In 1912, the French physicist Conrad Schlumberger could be found kneeling on the ground of his family’s estate in Normandy, strategically placing wired electrodes in the soil. He was performing conductivity tests to detect the buried ruins of a medieval abbey destroyed there during the French Revolution. But the experiment had a broader purpose: proving that electric instruments could be used to reveal and map underground structures from the surface. Schlumberger’s approach worked, and it turned out to be a remarkably effective tool for a more lucrative enterprise: finding oil.
Conrad and his brother Marcel Schlumberger went on to create the first well logs—using electric cables for subsurface readings, producing outputs that resembled EKG heart monitor readings. The method became the backbone of modern geophysical prospecting, and supercharged the growth of a burgeoning oil and gas exploration industry worldwide. In 1926 the brothers founded the Société de Prospection Électrique (Electric Prospecting Co.). That company—eventually Schlumberger and now SLB—rapidly expanded into Venezuela, the United States, and the Soviet Union. By the end of the 1930s, Schlumberger had moved into the Middle East, more than 20 years before the formation of OPEC.
