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At what depths and temperatures does the oil window usually occur?

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Multiple large offshore petroleum oil rigs with cranes and equipment stand in the ocean, connected by walkways above the water. — petroleum Liquid petroleum (crude oil)—which is refined into gasoline, diesel, heating fuels, asphalt, plastics, and other useful chemical compounds—is often extracted from the ground using a series of drills and pumps.

The oil window is the specific subsurface environment where petroleum compounds are generated from kerogen through thermal degradation. This process typically occurs at the following conditions:

Depths: Approximately 760 to 4,880 metres (2,500 to 16,000 feet).1
Temperatures: Between 65 °C and 150 °C (150 °F and 300 °F).1

Within this range, maximum hydrocarbon generation generally takes place at depths between 2,000 and 2,900 metres (6,600 to 9,500 feet).1

It is important to note that these parameters can vary based on the local geothermal gradient. In regions with a higher-than-normal geothermal gradient, the oil window may be found at shallower depths, though it is often narrower in such environments. Below depths of approximately 2,900 metres, the formation of wet gas becomes more prevalent, and beyond 4,800 metres, crude oil is typically no longer stable, leaving dry thermal methane gas as the primary product.1