Conrad Schlumberger (2 October 1878 in Gebweiler (Alsace-Lorraine) – 9 May 1936 in Stockholm) and Emile Henry Marcel Schlumberger (21 June 1884 in Gebweiler – 9 May 1953 in Val-Richer) were brothers from the region of Alsace-Lorraine, France, then a part of the German Empire. Their inventions in the area of geophysics and well logging were the beginnings of Schlumberger Well Services and the entire well logging industry.