Beyond conventional crude oil: Shale rock and tar sand

In just over 200 years, we have consumed an incredible amount of oil, leaving it all but gone and our planet’s climate seriously impacted

Crude oil is an integral part of our life. Today, extracting, refining and retailing oil is the single largest industry in the world. Yet, we probably give little if any thought about what will happen when the last drop of oil is extracted from the well?
A so-called fossil fuel, “conventional” crude oil is a remnant of organic matter – mostly dead animals. It takes fossil fuels hundreds of millions of years to form, but we are using them, particularly oil, at a rate faster than Mother Nature can replenish them. In fact in just over 200 years, we’ve consumed an incredible amount of oil, leaving it all but gone and our planet’s climate seriously impacted.
According to the US Energy Information Administration, global consumption of petroleum and other liquid fuels grew by 1.3 percent in 2015 and is expected to grow by the same amount in 2016 and 2017. At this rate, the total technically recoverable reserves will dry up by the year 2060. Not everyone will agree on the estimate of lifespan, but the reality of the situation is because of its limited availability, conventional oil wells are bound to run dry everywhere sooner than later.
However, if we want to continue our romance with the “black gold” even after the last drop of conventional oil has been extracted, there are two “unconventional” sources at our disposal – shale rocks and tar sands. There may be plenty of oil hidden in these sources, but there are plenty of problems also that accompany their exploitation.
Shale is a sedimentary rock containing an organic material called kerogen, which can be separated from the rock by heating. In liquid state, this thick, oily substance is called shale oil. Like crude oil, it can be refined and purified to make gasoline and other by-products.  
There are two ways to extract oil from the shale. The first, an “ex-situ” process known as surface retorting involves mining the shale in an open-pit or underground mine, crushing it and then distilling it at temperatures close to 1000 degrees Fahrenheit. The other method is an “in-situ” process whereby shale deposits are first fractured by explosives. A fire is then started underground in the oily rock and forced through the deposit. The heat from the fire drives off some of the oil, which is collected and pumped to the surface.
The chief advantage of shale oil is its large supply.  United States and Canada are literally floating on shale oil. The total oil content in shale rocks in Western Colorado, Eastern Utah and Wyoming is estimated to be 2.6 trillion barrels, which is many times more than the oil reserves in Saudi Arabia. Large deposits are also found in the Commonwealth of Independent States and China.
The main disadvantage of shale oil is cost. Shale oil technology is expensive. It is energy intensive too. The average "energy returned on investment," or EROI, for shale oil is roughly 3:1. In other words, 3 units of shale oil are obtained for every one unit of other energy used to extract it. In contrast, the EROI of conventional oil is 25:1.
Shale oil creates serious environmental impacts as well. At a time when nations of the world are making concerted, forward-thinking efforts to reduce greenhouse gas (GHG) emissions, commercial mining and extraction of shale oil would produce 15 to 50 percent more GHG emissions compared to conventional oil production.
Besides contributing to global warming, shale oil would adversely affect the air, water and land around the mining areas. Surface retorting produces enormous amounts of solid waste, called spent shale. A small operation producing 50,000 barrels per day would generate 15-20 million tonnes of spent shale per year. Since shale expands by about 12 percent on heating, not all of the spent shale could be disposed of in the mines from which the rocks came. Dumped elsewhere, the spent shale may be leached by water, producing an assortment of toxic organic pollutants that could contaminate underground and surface water. Moreover, during the distillation process, many toxic pollutants including sulfur dioxide, lead and nitrogen oxides will be released into the air.
Although shale deposits and the basic techniques for shale oil recovery have been known for more than half a century, no significant commercial production has developed. Water issues have long been viewed as a major constraint on large-scale development of shale oil. Surface mining and retorting of shale would require approximately 5 barrels of water for each barrel of oil produced. But shale rocks are typically found in arid areas where water is a scarce commodity.
Tar sands are sand deposits impregnated with a petroleum-like substance known as bitumen. Much of the world's oil (more than 2 trillion barrels) is in the form of tar sands, although it is not all recoverable. They are found throughout the world with huge deposits in Alberta (Canada), Commonwealth of Independent States and Venezuela.
Tar sands can be strip-mined and treated in a variety of ways to extract the bitumen. Hot-water processing is the method preferred by oil companies for extracting oil commercially. In situ methods similar to those used in shale oil extraction are also used.
Tar sands are plagued with many of the problems that face shale oil. They expand by 30 percent after processing and as with shale oil, its production requires large amounts of water – several barrels for each barrel of oil produced – which is badly polluted in the process. Additionally, compared to conventional oil, extraction and production of oil from tar sands emit three times more carbon dioxide.
The most significant barrier to tar sands development is poor economics. They are expensive to mine and have poor energy efficiency. Tar sands retrieved by surface mining has an EROI of only about 5:1 while those retrieved from deeper beneath the earth fares even worse, with a ratio of just 3 to 1.
So, what’s the bottom line? When the entire reserve of fossil fuels, including shale oil and tar sands, will be depleted, the amount of GHGs that will be released into the atmosphere will be enough to transform the Earth into today's Venus – a planet that has possibly surpassed even Dante's vision of hell. The Earth will still keep on spinning, but as the fourth dead ball of rock.
It is, therefore, in our best interest to move away from fossil fuels and make renewable and alternative sources of energy niche players in the global energy mix without any further delay.
Indeed, a green energy revolution is taking place all over the world, underscored by the steady expansion of renewable and alternative energy sectors.

The writer is Professor of Physics at Fordham University in New York

Beyond conventional crude oil: Shale rock and tar sand

In just over 200 years, we have consumed an incredible amount of oil, leaving it all but gone and our planets climate seriously impacted

Crude oil is an integral part of our life. Today, extracting, refining and retailing oil is the single largest industry in the world. Yet, we probably give little if any thought about what will happen when the last drop of oil is extracted from the well? A so-called fossil fuel, conventional crude oil is a remnant of organic matter mostly dead animals. It takes fossil fuels hundreds of millions of years to form, but we are using them, particularly oil, at a rate faster than Mother Nature can replenish them. In fact in just over 200 years, weve consumed an incredible amount of oil, leaving it all but gone and our planets climate seriously impacted. According to the US Energy Information Administration, global consumption of petroleum and other liquid fuels grew by 1.3 percent in 2015 and is expected to grow by the same amount in 2016 and 2017. At this rate, the total technically recoverable reserves will dry up by the year 2060. Not everyone will agree on the estimate of lifespan, but the reality of the situation is because of its limited availability, conventional oil wells are bound to run dry everywhere sooner than later. However, if we want to continue our romance with the black gold even after the last drop of conventional oil has been extracted, there are two unconventional sources at our disposal shale rocks and tar sands. There may be plenty of oil hidden in these sources, but there are plenty of problems also that accompany their exploitation. Shale is a sedimentary rock containing an organic material called kerogen, which can be separated from the rock by heating. In liquid state, this thick, oily substance is called shale oil. Like crude oil, it can be refined and purified to make gasoline and other by-products. There are two ways to extract oil from the shale. The first, an ex-situ process known as surface retorting involves mining the shale in an open-pit or underground mine, crushing it and then distilling it at temperatures close to 1000 degrees Fahrenheit. The other method is an in-situ process whereby shale deposits are first fractured by explosives. A fire is then started underground in the oily rock and forced through the deposit. The heat from the fire drives off some of the oil, which is collected and pumped to the surface. The chief advantage of shale oil is its large supply. United States and Canada are literally floating on shale oil. The total oil content in shale rocks in Western Colorado, Eastern Utah and Wyoming is estimated to be 2.6 trillion barrels, which is many times more than the oil reserves in Saudi Arabia. Large deposits are also found in the Commonwealth of Independent States and China. The main disadvantage of shale oil is cost. Shale oil technology is expensive. It is energy intensive too. The average energy returned on investment, or EROI, for shale oil is roughly 3:1. In other words, 3 units of shale oil are obtained for every one unit of other energy used to extract it. In contrast, the EROI of conventional oil is 25:1. Shale oil creates serious environmental impacts as well. At a time when nations of the world are making concerted, forward-thinking efforts to reduce greenhouse gas (GHG) emissions, commercial mining and extraction of shale oil would produce 15 to 50 percent more GHG emissions compared to conventional oil production. Besides contributing to global warming, shale oil would adversely affect the air, water and land around the mining areas. Surface retorting produces enormous amounts of solid waste, called spent shale. A small operation producing 50,000 barrels per day would generate 15-20 million tonnes of spent shale per year. Since shale expands by about 12 percent on heating, not all of the spent shale could be disposed of in the mines from which the rocks came. Dumped elsewhere, the spent shale may be leached by water, producing an assortment of toxic organic pollutants that could contaminate underground and surface water. Moreover, during the distillation process, many toxic pollutants including sulfur dioxide, lead and nitrogen oxides will be released into the air. Although shale deposits and the basic techniques for shale oil recovery have been known for more than half a century, no significant commercial production has developed. Water issues have long been viewed as a major constraint on large-scale development of shale oil. Surface mining and retorting of shale would require approximately 5 barrels of water for each barrel of oil produced. But shale rocks are typically found in arid areas where water is a scarce commodity. Tar sands are sand deposits impregnated with a petroleum-like substance known as bitumen. Much of the worlds oil (more than 2 trillion barrels) is in the form of tar sands, although it is not all recoverable. They are found throughout the world with huge deposits in Alberta (Canada), Commonwealth of Independent States and Venezuela. Tar sands can be strip-mined and treated in a variety of ways to extract the bitumen. Hot-water processing is the method preferred by oil companies for extracting oil commercially. In situ methods similar to those used in shale oil extraction are also used. Tar sands are plagued with many of the problems that face shale oil. They expand by 30 percent after processing and as with shale oil, its production requires large amounts of water several barrels for each barrel of oil produced which is badly polluted in the process. Additionally, compared to conventional oil, extraction and production of oil from tar sands emit three times more carbon dioxide. The most significant barrier to tar sands development is poor economics. They are expensive to mine and have poor energy efficiency. Tar sands retrieved by surface mining has an EROI of only about 5:1 while those retrieved from deeper beneath the earth fares even worse, with a ratio of just 3 to 1. So, whats the bottom line? When the entire reserve of fossil fuels, including shale oil and tar sands, will be depleted, the amount of GHGs that will be released into the atmosphere will be enough to transform the Earth into todays Venus a planet that has possibly surpassed even Dantes vision of hell. The Earth will still keep on spinning, but as the fourth dead ball of rock. It is, therefore, in our best interest to move away from fossil fuels and make renewable and alternative sources of energy niche players in the global energy mix without any further delay. Indeed, a green energy revolution is taking place all over the world, underscored by the steady expansion of renewable and alternative energy sectors. The writer is Professor of Physics at Fordham University in New York