OIL AND GAS MIGRATION AND ACCUMULATION

MIGRATION

  1. porous, coarse-grained, permeable rock that insoluble in organic matter
  1. kerogen release from source rock
  1. transport through narrow pores of fine grain SR
  1. oil expelled from SR through wider pores & more permeable porous rock
  1. petroleum may migrate through 1 or more carrier SR with same porosity and permeability
  1. trap in impermeable barrier

ACCUMULATION

  1. all pores in subsurface are water saturated
  1. petrol compound's movement take over within porosity
  1. activate the water flow
  1. occurrence of the aqueous phase
  1. 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