petroleum also know as hydrocarbon due to its mixture of hydrogen and carbon compounds, originating from small plants and animals which lived in ancient seas and waterways. The remains of these accumulate with soil particles carried by wind and water, building up thick layers of sediments. Over millions of years, these layers of sediments were buried and slowly turned into rocks. Over time, the high temperature, high pressure and bacteria within the rock layers transformed the animal and plant remains into petroleum. millions of years later, movements of the earth's crust bent and broke the rocks with extreme force, creating "traps". petroleum in the "source rock" (so called for being the source petroleum) was squeezed upwards, entering empty traps in porous rock such as sandstone or lime stone.