Shale Oil Extraction, A Water Pollution Method

Bakken shale oil well - photo credit: National Geographic

Bakken shale oil well – photo credit Eugene Richards National Geographic

We well know that potable water, once polluted, cannot be replaced easily. One of the methods of using potable water is extraction of oil from shale.

Getting crude oil from rock represents perhaps the most difficult process of extraction. Oil shale must be mined using either underground- or surface-mining methods. After excavation, the oil shale must undergo retorting. This is when the mined rock is exposed to the process of pyrolysis — applying extreme heat without the presence of oxygen to a substance, and producing a chemical change. Between 650 and 700 degrees Fahrenheit, the kerogen — the fossil fuel trapped within — begins to liquefy and separate from the rock.

The oil-like substance that emerges can be further refined into a synthetic crude oil. When oil shale is mined and retorted above ground, the process is called surface retorting. The problem is that this process adds two extra steps to the conventional extraction process in which liquid oil is simply pumped from the ground. In addition to mining, there’s also retorting and refining of the kerogen into synthetic crude. Oil shale presents environmental challenges as well. It takes two barrels of water to produce one barrel of oil shale liquid.

And without cutting-edge water treatment technology, the water discharge from oil shale refining will increase salinity in surrounding water, poisoning the local area.

There’s also the matter of the rocks. Every barrel of oil produced from shale leaves behind about 1.2 to 1.5 tons of rock.

What should be done with this remaining rock? There are certainly projects that require loose rock — like covering ground beneath highway overpasses to discourage homeless settlements. But the demand may not meet the supply if oil shale production is ever conducted on a massive scale.

The trade off is ”Two barrels of water to make one barrel of oil” and that is not the only thing that is an issue with oil; there is the main problem of transportation of oil, both by rail and by pipeline. Overall, the history of oil and pollution is not a good one to review or research. Yet our dependency on it has led us to this downside that promises no good return.

Fracking is slowly emerging as the worst in the consumption of potable water and pollution of the water used but also the area where fracking is done.

Fracking is controversial because it uses a lot of resources and its effects are unknown. Before the first drop of oil can be extracted, each well typically needs 800 truckloads of water, as well as hundreds of truckloads of other material. Unless the water is already on site, it must be trucked in, and stored in massive tanks, before the fracking can begin. The composition of the fracking fluid is proprietary to each company — and a trade secret. In addition, frackers don’t have to comply with the Safe Drinking Water Act. Therefore, it’s unknown what chemicals could ultimately be leached into the water table decades, or even just years, from now.

Most of the water that’s pumped in returns to the surface. It can be contaminated with unknown underground chemicals, including trace amounts of radioactive material. Normal water treatment facilities are not equipped to deal with this water, so it is pumped into ponds. The long-term impact of this water is still being studied.(Source: University of Michigan, The Impact of Fracking; National Geographic, Bakken Shale Oil, March 2013; EIA, North Dakota Production Reaches New High in 2012, March 18, 2013)

Water is a scarce commodity that must be conserved and managed. Due to population growth and environmental causes, this once-abundant natural resource is in increasingly short supply. Utility companies are raising water rates as they grapple with escalating treatment costs, replacement of aging infrastructure, accelerating power prices, regulatory mandates, and water scarcity. Water covers roughly 71% of the surface of this blue planet, but most of that is seawater. About 3% of the earth’s water supply is fresh water, and nearly 70% of that is confined in glaciers and polar ice caps. Only 1% of the water on this planet is suitable for drinking, and only 0.08% of the world’s drinkable water is accessible to humans.

The old saying ‘oil and water don’t mix’ is an understatement when it’s pegged to shale oil and water pollution.

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Categories: Conservation, Earth Science, Economics, Environment, Fossil fuels, Geology, Hydrology, Natural resources, Pollution, Science, Water quality

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