A Brief History of Schlumberger

1870s-1910s: An early passion

The world’s first well logging company had its origins in the Alsace region on the French-German border, where Conrad Schlumberger (born 1878) and his brother Marcel (born 1884) grew up as part of a family of six children. Their father, Paul Schlumberger, was descended from a wealthy cotton-weaving family; their mother, Marguerite de Witt, was a political activist and campaigner for women’s rights.

Conrad and Marcel both wanted to be scientists and their father supported their ambition. The brothers were sent to Paris to further their education. Conrad became a physicist, graduating from the École Polytechnique in 1900, before studying at the École des Mines. Marcel became an engineer, graduating from the École Centrale Paris in 1907.

Conrad took an early interest in earth sciences and developed a particular interest in prospecting for metal ore. He realized that metal ores should be distinguishable from their surroundings by measuring their electrical conductivity, as ore-bearing rock would be more conductive than what was around it. If an electric field could be generated below ground, voltage measurements at the surface could be mapped to show lines of equal potential—equipotential curves—which could then be compared with what would be expected if no ore were present. Any differences could indicate the presence of mineral deposits.

Now, he needed to put the theory to the test.

In 1910, Conrad Schlumberger began teaching physics at the École des Mines, where, the following year, he started tests on what was to become known as wireline logging, first in the lab and then out in the field.

In 1912, using very basic equipment, he recorded the first map of equipotential curves at his estate near Caen in Normandy, before extending his surveys to iron mines in the area. The resulting mapping of equipotential curves not only confirmed the method’s ability to detect metal ores but also revealed features of the subsurface structure, such as bed boundaries and the direction of formation layer dips.

That Schlumberger’s technique could provide this extra information was highly significant, as it meant that it might be useful for locating subsurface structures that could form traps for minerals such as oil and gas.

However, progress was severely disrupted by World War I. Conrad served as an artillery officer from 1914-18, before returning to his research.

He received strong support for his work from his family. In 1919, his brother Marcel began working as a partner with Conrad, initially in Normandy. Meanwhile, their father, Paul, provided them with fresh funds to take the research further—on the condition that scientific gains must take precedent over financial benefits.

However, Conrad had long been aware of the business potential of his research and had patented his discoveries in several countries, while studying how his electrical prospecting method could be turned into an industrial application.

The next decade saw that commercial potential starting to be realized.

1878

Conrad Schlumberger born in Alsace

1884

Marcel Schlumberger born

1910

Conrad Schlumberger begins teaching at the École des Mines, Paris

1912

Conrad Schlumberger conceives the revolutionary idea of using electrical measurements to map subsurface rock bodies

1919

Marcel Schlumberger begins working with his brother Conrad

1920s: The First Well Log

It took until 1920 for Conrad Schlumberger to publish the results of the experimental surface resistivity measurements he had carried out since 1911.

In the same year, Conrad and Marcel opened their first office at 30 rue Fabert in Paris.

Conrad’s focus on making geophysical measurements became all-consuming now, prompting him to resign his professorship at École de Mines, Paris in 1923.

Conrad and Marcel spent the next three years conducting geophysical surveys in Serbia, Canada, South Africa, Congo and the USA, as well as Romania, where they made the first mapping of an oil-productive salt dome using electrical prospecting.

In 1926, they created the Société de Prospection Électrique, or “Pros” as it was nicknamed—the forerunner of the Schlumberger company. Initially, the firm carried out surface prospecting for the metal ore mining industry but gradually extended its activities to embrace exploration of possible oil-bearing structures.

To better understand measurements made at the surface, the Schlumberger brothers needed to incorporate resistivity information from deeper formations. Conrad had the idea of measuring resistivity directly with an electrical probe, or sonde, run into boreholes drilled through the formations.

The first attempt to do this was made on September 5, 1927 by a team led by experimental physicist Henri Doll, Conrad’s son-in-law. Measurements were taken from an electrical sonde at various discrete depths in a 500-meter-deep well in Pechelbronn in the Alsace region of France. A new term was coined to describe the results of this multi-depth survey: it was called an electrical resistivity well log.

This first log was little more than a simple hand-plotted graph, but it marked a turning point in the history of oil exploration. Before then, engineers and scientists had to rely on core samples or cuttings brought up from boreholes to assess the composition of subsurface rocks. But the indications these gave were highly unreliable and frequently missed oil zones. The log showed that electrical measurements taken in boreholes could help identify the geological formations around them. It effectively enabled people to “see” what was down the well—and because the resistivity recordings proved to be repeatable in neighboring wells, it was possible to enable precise correlation of formations across an entire field.

International demand for the process, also known as “electrical coring,” grew rapidly. By 1929, sub-surface logs were being run in Argentina, Ecuador, India, Japan, the Soviet Union, Venezuela and the USA.

More patents were filed around the world, ensuring that the intellectual property of Schlumberger products was secured early.

1920

The Schlumberger brothers open their first office at 30 rue Fabert in Paris

1923

The Schlumberger brothers begin conducting geophysical surveys in Romania, Serbia, Canada, Union of South Africa, Belgian Congo and the USA
Mapping of the first oil-productive salt dome by electric prospecting in Romania

1926

Formation of Société de Prospection Électrique (Pros), the precursor of Schlumberger

1927

Henri-Georges Doll joins the company, initially part-time
Doll and his team record the first electrical resistivity well log in Pechelbronn, France

1929

Subsurface surveying is carried out in Argentina, Ecuador, India, Japan, the Soviet Union, Venezuela and the USA
The USA’s first ever well log is performed in Kern County, California