Geophysicists normally use four methods to explore the sub-surface:

seismic
electromagnetism
gravitation
magnetism

Marine seismic surveys and electromagnetic techniques are the most used, and the biggest technological strides of recent years have been made in these areas.

These methods help petroleum geologists to build up a detailed understanding of sub-surface structures. The resulting data can be used to identify possible oil and gas migration paths, estimate the geometry and size of potential traps, and predict directly the presence of hydrocarbons.

Seismic survey data are not only used to search for hydrocarbon accumulations, but are also important in developing new oil and gas fields and not least in managing production.

Petroleum exploration is a business with high levels of risk and uncertain outcomes. Knowledge and technology are key requirements for success.