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Which geologic processes can create petroleum traps?

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petroleum production A semisubmersible oil production platform operating in water 1,800 metres (6,000 feet) deep in the Campos basin, off the coast of Rio de Janeiro state, Brazil.

Geologic processes create petroleum traps by deforming rock layers or altering their composition, effectively blocking the migration of oil and gas and causing them to accumulate in reservoirs. These traps are primarily categorized into two types:12

Structural Traps

These are formed by tectonic events that deform rock units:1
* Folding: The most common structural traps are anticlines, which are upfolds of strata created by lateral pressure or the compaction of sediments over topographic highs.12
* Faulting: A fault trap occurs when rock fractures and shifts, bringing an impermeable layer into contact with a permeable reservoir rock, thereby creating a barrier.12
* Salt Domes: These form when salt masses move upward from deeply buried evaporite beds, arching or faulting the surrounding sedimentary rock to create traps along their flanks or tops.13

Stratigraphic Traps

Unlike structural traps, these are formed by variations within the rock strata themselves. They occur due to changes in the porosity or permeability of the reservoir rock, shifts in the types of rocks deposited, or the natural termination of the reservoir rock layer.2