From a VERY conservative site
What’s an Oil Subsidy?
Oil Subsidies That Should Be Removed
First, let’s take a look at oil subsidies that are obvious and unnecessary. Congress should eliminate the following subsidies:
* Government R&D. The Department of Energy (DOE) has spent taxpayer dollars on oil research and development, including funding for unconventional oil, gas, and coal. Although President Obama’s FY 2012 budget request significantly cuts funding for the Office of Fossil Energy, decreasing its size by $417.8 million below the FY 2010 appropriation, it does not go far enough. The only funding in this area should maintain the Strategic Petroleum Reserve, for which the President’s budget requests an appropriate $121.7 million. Eliminating all other fossil energy funding would save $399 million.
* Enhanced Oil Recovery (EOR) Tax Credit. Oil producers receive a 15 percent tax credit for costlier methods and technologies, such as injecting liquids and carbon dioxide into the earth. Many EOR processes are no longer in use, and the tax credit applies only when the price of oil falls below a certain level.
* Marginal Well Production Credit. Marginal wells produce 15 or fewer barrels of oil per day, produce heavy oil, or produce mostly water and fewer than 25 barrels of oil per day. The marginal well production credit is another safety-net tax provision. This is another preferential tax credit that Congress should repeal.
http://www.heritage.org/Research/Reports/2011/05/Whats-an-Oil-Subsidy
From wikipedia
Public subsidy
The United States government provides a large subsidy to oil companies, with major tax breaks at virtually every stage of oil exploration and extraction. Capital expenses, including the costs of oil field leases and drilling equipment, are taxed at an effective rate of nine percent, which is a much lower rate than the 25% rate for general business taxes and lower than the taxes of virtually any other industry, according to a 2005 study by the non-partisan Congressional Budget Office. For example, while the Deepwater Horizon oil rig was registered in the Marshall Islands, since registering off-shore lowered the U.S. tax liability, the U.S. government was giving the rig's owner, British Petroleum (BP), a major tax break when BP leased the rig: 70% of the rent was written off in the form of a tax break used only by the oil industry, for a tax deduction of more than $225,000 per day from the day the lease began.[2
http://en.wikipedia.org/wiki/Petroleum_industry#Public_subsidy
====
Bonus question:
Since some of you will insist that they are subsidized, although you likely won't be able to demonstrate exactly how, why are we not taking away subsidies for all corporations?
We should take subsidies away from corporations, not industries. Let me explain, we need to subsidize nascent industries i/e biofuels, electric vehicle production etc, we don't need to subsidize large corporations that have large R&D departments. Subsidizing small companies in nascent industries is OK, subsidizing GE on windmills is idiocy.