How do geophysical methods help find oil, natural gas, and mineral deposits?

Geophysical methods are essential tools for identifying subsurface resources by detecting anomalies—differences in physical properties between a target deposit and its surrounding rock. Because these resources often reside in specific geologic configurations, geophysicists use a combination of techniques to build a clear picture of the subsurface.12

Primary Geophysical Techniques

• Seismic Surveys: By measuring the time it takes for seismic waves to reflect or refract off underground layers, geologists can map subsurface structures. This is a primary method for locating petroleum and natural gas traps.3
• Gravity and Magnetic Surveys: Gravimeters detect density variations, such as those caused by salt domes, which often indicate oil or gas. Magnetic surveys identify anomalies in Earth’s magnetic field caused by specific rock types, helping to locate mineral deposits.45
• Electrical and Electromagnetic Methods: These measure properties like resistivity and conductivity. They are particularly effective for finding metallic sulfide ores, as these materials often conduct electricity differently than the host rock.6
• Borehole Logging: Once a hole is drilled, various sensors are lowered to measure radioactivity, density, and resistivity, providing detailed data on the composition and fluid content of the rock layers.65

By integrating these methods, researchers can effectively narrow the search area for valuable deposits.2