GLG211%2C+W10%2C+L1%2C+Fossil+Fules
Page 1: Learning Objectives
Understand the Formation Process
Describe how heat, pressure, and time convert organic matter into fossil fuels.
Identify Fossil Fuel Types and Characteristics
Differentiate coal, crude oil, and natural gas based on composition and properties.
Describe Fossil Fuel Geochemistry
Summarize the geochemical processes that determine fossil fuel composition.
Examine Global Distribution and Reservoirs
Identify major fossil fuel regions and the geological factors behind their accumulation.
Page 2: Learning Objectives
Understand Extraction Methods
Explain how fossil fuels are extracted and the geochemical impacts of extraction.
Evaluate Environmental Impacts
Assess the environmental effects of fossil fuel extraction and use.
Analyze Energy Production and Use
Discuss the role of fossil fuels in energy production and their efficiency.
Page 3: Fossil Fuels: 3 Fuels, 3 Physical States
Hydrocarbon Molecules:
Natural Gas: Gas, primarily methane, significant for lower carbon emissions.
Crude Oil: Liquid, source of transportation fuels and petrochemicals.
Coal: Solid, primarily carbon-based, significant for electricity but high carbon emissions.
Page 4: Fossil Fuels: Different Origins
Natural Gas and Oil
Formed from burial, heat, and pressure on ancient marine organisms like plankton and algae.
Coal
Originates from terrestrial plant material in swampy environments, through compaction in peat bogs.
Page 5: Key Terms
Petroleum: Natural mixture of hydrocarbons in liquid, gas, or semi-solid forms.
Crude Oil: Unrefined petroleum consisting mainly of hydrocarbons and impurities, refined into fuels.
Natural Gas: Mostly methane, used for heating, electricity, and chemicals.
Kerogen: Solid organic material in sedimentary rocks transforming into oil and gas over time.
Page 6: Locations of Natural Gas and Oil
Sedimentary Basins
Major deposits found in:
Middle East: Saudi Arabia, Iraq, Iran
North America: Gulf of Mexico, Permian Basin, Western Canada
Russia/Central Asia: West Siberian Basin
Africa: Niger Delta, Angola, Algeria
South America: Venezuela, Brazil (offshore)
Unconventional Sources
Shale formations, tar sands, and deepwater fields.
Page 7: Process of Formation
Organic debris settles with sediment, undergoes transformation under heat and pressure to form kerogen, then oil, and finally natural gas.
Majority of oil deposits from Mesozoic Era (Jurassic and Cretaceous periods).
Page 8: Kerogen Formation
Stages of Transformation
Deposition and Diagenesis: Organic material deposited in anoxic conditions.
Catagenesis: Burial heat leads to thermal decomposition; forms hydrocarbons.
Metagenesis: Further breakdown resulting in methane production.
Page 9: Conditions Leading to Formation
Organic Matter Type: Algal, mix of algae and terrestrial plants, woody plants.
Temperature: Oil formation (60°C - 120°C); gas above 120°C.
Pressure: Helps in compaction and hydrocarbon formation.
Time: Continuous burial leads to thermal maturation.
Anoxic Conditions: Essential for preservation and kerogen formation.
Page 10: Petroleum System
Four Elements
Source rock: Contains kerogen.
Migration path: For hydrocarbons.
Seal: Prevents leaks.
Reservoir: Holds hydrocarbons.
Page 11: Geological Features
Trap
Prevents hydrocarbon movement; can be structural or stratigraphic.
Seal
Impermeable layer preventing leakage; common rocks include shale and salt.
Reservoir
Porous and permeable rocks like sandstone and limestone.
Show
Indications of hydrocarbons in drilling.
Page 12: Examples of Geological Features
Traps
Structural: domes, anticlines.
Stratigraphic: pinch-outs, unconformities.
Seals
Shale, salt.
Reservoirs
Sandstone, limestone.
Page 13: Drilling Methods
Unconventional Wells
Horizontal drilling in low-permeability rock with hydraulic fracturing.
Conventional Oil Wells
Vertical drilling in more permeable reservoir rock.
Page 14: Hydraulic Fracturing (Fracking)
Process involving water and sand at high pressure to open fissures, increasing flow.
Page 15: Natural Gas Composition
Mainly alkanes; dominant component is methane (CH4).
Other components include ethane, propane, and butane.
Page 16: Natural Gas Chemistry
Alkanes: saturated hydrocarbons with the general formula CnH2n+2.
Page 17: Key Characteristics of Alkanes
Saturated Hydrocarbons: only single bonds.
Non-Polar: do not mix with water.
Straight-Chain or Branched: variations in structure.
Physical Properties: change with carbon number.
Page 18: Chemical Properties of Alkanes
Less reactive; undergo combustion to produce CO2 and H2O.
Page 19: Importance of Alkanes
Energy Sources
Alkanes, particularly methane, are efficient fuel sources due to high energy release.
Clean Burning
Produce less CO2 and pollutants compared to other fossil fuels.
Page 20: Methane Combustion Reaction
CH4 + 2O2 → CO2 + 2H2O + Energy; indicates energy release during combustion.
Page 21: Heat of Combustion
Standard enthalpy change of combustion is always negative, indicating exothermic reactions.
Page 22: Clean Burning of Methane
Simpler structures lead to cleaner combustion, with fewer pollutants produced.