How precisely? The taxes on profits from oil & gas related businesses are complex, but I honestly (as a computer scientist unrelated to oil & gas businesses) don't understand the claims that we subsidize oil & gas production. I know that the oil & gas industry is heavily taxed and there are numerous exemptions and complications to the tax regulations for that industry just as there are for other industries, but on balance it appears that oil & gas production pays billions to the US and state governments. See [1], for example.
Thank you, the paper you cite makes clear claims: that the environmental (climate change, air pollution, etc.) impact should be priced into the cost of petroleum based fuels. The paper states that 92% of the subsidies to the oil & gas industry are because of the price of fuel doesn't reflect the societal costs related to pollution.
The interesting finding presented in the paper are:
[p. 9] "Underpricing of fossil fuels is still pervasive across countries and is often substantial, especially for coal."
[p. 9] 18% of these subsidies go to gasoline
[p. 9] "The power generation sector is the largest recipient of subsidies"
[p. 10] "By region East Asia and the Pacific accounts for 48 percent of total energy subsidies"
[p. 7] China and India together had 3.4 Million premature deaths due to air pollution in 2020 (The USA had 0.1 Million)
From an economic efficiency point of view, I can understand that prices are important, but wouldn't we have to take account of the benefits of using petroleum fuels too? Like allowing developing countries to feed their populations? They clearly can't do this with solar powered agriculture and solar powered shipping.