Marcel Schlumberger

Conrad Schlumberger (2 October 1878 in Guebwiller (Alsace) – 9 May 1936 in ) and Marcel Schlumberger (21 June 1884 in Guebwiller – 9 May 1953 in Val-Richer) were brothers from the Alsace region of the German Empire in what is now modern France. Their inventions in the area of geophysics and well logging were the beginnings of Schlumberger Well Services and the entire well logging industry.

Conrad and Marcel were two of six children of an affluent Alsatian Protestant family. Their father, Paul, was descended from a wealthy cotton weaving family. Their mother, Marguerite De Witt, was a political activist. When the brothers were born, their native province Alsace was part of Germany. Their parents decided to send the brothers to Paris to be educated. Both Conrad and Marcel were educated at the top engineering schools in France; Conrad graduated from École Polytechnique in 1900, whereas Marcel graduated from École Centrale Paris in 1907.

Conrad initially worked as a mining engineer at Rodez and Toulouse, and Marcel pursued a career as a railway engineer before participating in the construction of the first French tanks during the first World War. In 1912, Conrad, then a professor at the École des Mines de Paris conceived the idea of prospecting for metal ore deposits by using the electrical conductivity of ore rocks to distinguish them from the less conductive surrounding country rocks. One of the first tests was performed in a bathtub which was filled with various rocks for the experiments. In 1919, the brothers signed an agreement with their father in which their father would support their scientific research. These experiments led to an electrical surface-measuring system for mineral exploration known as a "Schlumberger array."

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