Early fortunes of CGG in a volatile world

In recognition of the 75th anniversary of Compagnie Générale de Géophysique, Europe’s longest surviving geophysical services company, we publish here extracts with photos from a new history of the company. The beginning 1912-1931 It was in the summer of 1912 that the young Conrad Schlumberger, who had studied at the prestigious École Polytechnique, carried out his first electrical surveying experiments on iron-rich synclines on his Val Richer property in Normandy. Using the principle that water conducts electric current, he constructed a ‘black box’ which recorded the electric current flowing between two rods acting as electrodes. He then drew a map which he compared with topographical contour lines. Comparison of the two sets of results provided clear evidence that electrical soundings could be used to build up a picture of the vertical layering of sedimentary strata, as a function of their resistivity. The following year, he measured the natural forces created by pyrites at Sain-Bel near Lyons and at Bor in Yugoslavia. After the war, Conrad Schlumberger returned to his research and made a number of important discoveries. Some of the first involved applied geophysics: in connection with oil exploration associated with the Aricesti dome in Romania in 1923, and with mining exploration at Noranda, Canada in 1924. Two years later, he formed the Société de Prospection Electrique (SPE) with his brother Marcel Schlumberger. This company, located at 30, rue Fabert, Paris, specialized in oil and mining exploration and civil engineering. It was here that the first ‘subsurface’ drilling techniques - soon to be used worldwide by SPE-Schlumberger crews -were developed, together with themethods of prospecting used some years later by the emerging CGG. In 1927, Conrad Schlumberger experimented with electrical sampling at the Pechelbronn site, the only known French oil deposit. He used drilling rigs to conduct vertical measurements, in order to gain a better understanding of the nature of the stratigraphic layers encountered, and to record the levels that showed promise for future drilling. This was the exploration technique that came to be known as logging and was destined to have a brilliant future. A year later, the SPE had nearly 100 employees, more than half of them engineers. The economic crisis that followed the stock market crash of 1929, and the ensuing fall in oil prices, left the SPE in financial difficulties. One consequence was SPE’s merger with the Société Géophysique de Recherches Minières (SGRM) and the founding in 1931 of the Compagnie Générale de Géophysique (CGG). It is a venture that has continued to do business ever since, adapting to all of the changes and crises that have marked the history of oil.