3003236
Description
Mind Map by Hoa Truong, updated more than 1 year ago
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Created by Hoa Truong
over 9 years ago
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Lecture 23
- Source rock
- rocks with high TOC (total organic carbon),
algae/plankton rich, spores, pollen, land plant remains
- formed in low energy, stagnant
(no circulation), anoxic (low
oxygen) environment
- often fine-grained
- rate of
decomposition -
preserve organic
materials
- too slow- bacteria
/oxidation on surface
- too rapid- diluted by sediments
- too slow- bacteria
/oxidation on surface
- production of organic matter -
accumulation/concentration in sediments
- preserve from bacteria/oxidation
- Decomposition environment
- lake, basin, swamps, marshes,
river, delta, anoxic zones
- lake, basin, swamps, marshes,
river, delta, anoxic zones
- rocks with high TOC (total organic carbon),
algae/plankton rich, spores, pollen, land plant remains
- Generation
- source kitchen
- area where source
rocks have matured
- area where source
rocks have matured
- burial and chemical alternation of organic material - organic
matters broken into kerogen which then broken into petroleum
- Kerogen
- Lipid rich kerogen &
sapropelic kerogen
- marine organisms
- oil
- oil
- marine organisms
- Humic kerogen
- land organisms
- gas
- gas
- land organisms
- Lipid rich kerogen &
sapropelic kerogen
- Maturation process
- oil generation requires temp: 50-90 to be
mature, cease at 140-170degree (oil windown)
- controlled by temp & time
- gas generation increases above 150degree,
cease at 200-230degree (gas window)
- degree determine by kerogen colour:
darker-high temp-more mature
- source potential: not reach oil window (immature), hotter
than gas window (overmature), max. temp reached
- oil generation requires temp: 50-90 to be
mature, cease at 140-170degree (oil windown)
- Temperature
- lower limit
- Present day temperature in wells
- Present day temperature in wells
- upper limit-
max.temp
reached
- Vitrinite reflectance
- spore/pollen colouration index
- kerogen colouration index
- Vitrinite reflectance
- rock can experience different temp from present temp in
the past due to temp gradient decrease with time/ uplifted
- below 80: biodegradation:
bacteria destroy oil
- lower limit
- Burial history
(geohistory of basin)
- model, evaluate if/when source mature before
- model, evaluate if/when source mature before
- source kitchen
- Migration
- Primary
- from rock to carrier bed
(solution in water, gas, droplets,
globules, microfacturing)
- from rock to carrier bed
(solution in water, gas, droplets,
globules, microfacturing)
- Secondary
- from carrier bed (permeable
layers) - trap (buoyancy)
- affect by poresize, rock type
- from carrier bed (permeable
layers) - trap (buoyancy)
- Tertiary
- through seal (tilting,
faulting, capillary failure)
- through seal (tilting,
faulting, capillary failure)
- buoyancy force vs capillary pressure
- water washing
- removal of gas+light HC by
solution in moving water
- removal of gas+light HC by
solution in moving water
- Fault/seal breach
- Movement of
petroleum from
source -trap
- Primary
- Preservation
- Decrease with time as processes
(heating, lift, fold, erosion)
- Age distribution of oil fields often young
- require: little/no tectonic activity
- Age distribution of oil fields often young
- require: little/no tectonic activity
- Decrease with time as processes
(heating, lift, fold, erosion)
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