new rotary wells.
In terms of exploratory and appraisal drilling, ConocoPhillips on Jan. 18, 2012, spud the Shark Tooth No. 1 well on lease ADL 25603. The rig was released a month later.
“Well results have been evaluated and engineering studies support the development of a new drill site,” ConocoPhillips said. “Permits for construction and operation of this drill site have been submitted to the agencies. Work on funding this project is still ongoing with co-owners.”
On the maintenance front, ConocoPhillips said it faces considerable expense to replace pipelines or convert them to other uses. For example, a 14-mile seawater pipeline, 30 inches in diameter, is slated for replacement in 2014.
The company said it has seen good results so far from an “in-situ coating pilot project” that could prove an alternative to pipeline replacements.
The satellites The most productive of Kuparuk’s satellite fields is West Sak, a shallow viscous oil deposit overlying the Kuparuk reservoir. Discovered in 1971, West Sak’s core area contains a huge prize of some 1.5 billion barrels of oil, but the oil is cold, thick and difficult to produce.
In 2012, West Sak produced an average of 14,185 barrels of oil per day, ConocoPhillips said.
Over its lifetime, the field has produced more than 65 million barrels of crude, state records show.
West Sak had 102 active wells, including 49 producers and 53 injectors, on six drill sites during 2012.
Waterflooding the reservoir for pressure maintenance and improved sweep is the main enhanced recovery technique in West Sak, ConocoPhillips said. The company reports positive results from a pilot project known as “viscosity reducing water alternating gas.”
Over the years, ConocoPhillips has tried an array of well designs to try to unlock West Sak’s heavy oil, including sophisticated horizontal wells with multiple laterals and features to control sand.
“The pace of future West Sak development has slowed while performance of recent developments is evaluated,” the company told the state.
The drilling of five horizontal multilateral producers and 13 vertical injectors on an existing pad is under consideration for a development project known as Eastern NEWS, ConocoPhillips said.
“This would require a pad extension and additional facilities but take advantage of existing infrastructure,” the company said. “Ongoing planning work will continue in 2013.”
After West Sak, the next most productive satellite field is Tarn, located southwest of Kuparuk. The field averaged 7,100 barrels of oil per day in 2012.
Tarn came online in 1998, and has produced more than 108 million barrels of crude so far, state figures show.
“Recent studies have indicated that there may be additional infill and peripheral development opportunities,” ConocoPhillips said in its Tarn update. “Plans for 2013 and 2014 include three grassroots rotary wells and one rotary sidetrack.”
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