Airborne resistivity: mapping subsurface stratigraphy from the air

Electrical resistivity is one of the fundamental physical properties of the subsurface Earth and, from the perspective of many explorationists, one of the most important. Conrad and Marcel Schlumberger, for whom the largest oilfield service company in the world is named, pioneered the concept of using downhole electrical measurements to map subsurface rock formations in 1926. Since then, resistivity measurements have been captured for almost every well drilled in the world as part of the standard well logging suite. The value added by the traditional oilfield resistivity measurement comes from the fact that hydrocarbon- rich reservoir rocks tend to be electrically resistive while water-filled zones are not. Powerful as this type of resistivity information is, one significant flaw exists with the logging technique – it requires a well to be drilled.