Schlumberger Limited (NYSE: SLB) is the world's largest oilfield services company. Schlumberger employs over 113,000 people of more than 140 nationalities working in approximately 85 countries. Its principal offices are in Houston, Paris, and the Hague.

Schlumberger was founded in 1926 by French brothers Conrad and Marcel Schlumberger as the Société de prospection électrique (French: Electric Prospecting Company). The company recorded the first-ever electrical resistivity well log in Merkwiller-Pechelbronn, France in 1927. Today Schlumberger supplies the petroleum industry with services such as seismic acquisition and processing, formation evaluation, well testing and directional drilling, well cementing and stimulation, artificial lift, well completions and consulting, and software and information management. The company is also involved in the groundwater extraction and carbon capture and storage industries.

The brothers had experience conducting geophysical surveys in countries such as Romania, Canada, Serbia, South Africa, the Democratic Republic of the Congo, and the United States. The new company sold electrical-measurement mapping services, and recorded the first-ever electrical resistivity well log in Merkwiller-Pechelbronn, France in 1927. The company quickly expanded, logging its first well in the U.S. in 1929, in Kern County, California. In 1935, the Schlumberger Well Surveying Corporation was founded in Houston, later evolving into Schlumberger Well Services, and finally Schlumberger Wireline & Testing. Schlumberger invested heavily in research, inaugurating the Schlumberger-Doll Research Center in Ridgefield, Connecticut in 1948, contributing to the development of a number of new logging tools. In 1956 Schlumberger Limited was incorporated as a holding company for all Schlumberger businesses, which by now included American testing and production company Johnston Testers.^{[citation needed]}