"We" don't get our oil from anywhere specific. Private companies like Exxon Mobil extract and refine the oil, not the United States. All that oil goes out on the open market and is purchased by whomever wants to at whatever the market price is.
There is no such thing as "we can provide our nation with the oil it needs." We as in the United States don't provide any oil to anyone anywhere, period. You're confusing the United States with China and Russia.
Oil companies will happily sell oil produced in the US to anywhere in the world, it's not promised to the US first because it was extracted from here. More refinery capacity in the US would mean more supply on the open market, which would bring prices down for everyone, not just the US. Cutting off Russia decreases supply, bringing prices up for everyone.