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More wells at Colville River unit Fiord Eight wells planned for Alpine satellite’s Nechelik reservoir; wells identified as candidates for fracturing; more water injected Kristen Nelson Petroleum News
In an update to its Colville River unit development plan, ConocoPhillips Alaska has told the state that in addition to two remaining wells from its original Fiord Nechelik development plan — both to be drilled in 2009 on the western edge of the Fiord participating area — it plans to add six more wells within the Nechelik reservoir.
Nine wells — four producers and five injectors — have been drilled in the Nechelik reservoir at Fiord, the northern satellite to the Alpine field on the western side of the North Slope. All the wells were long (7,000 to 10,000-plus feet) horizontal wells and one, CD3-109, is a record length, 10,600 feet of horizontal section, for the Colville River unit area.
ConocoPhillips called operations at the Nechelik participating area, developed as a road-less drill site, “challenging but ultimately successful.” The Colville Delta 3 (Fiord) drill site can be reached only by air except during the winter ice road season, which limits drilling and well work to winter months.
In addition to horizontal well technology, ConocoPhillips has used enhanced oil recovery, similar to Alpine, at Fiord Nechelik.
Production began from Fiord Nechelik in August 2006 and in 2007 averaged 9,900 barrels per day; for the first eight months of 2008 production averaged 12,100 bpd. ConocoPhillips estimated that 2009 Fiord Nechelik production will average 12,600 bpd from base production plus 2,200 bpd from new wells planned for 2009.
Original plan nearly complete ConocoPhillips said in September that the original development plan for Fiord Nechelik was nearly complete, with only two remaining wells, both producers, to be drilled in 2009 on the western edge of the Fiord participating area.
Most of the wells were open hole completions in the reservoir, except for two completed with preperforated liners in anticipation of hydraulically fracturing the wells; the two wells from the original plan to be drilled in 2009 will also have preperforated liners.
The company said the main drilling challenges have been drilling out of zone — resulting in sidetracks — and “lost circulation on the eastern side of the field near the Fiord fault system.”
“Reservoir quality on the southern and eastern edge of the Fiord Nechelik PA suggests economic development of those areas is possible,” ConocoPhillips told the state, and as a result six additional wells are planned within the Nechelik reservoir in 2009-11. The company said “reservoir quality is expected to be the biggest challenge as these wells target what is believed to be lower permeability rock.”
Beyond 2011 ConocoPhillips said it “intends to develop additional sands in the southern Nechelik reservoir and also both the Kuparuk and the Nechelik sands in the Fiord West satellite area, located southwest of the current Fiord development.” The company said these longer-term plans “are contingent on obtaining viable permits to cross the Nigliq channel” of the Colville River.
Candidates for fracturing Production began at Fiord Nechelik in August 2006; seawater injection began in mid-September of that year. Miscible injectant was first injected into the Nechelik sand in July 2007; in March 2008, ConocoPhillips began injecting a combination of seawater and produced water.
The company said water availability has been an issue at CD3: Prior to 2008 limited water volumes were available from the seawater treatment plant. In March 2008 ConocoPhillips received temporary approval to inject a mixture of seawater and produced water. The goal of the current water injection program is to achieve a voidage replacement ratio of 1.0 or greater; ConocoPhillips said it “has seen a beneficial production response as a result of this water injection program” with minimal water production from the Nechelik sand and no observed water breakthroughs. “A project team is currently looking into long-term solutions for the water availability issues at CD3,” the company said.
None of the Fiord Nechelik wells have been hydraulically fractured, “but the Fiord team has identified several potential ‘frac’ candidates” for 2009-11.
The revision of the Fiord Nechelik participating area, approved by the state in late October, is based on plans to drill eight wells in the 2009-11 timeframe. ConocoPhillips said the “slight contraction in the southwest corner” of the participating area (in the revision just approved by the state) is not expected to be permanent, as the company plans to drill in the southwest, but “that drilling will likely take place after the next Fiord Nechelik PA redetermination.”
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