Recovering stranded bitumen

There is a way to access stranded bitumen resources while at the same time improving reclamation performance — that’s what mining engineer Howard Keele would like to prove with a conceptual technology called convergent bitumen recovery (CBR). He calls it convergent because it is a joining together of principles from the coal and oilsands mining industries.

Keele graduated from Queen’s University in Kingston, Ont., in 1980. He worked in the coal industry until 1990, when he moved to Fort McMurray, Alta., joining Suncor. Since 2000, he has been working as an independent mining consultant, and it has been during this time that he came up with CBR.

“Sometimes, and not just in the oilsands industry, we do not take a step back and look at the bigger picture,” Keele says, adding that even so, there have been tremendous breakthroughs in the oilsands industry, such as the advent of hydrotransport. “I know for a fact that the employees of these large oilsands companies are working extremely hard to complete their assigned duties on time and on budget, correctly. I took a break from that pace and had a chance to look at the big picture. The CBR process is a result of that stepout thinking, some would say dreaming.”

The CBR process works like this: first — as in surface mining — muskeg and overburden is removed, daylighting the bitumen deposit. Blast holes are drilled and explosives are detonated at three levels.

“We end up with a blasted deposit,” Keele explains, adding the concept has similarities to the use of hydraulic fracturing in conventional oil and gas.

Next, a decant system is built around the area using the overburden to control fluids. Both vertical and horizontal wells are drilled into the formation, and a combination of hot water and compressed air is injected. Keele says that the use of these two injectants alone provides value.

“One of the key objectives of the CBR process is to eliminate the use of any chemicals. We want to wash the sand in place, push the temperature of the bitumen so that it becomes lighter than water, and then float the bitumen to the surface using compressed air, much like is done in a process separation vessel.”

The bitumen froth would then be decanted into a radiantly heated decant tank, and sent for further cleaning. Recycled hot water and tank bottoms would be sent back into the formation.

“Further upgrading will move it from a bitumen to a sweet synthetic crude oil, much like that which is produced by the operating plants now,” Keele explains.

Total volume to bitumen in place (TV:BIP) is a relatively simple concept, but one that is of key importance to the economics of an oilsands mine.TV:BIP determines how much material must be moved to achieve a certain level of recovery. The less material that has to be moved, the better — as the TV:BIP ratio increases, the economics erode in step.

Currently, the Alberta Energy and Utilities Board (EUB) has set the maximum TV:BIP ratio at 12. However, there is much land in the Athabasca region with bitumen in place that is shallow enough to be mined, but its TV:BIP is considered too high. As well, there are areas with TV:BIP of less than 12, but these “orphan” deposits are considered too small to be commercially recoverable.

Beyond TV:BIP, there is a “grey area” where bitumen is too deep for surface mining but too shallow for in situ technologies.

“The CBR process could tackle a large portion of these areas at about the same cost as the present surface mining operations are incurring,” Keele says. “In essence, the extraction plant has been moved to the field, and the loading, hauling, crushing, conveying, hydrotransport, as well as most of the tailings work functions have been eliminated.”

The technology is designed to supplement and not replace current methods, producing in the range of 20,000-30,000 barrels per day. However, Keele notes that the optimal size of a CBR operation has not yet been determined.

Keele says that one of the key benefits of the CBR process is its reclamation strategy, aimed to be achieved within 10 years of bitumen depletion. He says that the first oilsands tailings pond has yet to be reclaimed, a full 40 years after it was made. Knowledge and experience from the coal strip mining industry has helped Keele come up with the CBR process.

“Arguably, the best reclamation in the mining industry today is that done by the coal strip mining industry (less than ten years). It is so well organized, and that is what we are trying to emulate here.”

In the end, CBR would leave the sand in place, with the overburden and muskeg replaced above the depleted deposit.

Right now, CBR is a conceptual process. However, Keele says the last two years have been fruitful. Its patent is pending, and four individuals have put up the money to move it further along the road to commercialization. To date, bench-scale testing has been completed, peer group brainstorming has been conducted (which resulted in some questions, but no fatal flaws detected), an energy balance has been conducted by Hatch Energy (estimating that CBR will take 30-50% of the energy required for today’s mining and in situ operations), field test design engineering and costing has been completed, and confidentiality agreements have been signed with several companies.

The path forward: “CBR must complete a field test to confirm a number of the theoretical assumptions of the process. Recovery, energy balance, and material balances are among the most important,” Keele says. “The present direction is to seek government- assisted funding along with support from an industry partner/ sponsor.” This article originally appeared in the Oilsands Review (www.oilsandsreview.com). The author is the editor of the magazine and can be reached at djaremko@junewarren.com.