Conrad Schlumberger

Conrad Schlumberger was a French physicist who pioneered the use of electrical resistivity measurements to locate oil and mineral deposits underground. Building on surface resistivity survey techniques he developed from 1912 onward, he worked with his engineer brother Marcel to extend the method down a borehole, and on September 5, 1927 the brothers recorded the first electrical resistivity log of an oil well, near Alsace, France, a method that let geologists read the rock layers a well had passed through directly from electrical measurements rather than from drill cuttings alone. In 1926 the brothers founded the Societe de Prospection Electrique, the company that grew into Schlumberger Limited, which became one of the world's largest oilfield services companies.