Simply put, tar sands are the bottom of the barrel. Resorting to these sands is like chewing on your two-year old's beef jerky stick after he's done with it - not very satisfying or tasty. But, hey, you're hungry.
Also called oil sands, they consist of clay, sand, water and bitumen.
Bitumen is the black tarry goo holding it all together and isn't really oil but more akin to asphalt.
Bitumen is a form of oil in a semisolid, degraded form that doesn't flow at normal temperatures and pressures.
At room temperature, its viscosity is most akin to cold molasses, thus making it difficult and expensive to extract.
To further complicate the problem, oil sands are not extracted through the conventional process of a drilling rig but through either strip mining or in-situ techniques.
Normal drilling procedures involve drilling into an oil reserve and allowing the petroleum to naturally flow into the underground cavern and to be lifted, or pumped, out of the ground.
Not so with oil sands.
Strip mining begins with first removing all trees and topsoil.
Then, huge dump shovels scoop up the sands and load them into monstrous dump trucks. The sands are then trucked to the extraction facility.
Once at the facility, the tar sands are mixed with steam and solvents and spun in giant vats to make the bitumen rise to the top.
The leftovers, or waste, (sand, clay, water and/or solvents) is then dumped into ponds and valleys for disposal.
Two tons of oil sands will render about 1/8 of a ton of oil.
Once rendered, this semi-solid mass of bitumen is difficult to transport. Because it does not flow through pipelines like regular oil, it either has to be chemically split or mixed with a lighter petroleum before it can be transported to the refinery where it can be processed into synthetic crude oil.
In-situ (Latin meaning "in place") methods vary. In-situ methods are faster and cheaper than strip mining operations but still are not without problems.
Various in-situ methods are:1. SAGD - steam-assisted gravity drainage using horizontal wells
2. CSS - cyclic steam stimulation using a vertical well
3. VAPEX - vapor recovery extraction using solvents rather than heat
4. THAI - toe-to-heel air injection that uses hot air to begin combustion of the oil sands underground. The combustion melts the bitumen.
The worldwide deposits of oil sands is estimated to be 2.5 trillion barrels, making oil sand possibly the earth's largest resource of hydrocarbons.
Alberta, Canada, has the world's most productive tar sands resource. Current estimates are that 35 billion barrels of oil can be processed from its sand via strip mining. That's enough oil to fuel the entire world for about one year.
Additionally, another 140 billion barrels could be produced in-situ.
However, producing oil from the sand requires a tremendous amount of energy, effort and water. Aside from the fact that the world is short on fresh water anyway, about 25% of the energy contained in the oil is burned up in the production process.
Once all the variables are accounted for, the total net gain for oil sands is only between 5% and 10%.
Due to the enormous amount of labor and energy required for production, each barrel of oil produced from oil sands costs an extra $18 to $23.
Because natural gas is used to heat the steam that drives the bitumen out of the sands, 1,000 c.f. of natural gas is used to produce one barrel of oil from oil sands.
Nearly all estimates for oil sands operations over the next 10 years exceed the projections for available amounts of natural gas! Not to mention the problems associated with fracking and natural gas drilling.
The only other solution is to build more nuclear power plants to generate the heat needed to create the steam.
But, even if that were to happen, is there enough water? Energy economics discusses the benefits versus the costs of of oil exploration.
Environmental Costs of Tar SandsThe production of oil sands produces three times the amount of greenhouse gases as compared to conventional oil production.
Cancer rates of people in close proximity to oil sands appears to be higher than normal.
Arsenic levels in wildlife in close proximity to tar sands have been found to be as high as 453 times the normal level, making the wildlife unacceptable for human consumption.
Perhaps the most significant consequence of oil sands production is the impact it can have on drinking water.
On average, the ratio of water used to oil produced is two to four times more water than oil.
Even worse is the fact that, once the water is used, it's contaminated and cannot be released back into the environment.
Some of the water is reused, but most is pumped into settlement ponds to be retained as toxic waste.
It could take up to 200 years for the smallest particles to settle down to the bottom of this witch's brew that also contains high levels of heavy metals and other life-threatening toxins.
Not only is this loss of fresh water significant to humans, but also to wildlife as well. Additionally, these toxic waste ponds threaten groundwater for years to come.
Not surprisingly, tar sands have been called the oil junky's last fix. And that statement makes sense given the fact that for every barrel of oil produced, enough natural gas is used to heat one family's home for four days.
But hey! This is a crazy world full of people doing crazy things, right? Can you blame the heroin addict for shooting up between his toes once his other veins have collapsed?
Bakken Shale: The Bakken Shale was at one time considered to be a marginal find because the oil was trapped in such low permeable shale.
Deepwater Horizon: Transocean's Deepwater Horizon burned for two days and then sank - an equipment loss of over $200 million.
Directional Drilling: Directional drilling is common practice in shale gas plays such as the Bakken and Barnett Shale, and the selection of drilling tools is critical.
Drilling Mud: Drilling mud can be oil, air, or water based. It cools and cleans the bit, stabilizes the well bore, and creates wallcake.
Exxon Valdez: The effects of the Exxon Valdez oil spill are still being felt almost 30 years later.
Natural Gas Drilling: Natural gas drilling looks to continue because the natural gas reserves of the United States are large enough to fuel our needs for many years to come.
Oil Well Drilling: Oil well drilling requires many pre-drilling decisions, such as whether to reverse circulate and which type of drilling mud to use.
Shale Oil: Shell Oil Company's in-situ conversion process requires a "freeze wall" around the outside perimeter of the shale oil extraction zone to prevent groundwater contamination.
Spindletop: The oil revolution began when Spindletop gushed black gold 150 feet in the air for nine days in 1901, and Howard Hughes invented the roller cone bit.
Tar Sands: Tar sands are a black, tar-like combination of clay, sand, water, and bitumen. They are sometimes called "oil sands" to make them seem more appealing.
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