Energy Resources

Fossil Fuels

Daily Question

1. What sort of random events have influenced the path of evolution on Earth?

Energy an the Earth System

• Energy Resources

• Renewable versus Nonrenewable

Energy Resources - Hydrocarbons

• Our most important resources - oil & gas

• What are oil and gas?

Oil & Gas - How does it form?

• Sedimentary Basins - sediments becoming rock

• Biomass preserved as fossil carbon (kerogens) - source rock

• Source rock heated and compressed over time

• Petroleum window - oil and gas generation

• Petroleum rises through the column of rocks

Oil & Gas Reserves

• Reserves occur in sedimentary basins on every continent

• 50% of all reserves in the Persian Gulf

• Economically important accumulations of oil and gas relatively uncommon - Why?

• Mature source rock

• Reservoir Rock

– Porosity and permeability

• As petroleum is generated it rises

• To form an accumulation - must be trapped

– Traps & Seals

• Types of Traps

• Structural

– Anticlines

– Salt Domes

• Structural & stratigraphic traps

– Faults

– Stratigraphic pinch outs

• Economic accumulation = oil field

• Fluids segregated by density

Petroleum Exploration

• Seismic Surveys

– Seismic waves - travel times

Petroleum Production

• Rotary drilling rigs

• Pump jacks

Other Hydrocarbons - Coal

• Terrestrial biomass preserved as fossil carbon

• Tropical forests & swamps

• peat

• Peat is compressed and heated in a basin over time

• Heat & pressure - coal types

• Lignite, bituminous coal, anthracite

Coal Reserves

• Most of the worlds coal reserves are in North America