Modern use began in 1816 in Baltimore, MD gaslights. First commercial oil well in 1859. Normally, crude oil, which is more viscous is pumped out and later converted to various products at refineries. Finding Petroleum Look for source rocks , rocks that originally had organic material. Find reservoir rocks , rocks that contain petroleum in their pores, much like an oil aquifer.
Sandstones make good reservoirs.
Kerogen in form temperatures never high enough to form petroleum. If profitable to extract, oil shale could supply US needs for the 500 years. Coal Most abundant fossil fuel. Largest coal field is in Antarctica. Energy comes from energy stored in plants that were buried millions of years ago.