Petroleum is extracted in Nigeria by drilling. This involves drilling deep into the earth's crust to locate and extract crude oil which is then transported to refineries for processing into various products such as gasoline, diesel, and jet fuel. Drilling for petroleum in Nigeria is typically done on land or offshore in the ocean using drilling rigs, which are large machines designed to drill deep into the earth's surface. Once the oil is extracted, it is transported through pipelines or by tanker trucks to refineries for further processing. Petroleum is not mined or dredged like other natural resources such as metals or minerals.