For the last few years, I’ve led a blissfully car-free (though not carefree) life. I’ve been vaguely aware that the price of gasoline has gone up quite a bit, but not having to buy it myself, I haven’t felt much of a personal impact. I am, however, keenly aware of the many lives lost in the name of oil, not to mention the environmental problems to which it contributes—air and water pollution, global warming, and so on. And oil is destined to become more expensive still as the planet’s finite reserves are depleted. Call me naïve, but it seems to me that any reasonable person would have to conclude we should all do whatever we can to reduce our need for, and use of, the stuff. So when I learn about yet another potential source of oil that could keep our cars running a few more decades, I must confess my first thought is not, “Great! Less dependence on foreign oil!” Instead, I’m thinking, “Drat! Another blow to solar and wind power, another step backward environmentally.”
That rather large disclaimer aside, I do find one particular source of oil increasingly interesting, not least because obtaining the oil requires some impressive feats of engineering. I’m referring to the vast amount of tar-impregnated sand in the Canadian province of Alberta, which some experts are hailing as the world’s largest and most important oil reserve.
A Sticky Situation
The first of many problems with this stuff is what to call it. In Canada, the term oil sands is most often used to describe the deposits, while in the U.S. they are more commonly known as tar sands—a bit of a misnomer since technically, tar is an artificially manufactured product. In any case, it’s a thick, sticky, and smelly mixture of clay, sand, water, and bitumen—a naturally occurring mixture of liquid hydrocarbons, or crude oil. Once separated from the sand and minerals, the crude oil is sometimes referred to as heavy oil, though that term is often used interchangeably with “oil sands” or “tar sands” as well.
Where did the oil sands come from? The sand itself was undoubtedly deposited by ancient rivers. As for the oil, the prevailing theory is that it began as a lighter oil that formed deep underground some distance away and was pushed by geologic pressure to its current location. After being absorbed into the sand, it gradually thickened due to bacterial action.
The sheer quantity of oil sands in Alberta is staggering: the equivalent of an estimated 1.6 trillion barrels of oil, of which at least 300 billion barrels are recoverable—considerably more than in, say, Saudi Arabia. But getting the oil from the ground to your car is a mammoth undertaking. Because the oil sands contain less than 20% bitumen, it takes about two tons of oil sand to yield one barrel of oil. And this oil doesn’t squirt out of the ground for your convenience.
Oil and Water
Most of the oil sands are not on or near the surface of the ground; workers must sometimes dig 200 feet (61m) or more to reach the deposits. Because the oil sand is both heavy and sticky, even more effort is required to bring it to the surface. Furthermore, extracting the oil from the sandy mixture is no mean feat. Because the tarry substance is much too viscous to flow through pipes, it has to be shoveled out and carted away in gigantic dump trucks. Before it can be used, the bitumen must be separated from the sand. There are several techniques to achieve this, but all of them involve large quantities of water and elaborate equipment. To oversimplify somewhat, oil companies blend the oil sand with water, and sometimes solvents, until the mixture becomes thin enough that the sand and the bitumen can separate (sometimes with the help of a centrifuge). The reliance on water makes the process all the more challenging in winter, when temperatures of –40° (C/F) in Alberta are not uncommon. Once the sand and water are removed, the bitumen must be processed further under high heat to remove impurities and break it down into a more useful and smoother-flowing oil. Even then, it must go through multiple refinement stages to become fuel.
Given all the time, effort, and equipment needed to recover usable oil from oil sands, the cost of production is quite high—about three times that of drilling for oil. However, this is a tremendous improvement over the situation a few decades ago, when production costs far outweighed the value of the oil recovered. Improvements in technology are slowly but steadily making the process even more cost-effective. One technique, for example, involves forcing steam into a deep well to melt the bitumen so that it will flow to the surface—without the sand. Besides reducing transportation and refining expenses, steam extraction also provides access to bitumen that’s too deep for conventional mining.
As challenging as it is to extract oil from oil sands, Alberta is already producing upwards of 600,000 barrels a day, a figure that’s likely to triple within a decade. Oil sand deposits in several other parts of the world—notably Venezuela—are being exploited with equal success. And yet, even as output increases and costs decrease, other problems loom large. Most conspicuously, the mining operations are often devastating to the landscape and vegetation. The separation and refining process requires a great deal of heat, which usually comes from natural gas—consuming one natural resource to get access to another. And the equipment used to extract and process the oil sands also creates a significant amount of air pollution.
Still, if I were the type of person who invested in new methods of energy production, I’d bet heavily on oil sands to make a fortune in a few years. Then just think how much solar energy research I could fund! —Joe Kissell