What are some major disadvantages of the Oil and Tar Sands?

Answer 1

It is somewhat more energy intensive to recover oil from oil sands than it is from conventional oil wells. The "oil" in oil sands is closer to tar and will not flow unless heated or diluted with lighter hydrocarbons. Recovery is usually by either strip mining (where the oil sand is closer to the surface) or by injecting steam, solvents, and/or hot air into the sand (where the sands are deeper). Once the tar/oil is recovered, it must be further pre-processed to turn it into a form that can be handled by conventional oil refineries. This usually requires 3 steps:

1. removal of water, sand, physical waste, and lighter products,
2. catalytic purification to remove sulfur, metals, and nitrogen,
3. hydrogenation - usually through hydro-cracking.

These pre-processing steps take large amounts of energy and water, while emitting more carbon dioxide than conventional oil. Most of the oil sands that are currently used as sources of oil use processes that require quite a bit of water for the recovery process. For this reason 'sine' oil sand deposits are even more difficult to process. For example the large oil sand deposits in eastern Utah, which is quite arid, are not being mined.

There are also political considerations:

President Clinton, by executive order, placed most of the oil sand deposits in eastern Utah off limits for development (some have speculated that it was in retaliation for finishing 3rd in Utah in the Presidential election of 1992 behind Bush and Perot - Bush 43.36, Perot 27.34%, Clinton 24.65%). At the very least, order was driven by eco-politics rather than any issues with technology or economics.

One of the largest oil sand deposits in the world is located in Venezuela which nationalized its oil industry in 1975-1976 placing it under the country's state-run oil and natural gas company but allowed for some private development. In 2001, Venezuelan president Hugo Chávez imposed a new Hydrocarbons Law that raised royalties paid by private companies from 1-17% to 20-30%. In 2007, Chávez announced the nationalization of the oil industry and required that all private companies hand over majority ownership to the government of Venezuela. Any company that refused to sign over the majority ownership simply had all their assets seized and turned over to the state-run oil company. This put a damper on oil sand development since the companies with expertise to develop it were no longer willing to risk losing their investment to another seizure by the Chávez government.

Answer 2

I generally answer questions on fossil fuels. I assume that your question refers to tar sands as fossil fuels. If not, please re-submit your question. Tar sands production is frustrating. Suppose you had a billion dollars in the bank, but to get the money out, you had to walk 5 miles to the bank, and then could only get $10 out each day. Tar sands are very heavy oil in sand formation. It frequently requires energy (steam) to produce these fields. As the price of oil goes up, so does the cost to produce these fields. However, higher oil prices have renewed interest in tar sands production. See related link.