Oilweek - March 2008

Nothing but blue sky

A deal with Duvernay Oil Corporation last year may prove strategically significant for Petrobank Energy and Resources Ltd. because it cemented its plans to forge partnerships using proprietary THAI (toe-to-heel air injection) technology. This potential step change in situ enhanced recovery technology is currently still in the pilot stage in the oilsands, but now, with Duvernay’s help, it will be tested in a conventional Bluesky-Gething heavy oil reservoir.

“[The deal] also gets us into a more conventional-type heavy oil area,” says Chris Bloom, Petrobank’s vice-president of heavy oil. Bluesky production is currently being cold produced (without thermal enhanced oil recovery methods).

In fact, Bloomer thinks THAI is actually a better fit for the Bluesky reservoir than its current Athabasca oilsands reservoir near Conklin. Since the oil is already mobile, the process may not need the initial steam to mobilize the crude.

“That’s a big benefit potentially. The process that we have doesn’t use water, it doesn’t use gas, it has lower CO2 emissions, so we’re just drilling wells. We have a much smaller project footprint than other thermal type processes.” It is on the strength of these efficiencies that Petrobank is currently stating its case to regulators that it should be treated more like conventional heavy oil development than a megaproject—especially when it is in the pilot stage. Pending regulatory approvals, a Bluesky pilot may get underway in 2008.

While some companies in the Peace River Arch are getting higher recoveries depending on the geological productivity, the recovery rates at Duvernay’s Bluesky properties are between 6 and 10 per cent of the oil in place. Bloomer claims THAI could turn that into 70 or 80 per cent.

While this is a lofty goal, Canadian Heavy Oil Association president Bill McFarlane says in situ combustion has worked in light and medium oil as far back as the early 1960s.

“With some demonstration and piloting in conventional heavy oil, we’ll see a lot more in situ combustion,” he says. “The natural evolution will be to broadly apply it into the into heavy oils and oilsands.”

Waterflooding is the workhorse of the oil industry, but in western Canada’s heavy oil fields, this bronco is still saddle shy. The Saskatchewan Research Council says eight waterflood projects in the heavy oil region of Lloydminster have been abandoned over the past few decades.

“There’s also a lot of waterflooding of heavy oils in Saskatchewan but not much research being done. Nobody really understands why it works with heavy oil, so we’re doing a couple projects in that area,” says Doug Soveran, manager of production and processing at the SRC.

Soveran says some early heavy oil waterfloods were born out of the need to dispose of a lot of produced water. Reinjecting the water into the formation effectively turned these into waterflood projects. In some cases, it improved recoveries. But several attempts to use heavy oil water flooding on a widespread basis also met with failure. So companies took a step back and engaged SRC to better understand heavy oil EOR.

Now into its third year of research, the SRC uses multivariate statistical methods to understand the factors behind different waterflood EOR results. Some of these include reservoir and operating parameters and the configuration of horizontal injection and production wells.

One interesting SRC finding is that heavy oil is much more sensitive to how the waterflood is implemented and operated.

“When they first started using waterflooding in heavy oil, they would usually convert their lowest producer into an injection well. However, that’s usually a recipe for disaster,” Soveran says. “If it’s a low producer in heavy oil, it usually also makes a really crappy injector as well.”

So a successful waterflood, according to Soveran, requires drilling a new well in a productive area of the reservoir. “This apples to horizontal injectors as well, which can actually be successful as well.”

The full results from the first two years of SRC’s work have recently been released. The most current year’s results are still being compiled. “We’re now in the third year, and we’re not to go much further in this program,” he says.

z

Heavy Oil Facts

GET TING TO MARKET

The marketing of heavy oil is always a challenge, particularly in remote areas. But over the next few years, Bill McFarlane, president of the Canadian Heavy Oil Association, sees this aspect of the heavy oil business improving.

“The fact that there’s a lot more focus on building refining capacity in Alberta [for the oilsands] will also benefit conventional heavy oil,” he says.

VAPEX

Waterflooding is actually only one of three of the research council’s heavy oil focuses: its primary focus is solvent vapour extraction EOR—commonly referred to under the VAPEX umbrella—and a third area that it looks at is a combination of EOR processes, usually involving immiscible gas.

CHOA’s McFarlane notes that energizing heavy oil formations with propane and butane, and in some cases CO₂, is coming into favour with the industry in general. “It’s taking advantage of these reservoirs that have been produced cold. So now you have all these highly altered reservoirs and they’re looking at ways to capitalize on that.”