OIL

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  • Created by: wardk
  • Created on: 30-06-16 19:40
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  • OIL
    • Formation
      • Dead Tropical Marine Plankton
      • Anaerobic conditions prevents complete decomposing
      • Heat +Pressure causes chemical change of Hydrocarbons into smaller molecules
        • Solids (high viscosity) into liquids (low viscosity) +Methane
    • Extraction
      • Crude oil found in geological structures where liquid oil can flow through permeable rock and collect in the pores between porous rock particles
      • Natural gas above and/or water beneath creates a pressure which forces the oil to the surface when a pipe is drilled down
      • Pipeline  up to 10km deep through impermeablerock cap to reservoir rock underneath
    • Availability
      • > 5km below surface is difficult to reach as friction increases so pumping fluids down becomes hard. >2km beneath water is hard to exploit as anchoring the floating rig is difficult
      • Oil shale reserves are much greater  than crude oil however they are solid hydrocarbons (so cannot flow to the surface ) and need to be quarried or heated underground which is expensive.
      • Reserves are depleting as it is  non renewable, finite and very high demand. Many oil fields are too mall to be exploited profitably.
    • Technology
      • Primary Recovery: the use of natural pressure to force oil to the surface, extracting 20%
      • Secondary Recovery: involves pumping down natural gas or water to maintain pressure, increasing total recovery to 40%
      • Tertiary Recovery: involves using solvents, steam or detergents to make the oil less viscous, flowing more easily, rate increased to 60%
    • Transport  & Storage
      • Normally via pipeline, railway, truck/tanker or ship from mine site to refinery
        • Pipelines require significantly less energy to operate &shave lower carbon footprint
      • Stored in above-surface tanks ready for transport
    • Uses
      • Vehicle Fuels e.g. Petrol, Diesel
      • Heating Fuels e.g Propane, Butane
      • Making Plastics
    • Economic Issues
      • Costs of rig, drill, pumps, steam, detergents...pipelines, tankers, ships, railway... above surface tanks and refineries
    • Trade
      • Reserves are not evenly distributed so although MEDCs use over half of the worlds oil production only a small % is home  produced
      • Most reserves are in the Middle East  so transport costs are very expensive
    • Environmental Impact
      • Combustion and Flaring of surplus mathane on rigs to reduce explosion risk =Air Pollution
      • Oil spills from rigs, tankers and pipelines + oil based drilling mud used to lubricate drill pipes may pollute groundwater, rivers and sea
      • Habitat Damage due to deep mine subsidence and pipeline construction, reduced by soil replacement/replanting
      • Seismic surveys can harm whales

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