Oil and gas migration is one of the most important though often neglected parameters in basin evaluation, play and prospect definition worldwide. Yet, all fields known are the result of hydrocarbon migration. The neglect stems mainly from an incomplete understanding of geological and physico-chemical processes involved. Modern solutions to such problems come from the field of comparative basin analysis, using an integration of geological, geophysical and geochemical data.

Vertical oil/gas migration uses faults, fractures and pore systems, while the driving forces for migration are thermal and hydraulic. Basin-wide structural analysis is required. It will lead to the prediction of open fracture systems. The directions of both lateral and vertical migration paths are controlled by basin structure.

Where vertical oil/gas migration has been a major factor in field development not only should similar accumulations be searched for elsewhere in this basin; but also, plays for oil and gas not yet migrated vertically will become the new targets. Examples are the offshore Gulf of Mexico, the North Sea (partly), parts of the Middle East, the Vienna Basin, and Hungary (partly).

Where vertical oil/gas migration has been nil or incomplete, major new reserves will be found close to potential or thermally mature source beds, like in the Paris Basin, Hungary (partly), the North Caspian/Russia, many Subandean basins from Venezuela to Chile/Argentina, the North Sea (partly), SE Australia, the Red Sea/Gulf of Suez, the Middle East (partly), Sumatra, etc.

Once vertical oil/gas migration is understood in a basin, many new plays and prospects can be realized. Hydrocarbon migration analysis, indeed, is a powerful factor in basin evaluation and new play definition.

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