"Petroleum reserves" refers to the estimated amount of oil that is known to exist underground and can be extracted using current technology. These reserves serve as a source of potential future oil production. Full definition
Since then the dollar is backed by international petroleum reserves and other mineral wealth. (politics.stackexchange.com)
Yet energy companies have already booked coal and petroleum reserves equal to several times that amount, and they are spending some $ 600 billion a year to find more. (dotearth.blogs.nytimes.com)
With an eye on the nation's fuel supply, the Department of Energy authorized a release of crude oil from the strategic petroleum reserve in order to help Phillips 66 get its Lake Charles refinery up and running. (oilprice.com)