The formation of petroleum, also known as crude oil, is a complex process that takes place over millions of years under specific geological conditions. It begins with the accumulation of organic matter, primarily the remains of microscopic marine organisms like plankton and algae, on the seabed. As these organisms die, they settle to the bottom and are covered by layers of sediment, such as sand and mud.
Over time, the increasing weight of the overlying sediments compresses the organic matter, subjecting it to high pressure and temperature. This process, along with the absence of oxygen, transforms the organic matter into a substance called kerogen. Kerogen is a complex mixture of hydrocarbons that serves as the precursor to petroleum. As the temperature and pressure continue to rise, the kerogen undergoes further chemical changes, breaking down into lighter hydrocarbons that form oil and natural gas.
The newly formed oil and gas, being less dense than the surrounding rock and water, migrate upward through porous rock formations, such as sandstone. However, their upward movement is often halted by impermeable rock layers, known as cap rocks, which trap the hydrocarbons in underground reservoirs. These reservoirs, where oil and gas accumulate, are the target of drilling operations to extract these valuable fossil fuels.
