In 1900, Conrad Schlumberger obtained a degree in Physics from the École Polytechnique with subsequent studies at the École des Mines. In 1907, his brother, Marcel, obtained an Engineering degree from the École Centrale Paris. Working together, with Conrad as the theorist and Marcel as the practical tool developer who made his brother’s ideas work, they invented the technology known today as ‘logging.’ They discovered that by imposing an electrical current between two electrodes placed far apart in the earth, equipotential lines could be drawn that were symmetrical and concentric, except when the potential encountered a body of highly-resistant ore beneath the surface. The Schlumberger brothers used this knowledge to prospect for iron ore in France, proving their theories in the family bathtub filled with sand, demonstrating how they could find coins hidden in the sand merely by observing the distortion of the equipotential lines in the electrical field they established.
In the early 1920s, Marcel and Conrad turned their focus from metallic ores to hydrocarbon deposits, proving they could identify and quantify oil and gas bearing reservoirs beneath the surface. They re-engineered their apparatus into an electrode-bearing sonde, which could be deployed into a wellbore at the end of an insulated electrical cable. In 1927, the first electric log was run in the Pechelbronn Oilfield in France, clearly identifying the depths of oil-bearing sands.
Following this technological breakthrough, the brothers took their invention around the world, logging wells in Russia, Canada, the United States, Romania, India, Algeria, Spain and Venezuela. They faced intense skepticism from geologists and wildcatters. Their measurement apparatus was termed ‘Le Boîte Magique’ (the Magic Box), but its discoveries proved to be accurate and the skeptics became believers.
For almost a century, the many inventions of the Schlumberger brothers led the world in its search for energy. Schlumberger was among the first companies offshore, making discoveries in the Gulf of Mexico, the Caspian Sea, and offshore California. The measurements made by a succession of Schlumberger logging tools helped remove the uncertainties of exploration, augmenting seismic surveys and reducing drilling risk by orders of magnitude.
The brothers Schlumberger founded Compagnie Générale de Géoophysique (CGG) and became a leader in marine seismic with the acquisition of Geco, followed by Prakla Seismos, and finally Western Geophysical. The offshore techniques developed by these companies have been instrumental in identifying and characterizing deep and ultra-deep water discoveries worldwide. Of particular importance was the perfection of subsalt imaging and processing that let to many of the most recent developments in the Gulf of Mexico and offshore Brazil.
Adaptation of downhole measurements invented by the Schlumberger brothers to explore the most challenging offshore frontiers has played a major role in reduction of drilling, completion and production risk.
Because of the huge upfront investment required to explore and drill offshore, it could be argued that absent the accurate, log data, many offshore prospects might never have been developed. This was particularly true when geologists encountered vast reservoirs of oil in low-contrast sediments – discoveries only made possible through the application of high-resolution logging instruments that could discriminate and quantify the thin oil-bearing strata.
The pioneering work started by the Schlumberger brothers and perpetuated by the company they founded has played and is still playing a key role in the discovery and development of offshore plays worldwide. Their efforts and the application of their technology in the development of offshore hydrocarbon have truly earned them the title of pioneer.