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:star: PETROLEUM SYSTEM: MIGRATION & ACCUMULATION - Coggle Diagram
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PETROLEUM SYSTEM: MIGRATION & ACCUMULATION
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OIL & GAS MIGRATION
(3) TERTIARY MIGRATION
movement
from
TRAP
to
Fresh Trap, SEEPAGE or Leakage (surface)
- CAP ROCKS
25%
emplacement
least porous, permeable
40%
meters to hundreds of KM in
Distance
driven mechanism
Buoyancy
drive petroleum to the surface
rate of petroleum supply
breakdown due to
FAULT
FRACTURE
(1) PRIMARY MIGRATION
- from source rocks to reservoir rocks
/
Carrier Beds
transport agents
diffusion
molecular solution
oil-phase migration
gas-phase migration
Movement
oil & gas
SHORT
in
Distance
- from fine-grained to course- grained reservoir rocks
- Driving mechanism
pressure
EXPULSION
of petroleum from source rock
the richer source rock in kerogen,
the more ready it expels oil
over pressure lead to wrong direction
no upwards
75%
(2) SECONDARY MIGRATION
Meters to hundreds of KM in
Distance
ex: continuous sands, fractures, fault & unconformity
movement from
CARRIER BED
to
TRAP
Driving mechanism
Buoyancy
cause HC to rise to top of reservoir rock
petroleum accumulation
physical, chemical & bacterial alterations
(mixing)
mineral
gases
water
25%
50%
10%
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OIL & GAS ACCUMULATION
CHANGES IN PETROLEUM COMPOSITION
BIODEGRADATION
THERMAL ALTERATION
COMPOSITIONAL CHANGES
PRECIPITATION OF ASPHALTENES
deasphalting
gravity segregation
release reservoir pressure
uplift of strata
desorption of gas
10%
migration
controlled by
PHYSICAL PROPERTIES
of sedimentary strata
Permeability
Porosity
driving force
PRESSURE
Geological
COOKING PROCESS
when source rock is heated
become 'mature'
generate petroleum
oil generated from 100°C
gas generated from 160°C
AREA mature rock as
KITCHENS
generation non-HC gases
CO2
N2
H2S