The Kuparuk River field has been in production for more than 25 years, since Dec. 13, 1981.
It has a lot more anniversaries to go.
“We don’t feel we’re halfway through the field’s life yet, even though we’re at the 25-year anniversary,” says Paul Dubuisson, manager of North Slope operations for ConocoPhillips Alaska.
Jim Bowles, president of ConocoPhillips Alaska, said: “Today the field continues to be an important legacy asset to our company.”
“Kuparuk has played a key role in the development of ConocoPhillips’ technology in many areas,” Bowles said. “Our key to long-term growth at Greater Kuparuk will be found in the development of the heavy and viscous oils found at West Sak and the Ugnu.”
Georg Storaker, ConocoPhillips Alaska vice president of operations and development, said “Kuparuk is far from retirement.”
“Leadership in innovation and expanding the use of today’s technology could lead to the redevelopment of the Kuparuk ‘A’ Sands using coiled tubing and extended reach drilling technologies.
“There are more opportunities on the horizon,” Storaker said.
Kuparuk continues to expand
“Like most large fields it continues to expand,” Dubuisson said. There’s “a lot of potential” in both the West Sak viscous oil and the older, more conventional reservoirs at Kuparuk. Technology has unlocked “a tremendous amount — but there’s even more there.”
That future lies in two areas, Dubuisson said: infill drilling and enhanced oil recovery in the existing Kuparuk production conventional oil production.
Three-D seismic shot at the field two winters ago allowed the company to identify “quite a bit” of development potential in the existing field, he said, places where the waterflood and enhanced oil recovery project can be fine tuned, based on “knowing more about the geology from the 3-D seismic.”
The 3-D also identified more than 100 infill locations which can be drilled over the next four or five years, some of that around satellites.
The other area is heavy oil, with billions of barrels of West Sak and Ugnu known, because ConocoPhillips drills through those shallower accommodations to reach Kuparuk oil.
Van Lineberger, ConocoPhillips’ Greater Kuparuk operations manager, said that in addition to two Doyon rigs, there are two Nordic rigs at Kuparuk. One of the Nordic rigs is “coiled tubing drilling” capable, another “new emerging technology which really helps us exploit the reservoir,” he said. Coiled tubing allows the company to “relatively inexpensively, very quickly go in and take advantage of some of the new seismic results and further develop the Kuparuk field,” Lineberger said.
More water injection will probably be required at Kuparuk because with declining oil production “the total fluid production tends to go up because of the water you produce along with the oil,” Dubuisson said.
“So I think we’ll probably be installing additional water injection capacity over time.” Additional power will probably also be needed in Kuparuk’s existing facilities over time.
Viscous development ‘well into the future’
But the long-term future at Kuparuk is the West Sak formation.
“Obviously the big development, well into the future, is the … viscous oil.”
West Sak development is under way at Kuparuk, and that development could move “further up in the West Sak to the shallower, colder oils.” Above West Sak lies Ugnu, which is heavier still, and Dubuisson said a lot of technology needs to be developed to produce Ugnu, “but certainly you can envision it in the future,” although there is no timetable for Ugnu.
“We’re working the technologies now. … You have to do a lot of work to decide how it would be possible to produce it.”
But at West Sak the change has been dramatic.
“We brought on another well yesterday (Dec. 10) making about 3,000 barrels a day. … It wasn’t that long ago it would have been a couple hundred barrels a day.”
Lineberger was working for Conoco at Milne Point in the early 1990s, when they were just starting to develop the West Sak equivalent, Schrader Bluff.
“And if we had a 500-barrel-a-day well, we were ecstatic,” Lineberger said. “Today, 5,000 barrels a day is not uncommon for some of the initial rates we get from these tri-lateral West Sak wells.” Technologies such as horizontal drilling, multi-lateral drilling and learning to manage solids have pushed us toward a great future in West Sak, he said.
ConocoPhillips has two rigs working on the 1-J pad right now, Dubuisson said, Doyon 15 and 141.
Pad 1-J is the new pad focused on West Sak production, he said. Pad 1-E, with a lot of Kuparuk production, is also part of overall West Sak development, while 1-J is essentially a “fully dedicated West Sak drill site.”
Sand management good
Sand production has been one of the problems with West Sak and similar reservoirs because they are shallower, softer sandstones, not as well consolidated as deeper formations. When the oil is produced, a lot of sand comes with it.
Dubuisson said he was with Conoco before the Milne Point field was sold to BP. He wasn’t working on Milne, but was in Houston when the company started developing the Schrader Bluff formation there some 15 years ago.
“And they told me that they were producing a lot of sand from these wells. I said that’s impossible — you can’t produce that for very long.”
“We’ve gotten very good at managing it,” Dubuisson said. “The wells produce some sand initially when you bring them on, but as you clean them up, the way we’ve evolved cleaning up the wells, it goes back to just a very small background level.”
Initially there is a good deal of sand production, he said. The laterals on the wells “are so long, because you’re exposing so much of the reservoir … as you clean those out from the drilling process you get a good bit of sand back.”
ConocoPhillips has installed facilities to clean the sand out of the separators, the equipment that separates the oil from the water and gas produced with it. “We can clean out the separators from the sand we see there … while we’re producing.”
That’s been a learning process over the last two years. Initially “we’d bring a new well on and would see large amounts of sand … for a short period of time; and here lately it’s a one- or two-day event.”
Lineberger said ConocoPhillips has “been able to handle the solids that are associated with the West Sak production with minimal production impacts. … And we’re continuing to look at technologies that will make life better,” he said, such as hydro-cyclones and centrifuges, which provide “an enhanced separation process which helps separate oil, water and solids.”
Facilities operation key
The facilities, however, were designed for light oil.
It’s “a testament to the quality of the folks you have there,” Dubuisson said: “They’ve taken facilities that were designed for light oil, and we’ve made some modification, but really it’s been in the way they operate them that they’re able to handle that viscous oil without really any significant difficulty.”
Lineberger said ConocoPhillips is negotiating commercial agreements with some third parties — Pioneer, Anadarko — “to utilize available capacity within our infrastructure, which is good for everybody.”
Major facilities at Kuparuk include three central processing facilities, the seawater treatment plant, pipelines and pads.
47 active drill sites, 2.2 billion in production
There are 47 active drill sites and approximately 1,100 wells at Kuparuk, about half producers and half injection wells, Dubuisson said.
Alaska Oil and Gas Conservation Commission records show that, through the end of November 2006, Kuparuk has produced almost 2.2 billion barrels of oil: 2.1 billion barrels from the Kuparuk River pool; 79.1 million barrels from Tarn; 25.9 million barrels from West Sak; 12.6 million barrels from Tabasco; 11.1 million barrels from Meltwater; and 1,606 barrels from Ugnu.
The Alaska Division of Oil and Gas lists five participating areas in the Kuparuk River unit: Kuparuk, the main producing formation at the field, was discovered in 1969 and produces from the lower Cretaceous Kuparuk formation at about 5,600 feet subsea.
West Sak, discovered in 1971, produces from the upper Cretaceous West Sak Sands at about 3,500 feet subsea.
Tabasco, discovered in 1986, produces from the middle Cretaceous Nanushuk Group Tabasco Sand at approximately 3,000 feet subsea.
Tarn, discovered in 1991, produces from the middle Cretaceous Seabee formation Bermuda Sand at 4,376 to 5,990 feet.
Meltwater, discovered in 2000, produces from the middle Cretaceous Seabee formation Bermuda/Cairn Sands.
Another discovery, Palm, made in 2001, is a Kuparuk C4 interval found to be in communication with the main Kuparuk reservoir and developed from a new Kuparuk pad, 3-S, which came online in November 2003.
Core area working interest owners at Kuparuk are ConocoPhillips, 52.12468 percent; BP Exploration, 37.02472 percent; ExxonMobil 5.8 percent; and Unocal 4.9506 percent.
