Infinity, Genetics and Oil

What do you do when you have more choices than atoms in the universe? You develop computer software to make the best decision… and not just any software but the type that is modeled after life itself. Enter Genetic Algorithms (GA), a class of computer programs that mimic the process of biological genetics in order to find the best possible solvent-steam recipe for getting the most oil out of a reservoir.

“For the last 15 years researchers have been trying to get the optimal amount of oil out of various geologic formations, by injecting different combinations of solvents and steam,” explains Laricina Energy Ltd.’s Neil Edmunds, Vice President Enhanced Oil Recovery. “The very first time we used this new software, it ran for two weeks and produced results that were superior to all the best techniques that human beings had written down over the last 15 years.”

The use of solvent and steam is preceded by technologies that injected only steam, a common extraction approach of in-situ oil sands operators today. With hard sticky bitumen deep below the surface in oil sands geologic formations, the steam heats it enough so that it can be extracted like conventional oil. This is often done through a process called steam assisted gravity drainage (SAGD), which is one of the most well known in-situ techniques. Latin for “in place”, in-situ technology recovers bitumen from deep below the earth’s surface using wellbores. In-situ operators use various approaches to loosen the viscosity of the bitumen enough so that it can flow up through a production well. In the case of SAGD technology, steam is injected into one horizontal well and the softened bitumen flows down into a parallel production well where it is pumped to the surface.

SAGD requires energy and water (mostly non-potable groundwater from deep saline aquifers) to generate the steam needed to heat the bitumen. Industry has been improving the efficiency of SAGD with engineering and better technology that continues to reduce oil sands water and energy use which not only improves the economics but reduces greenhouse gas emissions. For companies like Imperial Oil, Laricina and EnCana, one solution is using solvents which act as diluents for bitumen. On one end of the solvent-use spectrum, there is the cold solvents approach, which basically involves no steam and injecting a solvent like propane into the oil to make it thin enough to be pumped. While this approach requires minimal energy and has no emissions or water usage, it is also comparable to the speed at which molasses flows on a cool January morning.

“If the process is too slow, you end up needing to drill too many wells,” explains Edmunds, “which impacts your rate of return and efficiency”. As it is right now, the cold-solvent extraction approach is too slow to be efficient. Of course, on the other end of the spectrum is the previously discussed SAGD approach in which no solvents are used at all. The gamut of possibilities that sits between the two extremes is astronomically large.

“The problem with using solvents is the number of choices you can make,” explains Edmunds.  “If you have a certain amount of steam and two types of solvents, for example, and let’s say we’re going to allow for a different injection rate every few months, and you do that for five years, you end up with more possibilities than the number of atoms in the universe.”

Making Choices

So how exactly does it all work and why are there so many changing variables involved? Basically, a solvent combination with a low boiling point is injected together with the steam, Edmunds explains. As the steam mixture moves out into the reservoir the steam condenses at a higher temperature than the solvent, causing the solvent vapour to move ahead of the steam, essentially “beating the steam to the punch.” Ultimately this allows the entire steam front to move through the reservoir quicker as the solvent mobilizes the oil in regions that are cooler than the steam zone. “At the end of the day we’re draining the same oil using half the steam and therefore half the water and half the carbon emissions.”

Of course the term “half” in all of these contexts is variable depending on the choices an engineer makes on a project. And it’s not just the solvent types, mixes and quantities that make for an expansive array of possibilities, but other variables as well, such as the shape, size and characteristics of a reservoir or the steam and solvent injection rate. Even economic factors such as market prices of solvents can exponentially increase the number of variables in a given operation.

“If there are 60 possible variables, and each one of those variables can have 10 values, the total number of different options is 10⁶⁰,” explains Edmunds, likening the optimization process to finding the highest peak of a mountain, which is usually obscured by clouds. “In this sense, the surface to be optimized on cannot be seen (only sampled at different points), it exists in many, many dimensions, it is very nonlinear and therefore the same action often generates different or opposite effects when applied in different situations.” In other words, it makes advanced calculus look like a game of duck-duck-goose.

But that hasn’t stopped companies from trying to nail down an optimal process. In the end, the sheer enormity of possibilities explored on a pencil-to-paper basis was enough to drive throngs of engineers crazy, making the transition from wetware to software an inevitable part of the technology’s evolution.

Using Smarter Software

“Genetic Algorithms is a program for automating the process of optimizing complex and nonlinear problems,” explains Edmunds, adding that GA is basically an implementation of some of the basic mechanisms of biological evolution. And it seems to make sense. Genetic variation is, after all, a process that also optimizes outcomes that are best suited to organisms’ environments and also deals with a vast selection of seemingly infinite variables.

Sticking with the analogy, the engineer creates a ‘genome’ that defines an arbitrary number of variables to be investigated, each with a finite range and specified number of possible values. Using the software, the genome is a simulation that reflects the particular values encoded in an arbitrary bit string of a certain length. The engineer could input an ‘objective function’ for a given simulation, such as ‘minimize supply cost’, as one example out of many. The program would then calculate the ‘score’ based on economic evaluation.

“Essentially, we’re just borrowing from nature itself to find ways to get the most amount of oil for the least amount of cost and environmental impact,” concludes Edmunds who also teaches as Adjunct Associate Professor in the Department of Chemical and Petroleum Engineering at University of Calgary’s Schulich School of Engineering.

So far, Laricina has conducted a series of tests with solvents in its carbonate Grosmont Formation at Saleski, southwest of Fort McMurray. As GA software continues to simulate and model various solvent-steam combinations, the company expects commercial production to begin in 2014 and grow steadily for 10 to 15 years, all the while improving recovery techniques, lowering operating costs and reducing greenhouse gas emissions.

Laying it on thick

So, you’ve heard about oil sands in a documentary or on the news. You’ve heard, perhaps, in conversation or classroom debates, about its impact on the environment. Perhaps you even know some people who have packed their bags and headed to Alberta to get their own nugget of black gold and share in the wealth. But this Texas, er…Alberta tea doesn’t come up from the ground like a bubbling crude as Jed observed in the famous classic, Beverly Hillbillies.

Instead, it comes in the form of bitumen… gummy, gooey and thicker than molasses in January. To make matters worse, it’s mixed right in with the sand, presenting a grueling challenge for industry. How to separate such an unruly brew from the ground is for another story, but this is a tale about the origins of bitumen’s thick skin and how we toil to tame this intractable taffy of the turf.

Thicker than peanut butter, but not quite as tasty, Athabasca bitumen has a viscosity, or resistance to flow, of more than 500,000 centipoise (cP) at room temperature.

Now, with every story you have some sort of conflict, a rising action, a climax and a conclusion. The conflict here is bitumen’s high viscosity, and the implications it has on this resource’s means of production and impact on the environment.

That’s a heavy story man

A penetrating glimpse inside the molecular structure of bitumen reveals the cause behind its thickness. Are you ready for it? Bitumen is thick because… (insert drum roll)… it is heavy.

You may have heard the term “heavy oil” before, but few people know what this actually means. What makes heavy oil heavy? What makes oil sands heavier than conventional oil or methane?

Essentially, when we say a certain oil is heavy, what we’re really saying is that it is carbon heavy, meaning that type of oil has longer and more complex carbon chains than other types of oil. Light crude oil, such as conventional Alberta crude, contains many small, hydrogen-rich hydrocarbon molecules whereas heavy crude oil contains many large carbon-rich hydrocarbon molecules.

As you can see, the antagonist in this particular story is the carbon molecules.

So, in order to bring bitumen to a viscosity that refiners can actually work with, you have to upgrade the bitumen, which essentially means, getting rid of some of the carbon, resulting in a product that is less thick. In fact, when you consider the extra process bitumen has to go through in order to get rid of all that heavy carbon, you can see where the environmental conflict lies. Additional energy is required to separate bitumen from the sands and upgrade it. As well, heavy crude oil requires more refining to transform it into transportation fuels. And of course, more energy equals more greenhouse gas emissions if the energy being used to power the extraction, upgrading and refining processes is natural gas.

So the rising action in this story has everything to do with the rising demand for cheap energy around the world, the important role of oil sands in meeting that demand and the unrelenting challenge of reducing greenhouse gases. The plot starts to thicken as the bitumen thins because at each stage of carbon removal, the viscosity of the bitumen becomes less and less, making it easier to work with. But the overall energy used becomes more and more. It’s really annoying.

Technology is starting to change all that. Scientists are exploring ways to reduce the energy used in oil sands extraction and upgrading. One approach in the pipes is adding bacteria to bitumen deep underground, converting it into methane, which is easier and less energy intensive to extract. Another in-situ approach of extraction is Toe to Heel Air Injection (THAI) which involves injecting air into the ground, causing combustion. As the bitumen heats it becomes less viscous allowing it to flow towards the well. As it flows it leaves some of the heavy carbon behind in a process called “coking”. Coking usually happens above ground as part of the upgrading process but doing it underground results in a lighter product that can be transported through pipelines, is partially upgraded and results in fewer lifecycle greenhouse gas emissions.

Of course, another approach is to use renewable energy to power any or all of these processes. The challenge here is that renewable energy is not as cheap and bountiful. But as society and governments evolve towards increased sustainability, that could soon change.

Although renewables are rapidly being embraced across the globe, it is important to recognize the degree to which we depend on oil, even as we make the transition to greener alternatives. Sure we can heat our homes with solar and earth energy, and derive electricity from nuclear, wind and hydro, but there remains a conundrum surrounding our cars. Solar, nuclear, wind and hydro-powered cars are still a long way off. Sure we have hybrids, but for the most part they still run on gasoline and electric cars have very limited ranges and low speeds. As well, a lot of electricity used to power them is coal or natural gas fired thermal electricity.

Now, every good story must have at least a few literary devices, and the most delicious of them is irony. We labour to make bitumen and the resulting crude products less viscous right from the extraction phase (especially with in-situ extracting techniques) through to the upgrading and then refining phase. The most premium petroleum products are the highly refined and less viscous transportation fuels such as jet fuel and gasoline. Ironically, lubricating oil, which is a highly refined product, needs to be more viscous so as not to ruin the engine. So after all this work to make it less viscous, additives are put in to make sure it retains its viscosity.

Because the oil sands and its continually evolving technologies are a work in progress, this story is too. There are yet so many variables that could affect the outcome, such as the direction of the economy, incentive to invest in research and development and carbon pricing laws. While the U.S. is introducing a tough stance on carbon emissions through its Green Energy and Security Act, Canada is waiting to see what happens before coming up with anything definitive.

But the rest of the world isn’t holding its breath. Already the wheels are in motion to come up with a global carbon pricing scheme in an effort to reduce world greenhouse gas emissions and to ensure an even playing field for renewable energy to compete in the global energy market. It may be safe to predict that the outcome of the upcoming conference of world leaders in Copenhagen this December could serve as a climax for this story.

Most importantly, however, is the conclusion and that rests in the hands of energy consumers as well. Mitigating climate change is a heavy topic and while many remain thick headed towards a potentially warming planet, many more are working towards a positive conclusion for the planet – one where energy, the economy, the environment and its inhabitants live happily ever after.

The Great Oil Sands Journey Part 2

Do I have to separate you three?

So now that you know the origins of the sands, what then of the process that brings the oil from the sand to your car?  Two important areas of discussion around this include the separation process, which we discuss this week, and next week it’s the upgrading/refining process, which is part three of this five part series.

Wells to Wheels
Part two of a five-part series

First, in order to appreciate the great deal of work that goes into this process, let’s look at the relationship between the bitumen, the water and the sand on a smaller scale. As you can see, water, bitumen and sand are pretty tight.

As you could probably imagine, having sand and water mixed with the bitumen just won’t do. Not for our purposes anyways. About 200 years ago explorers reported the naturally occurring bitumen seeping up on the banks of Athabasca River and, for many years to come, scientists would rack their brains over how to separate the precious bitumen from the sand and water. In fact, even 60 years ago observers doubted the feasibility of producing oil sands economically. Like celebrity marriages these components were costly to separate, but time has proved that it can be done at increasing rates of speed and efficiency.

So this is as much a story about creativity, perseverance and innovation as it is about the origins and makeup of the oil sands. It is the process and evolution of oil sands technology and innovation that has ultimately transformed the oil sands into a profitable resource today. And the evolution is still in progress.

Around 1915, Sidney Ells, an engineer with the federal Department of Mines, was the first to suggest using hot water to separate the three. In 1925, a man with the Alberta Research Council named Karl Clark successfully demonstrated a separation method using hot water and caustic soda, a technique employed by two mining operations today. Most mining operations today, however, do not require caustic soda.

Mining is the approach of choice when bitumen deposits lie close enough to the surface to be removed using trucks and shovels.

Here’s mining in a nutshell

Mining, one of two techniques employed in oil sands extraction, receives the most attention from environmentalists, journalists and concerned energy consumers because it disrupts the land and results in tailings ponds. A mixture of water, clay, sand, residual bitumen  and other hydrocarbons, salts and trace metals produced through the extraction process, tailings are often stored in discontinued mine pits where the mixture is left to settle. Problem is, due to all the fine particles, it takes a while to settle on its own.

Mining technology and research today are focused around ways to hasten the settling process, to reduce or eliminate tailings ponds altogether or speed up the process of reclaiming the land back to its original state and, finally, to reduce the amount of energy used in the extraction process. Examples of today’s oil sands mining innovations include:

• Syncrude’s low energy extraction process (Aurora Mine)
• Canadian Natural’s CO2 injection process (Horizon Mine)
• Canadian Natural, Syncrude, Imperial Oil and Suncor’s dry stackable tailings (also called consolidated tailings)
• Gradek Energy Inc.’s polymer beads (used by Syncrude)

Despite all these neat advancements in mining technology, only 20 per cent of all oil sands reserves contain bitumen close enough to the surface to be mined. The remaining 80 per cent lies too deep below the earth’s surface.

In-situ techniques are used for extracting oil from oil sands reservoirs deep beneath the surface using heat or solvents or other processes to soften the bitumen enough so it can flow up through the well.

Here’s in-situ in a nutshell

Most major in-situ projects inject steam through a well, heating the bitumen enough so it can be pumped to the surface. While this is often accomplished by injecting steam, there are also other approaches, including injecting solvents, natural gas liquids, or oxygen, which causes an underground combustion. In-situ bitumen production requires further processing to remove water and sand particles and recycles 90 per cent of the water used. Remaining solids are put in landfills, injected underground or used to pave roads. After processing, the bitumen is diluted with pentanes and heavier hydrocarbons obtained from natural gas processing. The resulting mixture is then shipped by pipeline to an upgrader or refinery.

The most popular in-situ method is called Steam-assisted Gravity Drainage, or SAGD, which involves two horizontal wells, one of which (the upper one) is used to inject the steam. The steam heats the bitumen enough so it can flow into the production well (the lower one) and is then pumped to the surface. Cyclic Steam Stimulation (CSS) is a similar method that uses only one well instead of two.Now, the astute observer might be keen to ask how in-situ fans respond to environmentalists concerned about the use of water and energy needed to make the steam.

One has to dig deeply for the answer to this one… deep underground that is. That’s because in-situ operators use heat and undrinkable water from subsurface aquifers to generate the steam, which means use of water from the Athabasca River or other local water supply is negligible. As well, some in-situ operators are turning to alternative energy sources to power their operations, such as geothermal energy, which also resides deep underground. So whether you’re talking about energy, water use or the overall technique, conversations about in-situ can get pretty deep.

Ultimately, in-situ technology advancements today focus on using cleaner energy and less of it as well as minimizing or eliminating water use. Examples of this include:

• Firefloods, such as Petrobank’s Toe to Heel Air Injection (THAI) which uses underground combustion rather than steam to generate heat. This technique also reduces GHGs as it partially upgrades the heavy oil into a lighter oil while it is still underground. It does this through coking, which is explained further down.
• Vapour extraction, or VAPEX, which is similar to SAGD described above but instead of steam, natural gas liquids such as ethane, propane or butane are injected, acting as a solvent to loosen the bitumen.
• Cold production which produces sand along with the oil, improving oil recovery rates.

So next time you encounter a pair of people who get along like peas and carrots, and they happen to be engineers or in the oil industry, just say, “Those two are so close, they’re just like bitumen and sand.” Then pause for effect and say, “except not even mining or in-situ technology could separate them.”

Next week:  The second part of Wells to Wheels – Bitumen finally grows up