It's called refinery capacity, a combination of companies liking the profitability of prices currently and the
fact there are very few refineries now operating in the United States. You can thank Biden, the enviro's, and
big oil currently drawing as much profit as they can due to Biden's push to eliminate fossil fuels.

Bloomberg has an article on it yesterday, plus there have been numerous articles over a number of years
that you can find regarding environmentalists and Democrats shutting down new applications for refineries.