HW - Modeling trapping and migration of hydrocarbons

Soundtrack excerpt:
Plate tectonics and applied geology (2-A)
'Plate tectonics and hydrocarbon research'

Scientific issue:
The formation of a hydrocarbon reservoir requires trapping the resource in a reservoir rock.
One aspect of geology applied to oil exploration is to understand the conditions of hydrocarbon migration within geological formations and those of their trapping.

Procedure:
Hydrocarbons originate in source rock. They are formed from kerogen, a mixture of water, CO2, carbon, and hydrogen from the decomposition of organic matter.
However, in the rock, hydrocarbons take up more space than kerogen. Gradually, they are expelled into water-saturated rock layers surrounding the source rock. Lighter than the water contained in these rocks, gas and oil (another name for petroleum) tend to slowly and continuously rise to the surface: this is migration.
This migration is an ascent through rock layers. Hydrocarbons gather when they encounter rocks that allow fluids to flow. When these large reservoirs are covered by impermeable rocks, the rise of hydrocarbons is stopped: an oil field is formed.