PETROLEUM SYSTEM
MIGRATION
TRAPS
SECONDARY
TERTIARY
PRIMARY
The movement of oil and gas out of the fine-grained source rocks into the coarse-grained reservoir rocks.
Distance is usually short only as far as needed
The richer the source rock in oil prone kerogen, the more rradily it expels oil.
The movement of fluids within reservoir rocks leading to oil and gas segregation
as a result of bouyant and hydronamic processes moving oil
Possibilities of mixing
Initial pathway dendritic until path of least resistance established
Movement of oil and gas after formation of recognizable accumulation
includes leakage, seepage, dissipation and alteration of petroleum
Driven by bouyancy
Petroleum Traps
Stratigraphic: formed by lithological changes
Structural: formed because of a deformation in the rock layer that contains hydrocarbons
Structural Traps
Fault
Anticlinal
ALTERATION
Changes in petroleum composition due to biodegradation
Changes in petroleum composition due to thermal alteration
Other alteration processes leading to compositional changes in petroleum
CAP ROCK: prevents petroleum from leaking out of a trap