1. HGS Petroleum Exploration Methods What Geologists and Geophysicists
do to find oil and gas
Cerro Azul #4 blow-out,
Veracruz, Mexico
February 1916
Houston Geological Society
Academic Liaison Committee

2. HGS Petroleum Exploration Methods Part II: Petroleum System: Source
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3. Houston Geological Society Academic Liaison Committee

4. Source: Oil is produced from “source rock”
Oil is formed in sedimentary rocks that contain large quantities of organic material. Most of the world’s oil is generated from rocks containing algae, an aquatic plant
Houston Geological Society
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5. Source: Oil is produced from “source rock”
Oil forms from organic matter that is "cooked" deep within the earth for long periods of time at low temperatures.
Fossil organic matter is called kerogen
Houston Geological Society
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6. Source: Oil is produced from “source rock”
Houston Geological Society
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7. Petroleum System A Dynamic Entity 1) Early Generation
Spill Point
Seal Rock
(Mudstone)
Reservoir Rock
(Sandstone)
Migration from
‘Kitchen’
1) Early Generation
2) Late Generation
Gas displaces all oil
Gas beginning to displace oil
Displaced oil accumulates
Houston Geological Society
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8. Accumulation and Preservation
Petroleum System: Timing is Critical
Trap Must Be Available Before/During Migration
Trap
Accumulation and Preservation
Processes:
Generation
Migration
Elements:
Source Rock
Migration Avenue
Reservoir and Seal
Houston Geological Society
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9. HGS Petroleum Exploration Methods Part II: Petroleum System: Reservoir
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10. Reservoir: Oil is stored in “reservoir rock”
Oil fills the pore-space between grains
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11. Reservoir: Oil is stored in “reservoir rock”
Sand grains are white, pore space is blue
Porosity = 26%, permeability = 2434 md
Houston Geological Society
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12. = Less Space for Petroleum
Reservoir Sandstone
Pore-Filling Cement Reduces Quality
Cement
(pink)
= Less Space for Petroleum
Houston Geological Society
Academic Liaison Committee