Encouraged By Chevron, Partnered With GE, Acceleware Advances Microwave Heating In Reservoir

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In September 1948, a Union Oil Company employee named Harold Ritchey applied for a patent for his method of using microwaves to heat an oil reservoir to enhance production. Eight years later he got the patent.

According to a 2013 review of attempts to use radio frequencies to heat heavy oil and bitumen, Ritchey was the first to come up with a way to use microwave heating to enhance oil production. He certainly wasn’t the last.

In the intervening decades, various attempts have been made to use electromagnetic heating to reduce heavy oil and bitumen viscosity. So far, none of the efforts — including an early field trial in Russia in 1969 — led to large-scale commercial deployment. But industry interest continues. Since 2011, a consortium that includes Suncor Energy Inc. has been intermittently testing the use of radio-frequency (RF) heating with solvents in the Alberta oilsands.

“We’re continuing to work with our partners to complete the Dover pilot and scale up the technology for potential commercial implementation,” Erin Rees, a Suncor spokeswoman, said in an email. “I’d reiterate that it takes time to conduct pilot testing and research.”

The Suncor consortium’s process uses RF energy to heat the reservoir and injects a light hydrocarbon solvent to mobilize and recover the bitumen.

In 2018 — 70 years after Ritchey applied for his patent — a small Calgary tech company is gearing up to test its RF heating technology, which it calls RF XL, in the Alberta oilsands. Acceleware Ltd. has $10 million in federal and provincial funding for a commercial-scale test and is currently in the process of choosing an oilsands partner.

So what’s behind this 70-year quest to put what amounts to an inside-out microwave oven in the reservoir?

It’s the size of the prize. Cutting the capital and operating cost of producing oil that’s too viscous to flow on its own would greatly increase the portion of the world’s heavy oil and bitumen resources that are economically recoverable.

With Alberta’s oilsands sector under pressure from light oil plays that can be developed one well at a time, it’s more important than ever to find a cheaper way to produce bitumen.

SAGD, the most widely used in-situ oilsands technology, requires a steam plant and elaborate water-treatment infrastructure. To avoid fouling steam generators, boiler feed water must go through a complicated purification process.

RF heating would involve RF generators and electricity costs, but wouldn’t involve the huge capital and operating costs of steam generators and water treatment plants. Water handling has been described as the single biggest component of the capital cost of a SAGD project.

And then there’s the inefficiency of transporting steam to a reservoir and the amount of energy wasted. Part of the rationale for RF heating, if it works, is that it would more effectively target the reservoir portions that need to be heated.

How it works

Like SAGD, RF XL would use two parallel horizontal wells. But instead of a steam injector, the upper well would be the heater well containing the RF antenna. Like SAGD, the lower well would produce oil.

The idea is to use microwave energy to convert water already in the reservoir to steam. From that point on, the goal is the same as SAGD — melt the semisolid bitumen so it will flow to production wells.

Like a microwave oven, RF in the reservoir is looking for substances that absorb the energy. Water is one of the best.

“Water, when it's in a liquid phase, absorbs the energy. And when it's in a steam phase, it doesn’t,” explains Geoff Clark, Acceleware’s CEO. “So once the water molecules are converted to steam, then they conduct that heat to the oil and the surrounding rock.”

In other words, once water is converted to steam, “the energy goes further because there’s nothing to absorb it. It keeps going further. That's the inherent efficiency of the system,” he says.


Why Acceleware thinks it can succeed

All this sounds good on paper. But if no one has managed to commercialize RF heating after 70 years, why does Acceleware think it can do it?

“It is a bit of a Holy Grail that has been out there for a while,” concedes Clark.

However, he says Acceleware’s simulation software has been able to determine why previous experiments failed.

Clark says previous efforts were based on radio technology used for communications, which Acceleware says doesn’t work as efficiently underground. “We're talking about generation efficiencies of 65 to 70 per cent instead of 95 per cent the way we've done it,” he says.

Acceleware’s conclusions about communications-based RF technology are based on its own testing of such technology.

“We realized during that test that efficiency was going to be a problem — both in the electronics themselves and in getting that RF energy down into the reservoir,” the CEO recalls.

The communications-based RF technology is also more expensive, says Mike Tourigny, Acceleware’s vice-president of RF heating commercialization. “Those communications RF generators are designed to do a really, really good job at communicating a pure signal. Our clients don't need to invest in that perfect signal to heat water in the ground.”

In other words, if all you’re doing is heating a reservoir, you can generate a very “dirty” signal, but that doesn’t matter as long as it's cheap and efficient.

GE’s silicon carbide semiconductor

So instead of relying on communications-based RF technology, Acceleware partnered with General Electric Company to use GE’s silicon carbide semiconductor. Acceleware believes using the GE platform will increase efficiency to as much as 97 per cent versus the roughly 70 per cent Acceleware says is typical of communications-based RF generators.

Encyclopaedia Britannica describes silicon carbide as a promising substitute for traditional semiconductors such as silicon in high-temperature applications. Companies such as Mitsubishi Electric Corporation and Toshiba have also announced applications for silicon carbide power semiconductors.

For its part, GE claims silicon carbide power devices “are poised to take over for the silicon-based chips that are currently used in the majority of applications that convert and use electricity.” GE’s power group uses silicon carbide semiconductors to convert power to the grid from sources such as wind and solar.

Clark says Acceleware’s partnership with GE is strictly a technology development arrangement where GE is helping Acceleware to adapt the silicon carbide semiconductor to RF heating generators.

Adapting cheaper technology is also a way to cut capital costs. For example, if an RF generator costs $7 per watt and produces four megawatts, that’s $28 million per well — just for the RF generator.

“We needed a technology that was under $1 a watt,” Clark says. “And that's the other thing that led us to GE  — this technology is also much cheaper to produce than the high-fidelity electronics that are in [a communications-based] RF generator.”

Getting through ‘Death Valley’

But possibly the biggest breakthrough for Acceleware’s RF heating, if it works as intended, would be the ability to do one well at a time.

That would presumably remove one of the biggest obstacles to commercialization of new oilsands technologies — the so-called “death valley” syndrome. New technologies that show strong promise after successful research and field testing often don’t achieve full-scale commercial development.

Even when oil was $100 a bbl, few oilsands producers were willing to risk billions of dollars on a 30,000-bbl/d deployment of a new process that’s never been tested at that scale.

Acceleware argues the ability to deploy its RF heating one well at a time would carry it through “death valley” by eliminating the capital risk. Producers could start small and scale up.

“You could essentially build this out with minimal capital investment — something as little as $10 million — and generate some cash flow,” says Clark.

Adds Tourigny: “We believe we can operate with an entirely pad-based infrastructure with production and storage tanks at the pad, along with the RF generators and water separation.”

Making oilsands more competitive

Acceleware says its goal is to make the oilsands more competitive in terms of capital costs, operating costs and greenhouse gas emissions. RF XL would use no chemicals, solvents or external water, and have a smaller surface footprint.

No natural gas would be burned to boil water because steam would be generated from water already present in the reservoir. No external water would be required.

In an article it published on Acceleware’s technology, GE says: “RF XL may reduce capital costs by as much as 70 per cent and operating costs by up to 40 per cent when compared to SAGD.”

Capital costs would be much lower for several reasons.

Since RF XL would just use water that’s naturally present in the reservoir to make steam in situ, no steam plant would be needed. And eliminating the steam plant would eliminate the need for the costly infrastructure that purifies water fed into steam generators.

On the water treatment side, surface facilities would be more like conventional heavy oil operations in that only minimal treatment and separation would be required.

“That's variable from one reservoir to another,” Clark cautions. “But it's not a water treatment plant — there's no re-circulation.”

Also, water-handling costs would be much lower because when no steam is injected, much less water would be produced with the oil. So water-treatment infrastructure would be smaller as well as simpler.

Operating costs, on the other hand, would partly depend on the amount of electricity needed to generate enough RF energy to produce a bbl of bitumen.

Downhole capital costs would be significantly less because of the simplicity of the completion and the smaller-diameter wells.

As explained above, RF XL would use two parallel horizontal wells — an upper heater well with the RF antenna, and a lower oil production well.

But because RF XL puts no water into the reservoir and takes very little out, a production well would produce a third to a quarter of the fluid volume of a SAGD producer because it’s not injecting steam, Clark says, and so the diameter could be much less. Pumps could be much smaller.

Similarly, the diameter of the antenna well could also be much smaller than a SAGD steam-injection well because an RF heater well doesn’t inject steam.

However, Clark says the biggest cost saving would come from the fact that it's a very simple well. There are no flow-control devices, for example.

What exactly is Acceleware?

Acceleware was formed after some electrical engineering professors and graduate students at the University of Calgary developed a way to use graphics processing chips to accelerate the computation of electromagnetic field simulation.

That resulted in a product they could sell to companies designing antennas for cell phones and other devices.

At the time that was quite an innovation. Until then, the graphics processing unit (GPU) on a computer just did graphics; calculations were left to the central processing unit (CPU). There was no good way to program the GPU to do calculations; it was meant to just display pixels.

But the GPU had many more cores than a CPU, so it could do many calculations simultaneously.

For some applications, harnessing the power of the graphics chip changed computation times “from overnight to over coffee,” recalls Michal Okoniewski, a U of C electrical engineering professor and Acceleware’s chief scientist and co-founder.

So how big was Acceleware’s innovation? Enough to prompt NVIDIA Corporation, the Silicon Valley giant whose name is synonymous with graphics controllers, to take a stake in the company in 2007.

Acceleware continued to focus on using GPUs to accelerate non-graphics applications. It realized the same core algorithm, or a very similar algorithm, used in electromagnetic simulation could also be used to simulate what the subsurface looks like, based on the seismic data. Clark says most of its customers for the seismic application are working in difficult offshore geology.

Up to that point the company had no involvement in thermal heavy oil or oilsands.

A phone call from Chevron

In 2010, the company got a phone call from Chevron Corporation, Clark recalls.

The supermajor, which has extensive heavy oil operations in California, was interested in using radio-frequency energy to heat reservoirs, and wanted to know if that was something Acceleware could analyze with its simulation software.

“We said, ‘Well, we would have to adapt some things and hook it up to a reservoir simulator, but it seems easy enough,” Clark recalls. “And we did that.”

At the same time a Calgary-based oilsands producer contacted Acceleware with a similar query. (Acceleware won’t identify the local company, citing confidentiality. Chevron’s involvement is now being disclosed as Acceleware and Chevron will co-present a paper during the March 13-14 SPE Canada Heavy Oil Technical Conference in Calgary.)

“And that's essentially how we got into it,” says Clark. “It all started back in 2010 with a phone call from a couple of oil companies.”

Acceleware developed some technology along with Chevron, and then also developed its own technology.

Like many operators, Chevron trimmed discretionary spending following the oil price slide that began in mid-2014.

“Chevron is kind of backing away a little bit from heavy oil investment and focusing on more shale plays,” Clark says. “They are still very interested in the technology. We talk to them at least once a quarter to update them on what we’re doing and they want to get back at it. It’s just a matter of priorities for them.”

Meanwhile, Acceleware has continued to develop the technology on its own. The company has applied for several patents, including for its “apparatus and methods” for RF heating and for an RF antenna.

Small field test done

About a year ago Acceleware did a field test in a shallow ditch with sand that simulated an oilsands environment.

“And the test was successful,” Clark says. “What we wanted to do was to demonstrate that we could heat the formation as predicted in our simulations.”

He adds: “One of the areas of concern generally with RF heating is how to safely get a high-power RF signal from the surface to ... the reservoir. ... And we were successful in that.”

That field trial was a one-twentieth-scale test — one-twentieth the length and one-twentieth the power of the planned commercial-scale pilot in an actual oilsands reservoir, which is the next step.

Oilsands pilot next

The commercial-scale pilot will involve placing a 1,000-metre antenna in an oilsands formation and heating it with two megawatts of power.

With $10 million in federal and provincial funding in hand, Acceleware is in the process of choosing an oilsands partner and reservoir for the test.

“We have three companies that are very interested in it,” Clark says. “And we just have to choose which one we like the best. And we have a variety of criteria which we’re using to select it.”

However, he acknowledges a consortium isn’t out of the question if oilsands producers decide to share the cost. “But so far, we're talking to three individual companies that would like to do the test individually.”

So the pilot’s exact startup date will be determined by Acceleware’s much larger future partners, but the tech firm hopes to start heating the reservoir by early 2019.

The plan is to run the pilot for at least six months. The full length of the planned project is around 2 1/2 years, but that includes design work, generator development and construction, among other activities.

Key questions

Among the questions the pilot will presumably answer is: How much electricity will be needed to produce a bbl of bitumen? Like the steam/oil ration in SAGD, the power/oil ratio will be a key economic indicator for RF heating.

As GE says: “It takes an enormous amount of RF energy to generate enough heat to operate an in-situ production process in the oilsands.”

Another question is whether RF energy alone — without steam or solvent — can mobilize bitumen fast enough to achieve economic production rates.

Acceleware says its simulations point to economic success, but the proof will be in the pilot results.

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