OIL AND GAS MIGRATION AND ACCUMULATION
MIGRATION
- porous, coarse-grained, permeable rock that insoluble in organic matter
- kerogen release from source rock
- transport through narrow pores of fine grain SR
- oil expelled from SR through wider pores & more permeable porous rock
- petroleum may migrate through 1 or more carrier SR with same porosity and permeability
- trap in impermeable barrier
ACCUMULATION
- all pores in subsurface are water saturated
- petrol compound's movement take over within porosity
- activate the water flow
- occurrence of the aqueous phase
- displacement/ diffusion
single phase
O&G dissolved in water
multiphase
seperation of water and H+ phases
diff betweeen 1st and 2nd primary is on its occurrene in pores of diff size and litho
dismigration
loss of H+ from trap
movement from carrier bed to trap
2nd migration
possibility of mixing, physical, chemical and bacterial alteration
movement of oil & gas from fine grain to coarse grain reservoir.
primary migration
short distance
movement oil & gas after formation of recognizable accumulation
tertiary migration
fresh trap/ leakage to the surface
vertical, horizontal or combination of both
emplacement
gas
oil
water
will effect quality hydrocarbon
when liquid oil exposed to wide surface it become more viscous and sticky because biodegration occur