There are no oil "subsidies". "Oil subsidy" is a liberal's word for "allowing oil companies to deduct their costs from their revenues" the same way all businesses are allowed to do. In other words, not paying taxes on money they didn't actually earn.
https://www.aei.org/publication/the-truth-about-all-those-subsidies-for-big-oil/
The truth is that the oil and gas industry receives the same kinds of tax treatments that every other manufacturing or extractive industry receives in the federal tax code. There is nothing uncommon or out of the mainstream of tax treatments about any of the provisions that have been repeatedly proposed for repeal.
1. A great example of just how inaccurate this depiction is applies to Percentage Depletion, which has been a feature of the tax code since 1913. Basically, Percentage Depletion is the oil and gas industry’s version of a depreciation deduction for its main asset, which is the oil and natural gas in the ground, commonly known as its reserves. Every industry of any kind is allowed a depreciation deduction on its assets under the U.S. Tax Code, but, far from being a “subsidy” for “big oil”, this tax treatment was in fact repealed for all integrated oil companies, i.e., ExxonMobil, Shell, BP, etc., in 1975, and is today available only to independent producers and royalty owners. So repeal of this extremely long-standing, completely common tax treatment would have no effect on “big oil” at all, and would in fact hit small producers and royalty owners harder than anyone else.
2. Another great example of the specious mischaracterization of these tax treatments is the Manufacturer’s Tax Deduction, more commonly referred to as Section 199. The Section 199 provision was enacted by congress in 2004 as a means of encouraging manufacturers to relocate overseas jobs to the U.S., and is in no way specific to or limited to the oil and gas industry. In fact, the oil & gas industry’s ability to take advantage of this provision has already been singled out for limitation – in 2008, Congress reduced the industry’s deduction under this provision to 2/3rds of what other manufacturing industries are allowed to deduct.
3. The tax code contains a couple of credits related to the oil and gas industry – the Enhanced Oil Recovery (EOR) Tax Credit, and the Marginal Well Tax Credit. Far from being “subsidies” to “big oil,” these tax credits are used almost exclusively by small to mid-size independent producers who tend to become the operators of marginal oil and gas fields as they age and are divested by the larger companies. The EOR credit was implemented in 1990, and the Marginal Well Credit was signed into law by President Bill Clinton in 1994.
4. Finally, let’s talk about Intangible Drilling Costs (IDCs), another feature of the federal tax code that will enjoy its 100th birthday in 2013. Basically, IDCs are the costs incurred by the oil and gas industry in the drilling of its wells. Since drilling wells is the only means of finding oil and natural gas, IDCs essentially amount to what any other industry would be able to deduct as a part of its cost of goods sold, a concept of accounting and tax law as old as the tax code itself.
Independent producers and royalty owners are allowed an election to either a) expense these costs in the year they are incurred, or b) amortize them over a 5-year period. Again, most media reports commonly characterize this as a “subsidy” for “big oil”, as does the Obama Administration. The truth is that “big oil” – the ExxonMobils, Chevrons, Shells and BPs of the world – benefit much less from this tax treatment, it having been severely limited to them by congress in 1986, and again in 1992. And the truth also is that IDCs are not a “subsidy” to anyone engaged in the oil and gas business.
Bottom line: Despite the Administration’s rhetoric that has been so widely repeated in the press, the tax treatments in question are not “subsidies” that are in any way outside of the mainstream of tax treatments commonly available to all U.S. industries. Rather than being mostly a benefit to “big oil,” the repeal of these and other oil and gas industry-related tax provisions would mainly impact smaller independent producers and royalty owners. Such repeal would serve no legitimate public policy purpose, other than to unfairly discriminate via the tax code against one of the nation’s most productive – albeit easily demonized – manufacturing industries.