GEOL 100 Lecture Notes - Lecture 30: Shale Gas, Kerogen, Source Rock
Document Summary
All energy sources are related to geology. Fossil fuel usage increased after the industrial revolution. 90% of us energy is produced from fossil fuels. Molecules of hydrogen and carbon; complex mixtures. Short chain (1-4 carbon)--more volatile, low viscosity. Moderate chain (5-40 carbons)--liquid at earth"s temperatures. Long chain (>40 carbons)--more dense and viscous. Require refining and distillation to separate chains of different lengths. Oil and gas = ancient plankton and marine algae. Under anoxic conditions, organic matter is preserved. Lithification forms black shale, which is a source rock. Burial of 2-4 km heats black shale. Oil and gas -- 90 to 160 degrees celsius. Gas only-- 160 to 250 degrees celsius. Leaves source rock where it was generated and migrates upward. Stops in a rock that has high permeability. On top of the high permeability rock, there has to be an impermeable rock/cap/trap rock that doesn"t let oil and gas to go through it.
