|
BP plans to test Ugnu production methods
Kristen Nelson Petroleum News
Viscous oil from the Schrader Bluff and West Sak formations represents only some 100 million barrels of cumulative North Slope production to date, compared to 15 billion barrels of light oil.
Some 45,000 barrels per day of viscous oil is in production across the slope — at Milne Point, Prudhoe Bay and Kuparuk — and an additional 100 million to 1 billion barrels of viscous production is possible.
The big prize is going to be tougher to get, Scott Digert, BP’s Milne Point resource manager, told the Alaska House Special Committee on Ways and Means Jan. 31.
That’s the 20 billion barrels in place at Ugnu, the formation containing the shallowest and heaviest of North Slope oils.
While Ugnu is a known resource, “in place below our existing infrastructure,” Digert said there is currently no significant production from the Ugnu.
BP thinks it can see how to get at some 20 percent of it, and is working to make that happen, with a heavy oil technology team in place.
Pilot tests this year “We expect to spend about $25 million in 2007 to do pilot tests for technology we think will be useful for producing this oil,” he said.
The first wells will use a technology called “CHOPS,” cold heavy oil production with sand, where the focus is on producing the oil along with massive amounts of sand that come with it. The sand will be separated on the surface, and the oil will have to be warmed before it can be transported with light oil.
In the future BP hopes to try thermal technologies, Digert said, “probably including steam injection or other thermal recovery methods to warm the oil up and reduce the viscosity and make it flow more easily.”
While BP doesn’t “don’t know how exactly to do it,” at this point, the company is exploring different ways to produce Ugnu heavy oil.
One thing that is known, however, is that it will be more expensive. “By comparison to the light oils, if we’re producing and separating a lot of sand, if we’re generating steam to inject, all those things add cost, it adds complexity; it reduces the economics of the wells themselves.”
Not the same as Alberta Digert said BP would be learning from other heavy oil development areas, such as Alberta, but said there are differences between the North Slope heavy oil resource found in the Ugnu and what is found in Alberta.
Some of the Canadian oil sands “are quite shallow to the point that they actually mine them,” he said, which allows for 100 percent recovery.
The Ugnu is at a depth of about 2,500 to 3,500 feet and below the permafrost, so mining isn’t an option on the North Slope.
Steam injection is also expected to be less effective on the slope, Digert said, because the Ugnu is colder and then there is the challenge of getting steam down through the permafrost without melting the permafrost, and the challenge of warming up the colder oil enough.
And the rock is different in Canada, where the oil sands are “blocky, very massive sands” allowing for easy vertical movement within the sand column. “Ours tend to have layers of shale within the sand that tend to block that vertical movement of oil.”
| 