Paper crude oil is a kind of personal certificate-type crude oil. Investors buy and sell "virtual" crude oil on the book according to bank quotations. Individuals operate by grasping the trend of international oil prices and earn the fluctuation difference of crude oil prices. Paper crude oil will be priced in US dollars, and the investment targets are single-month and bi-month contracts in the WTI crude oil futures and Brent crude oil futures markets. However, like paper gold and paper silver, physical delivery is not possible and can only be settled in cash.