Petrodollar

"The term petrodollar refers to the US Dollars earned by oil-exporting countries through the sale of their petroleum products in the global market. These dollars circulate internationally and are used for various economic and financial transactions such as imports, investments, and more. The concept became prominent in the 1970s when many oil-producing nations agreed to price their oil in Dollars, leading to a significant impact on global currency markets and trade. 

Through petrodollar recycling, oil-exporting countries reinvest their accumulated US Dollars back into the global economy, which ensures a consistent demand for the US Dollar, further strengthening its status as the world's primary reserve currency."

Source: https://blueberrymarkets.com/market-analysis/what-is-the-petrodollar/#:~:text=Defining%20the%20petrodollar,global%20currency%20markets%20and%20trade.