Conrad Schlumberger (2 October 1878 in Guebwiller – 9 May 1936 in Stockholm) and Marcel Schlumberger (21 June 1884 in Guebwiller – 9 May 1953 in Val-Richer) were brothers from Alsace, France (Conrad a physicist -graduated from École Polytechnique (France) in 1900- and Marcel, an engineer graduated from École Centrale Paris in 1907). In 1912, Conrad conceived the revolutionary idea of using electrical measurements to map subsurface rock bodies in order to acquire information about the nature of the rock (chalk, sandstone, granite,etc.) and the presence of hydrocarbons. In 1919, Marcel began working with his brother and in 1920 they opened their first office in Paris. In 1927, the Schlumberger brothers produced the first measurements (Electric Log) of an oil well in France. These ideas were very successful, and they founded the Société de Prospection Électrique in 1926 and Schlumberger Well Surveying Corporation (now Schlumberger Well Services) in 1934. In 1956, Schlumberger Limited was formed in Curaçao as the holding company. They made measurement tools, and sold their services to oil companies who wanted to know where it was worth completing a well. Their principle laid the foundation of wireline logging, a technology still widely used in modern petroleum engineering.
