There are approximately 100 countries that produce crude oil. Globally in 2017, the top five crude oil producing countries were:

• Russia (13%)
• Saudi Arabia (13%)
• USA (12%)
• Iraq (6%)
• Iran(5%)

The majority of the crude oil produced in the U.S. is from the following states.

• Texas: 38%
• North Dakota: 11%
• Alaska: 5%
• California: 5%
• New Mexico: 5%

Additionally, in 2017 about 18% of U.S. crude oil was produced in the federally administered areas of the Gulf of Mexico.

Petroleum is not a renewable commodity and must, therefore, have a finite limit to the amount that can be recovered. Estimates of how long either national or global oil reserves will last, given both technological and economic limitations to extraction, is an important aspect of the study of petroleum supply.

The term "peak oil" refers to a point in time when the rate of extraction of oil from available resources reaches its maximum and begins a decline toward a terminal end point. There can be a number of reasons contributing to this limit, but most considerations boil down to exhaustion of the available supply that can be extracted at a cost which is profitable.

On a global level, there is ongoing debate regarding the timing of peak oil in Saudi Arabia and other OPEC countries. The efforts to predict such events are complicated by the lack of reliable data from OPEC countries regarding their current petroleum reserves and the historical rates of decline in those reserves.