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Oil and gas - Coggle Diagram

- - - - destruction
        
        most organic matter eaten, oxidised on surface
      - preservation
        
        lacking oxygen
        
        enclosed basin no ocean currents to sweep away source rock
        
        low oxygen preserve organic matter
        
        algae die and fall to seabed
        
        aerobic organisms can't survive
        
        animals can't eat organic matter
        
        can't carry out degradation
      - burial
        
        sediment deposition
        
        not too much as this dilutes organic content
        
        moving rock away from oxygen is better to reduce bacteria
        
        maturation
        
        increases overburden pressure causing temperature to increase
        
        temp determines organic matter products
        
        temp increases with depth due to heatflow from centre of earth
        
        must be buried deep enough for temp to be hot enough to generate oil
        
        40-80 kerogen window- anerobic and abiotic breakdown of organic matter
        
        oil window 100 to 150 degC breakdown C bonds and form short chains
        
        3 more items...
        
        lose H2O, CH4, Co2, O
        
        diagenesis
      - production
        
        mostly generated by algae and bacteria
        
        generally close to land
        
        shallow, warm water
        
        close to rivers - bring nutrients
  - - - algae
      - oil shales
      - lipid rich
      - low O:C atomic ratio, high H:C atomic ratio
    - - phyto and zooplankton
      - oil and gas
      - lipid rich
      - marine source rocks
    - - terrestrial plants
      - gas - coals
      - humic
      - high O:C atomic ratio, low H:C atomic ratio
- - - - coal
      - diesel, fuel, hydrocarbons
    - - road surfaces
  - - - index of how heavy a crude oil is
        
        based on specific gravity index
      - 50s
        
        lightest chains
        
        shortest hydrocarbons
        
        most volatile
        
        gas-liquid
      - 30s-40s
        
        average constituents of fuel
        
        mostly liquid
        
        ideal for refinaries
        
        starts to evaporate at very low temperature
        
        easier to extract and more commercial uses
        
        clear
      - below 15
        
        heaviest and longest chains
        
        need cracking for commerical
        
        hard to process, lots of waste
        
        more energy to produce light chains
        
        not energy efficient or cost effective
        
        heavy and dark
        
        bitumin
        
        solid
    - - cycloalkanes, alkanes, arenes
      - compounds with SON
      - different oils different composition based on organic material derived from and changes over time