It will discourage oil production, reducing supply, driving up prices. Though, I don't know if this will affect the pump price much, initially.
Not true. Oil production is profitable and the market will ensure that the oil gets produced. Remember, the tax credit only matters AFTER the company has covered its costs and made a profit. So oil production and supply won't be affected.
The oil companies charge whatever the market will bear. That is a legal obligation on the directors of the companies. As far as I know, you could reduce all corporate taxes to zero and it won't affect oil prices, but I'm happy to be corrected on that.
according to your argument, if we tax 99.99% of oil profits then oil production will not be affected. No, it won't directly affect what they charge, but it will drive all capital away from the industry.
supply will be affected and hence so will price.
Good points if only oil companies paid that rate. However, if all companies were taxed at 99.99% of profits, oil would still be drilled as the return on capital invested in oil is better than most other industries.
To be fair, that's a bit theoretical isn't it? 13% is a long way from 99.99% and right now oil companies pay less than most even though its a more profitable industry.