Formation of Oil and Gas

Oil and natural gas are fossil fuels formed from the remains of ancient plants and tiny marine organisms over millions of years. Process of formation 1. Accumulation of organic matter Dead plants, algae, and small marine organisms settle at the bottom of seas, lakes, and oceans. 2. Burial by sediments Layers of mud, sand, and other sediments cover the organic matter. 3. Increase in pressure and temperature As more sediments accumulate, the organic material is buried deeper. Pressure and temperature gradually increase. 4. Conversion into hydrocarbons Over millions of years, heat and pressure transform the organic matter into kerogen and eventually into crude oil and natural gas. 5. Migration Oil and gas move through porous rocks until they reach a layer of impermeable rock. 6. Trapping Oil and gas become trapped beneath impermeable cap rocks, forming a petroleum reservoir. In simple form

Organic remains → Burial → Heat & Pressure → Oil & Gas → Migration → Trapping → Petroleum reservoir Oil generally forms at lower temperatures than natural gas; with increasing temperature and burial depth, organic matter can produce more gas.