It did not take long for Paul Schlumberger to realise that his two sons – Conrad, the eldest, and Marcel, the youngest; an engineering graduate from the French engineering school École Centrale de Paris – complemented each other well.
In 1919, after the First World War, during which Conrad broke off his research, Paul Schlumberger granted the then substantial sum of 500,000 francs as part of an agreement. A single extract of this agreement sums up Paul Schlumberger’s paternal state of mind : « The money I have granted to my sons is my way of contributing to a scientific and secondarily practical work that I believe to be of the utmost value and in which I am interested. Marcel will provide his remarkable engineering skills and sense of reality to Conrad, who, in turn will be the expert physicist. I will support them. ».

Bolstered by the family’s enterprising spirit, Conrad and Marcel founded the Société de Prospection Electrique in 1926.

On 5 September 1927, a sizeable historic test was carried out in one of the wells of the Pechelbronn oil field. It led to the birth of “electrical logging”, which was to become a renowned technique within the global oil industry.

The two globe-trotting brothers travelled to places such as North Africa, Venezuela, the USSR and the USA, exploring for oil and laying the foundations for an international business which continues to offer its services to the global oil and gas industry.