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Petroleum system: Migration & Accumulation - Coggle Diagram
Petroleum system: Migration & Accumulation
Migration
Definition :Movement of petroleum from source rock toward a reservoir
Principle : Move at different phases (buoyancy), rate of migration is controlled by properties of reservoir & carrier beds.
Constraints : Physical conditions such as T & P, permeability, capillarity, surface tension, molecular size & density. Chemical property is solubility of migrating hydrocarbons
Stages
Primary : Process of losing hydrocarbons from the source rock.
From fine-grained source rock to course-grained reservoir rock
Expulsion is upward expect when there is over pressure
Source rock to carrier bed
Tertiary : Migration to the surface, either from a reservoir or source rock (Dismigration).
Petroleum moves into a new carrier
Leakage, seepage, dissipation & alteration of petroleum as it reaches the Earth's surface
Secondary : Migration from source to reservoir which includes migration within the reservoir rock itself.
Carrier to bed
Movement of fluids within reservoir rocks leading to oil & gas seggregation
Possibility of mixing (Interactions between oil, gas and water)
Higher permeability, higher migration
Petroleum moves through continuous sands, fractures, faults & unconformities until caprock is encountered
Accumulation
Elements necessary for hydrocarbon accumulation
Reservoir Rock
Depth of burial
Gross thickness range
Sedimentary rock types
Outcrop occurences
Source Rock
Lateral continuity
Age
Thickness
Kerogen type
Depth of burial
Seal
Vertical / lateral seals
Lithology of potential seals
Presence of evaporites
Fracture system
Thermal History
Rates of burial
Rates of deposition
Paleogeothermal gradient
Tectonic history
Migration & trapping of hydrocarbon
Fractures
Controls of migration
Permeability & porosity
Controls on migration
Geological History
Main tectonic events
Episodes of subsidence
Unconformities
Paleotopography
Structural History
Dip domains
Strike & dip trends
Major faults & minor faults
Basin boundary faults
Emplacement
Possibilities of gas displacement & leakage
Mixing & homogenization over geologic time
Disturb the composition