WELLOG                         Pechelbronn


Revised 10-17-2006


© 2004 – 2006  WELLOG



It began in Paris France, 1876, when Paul Schlumberger met Marguerite De Witt, granddaughter of Francois Guiznot, a famous French historian and statesman. The father of Paul Schlumberger was Nicolas Schlumberger, the family patriarch, entrepreneur, and inventor in the textile industry.  Five sons and one daughter were born into the Schlumberger family. Two sons, Conrad and Marcel Schlumberger, born with the ambition to prospect and apply pure science in combination with their frugal entrepreneurial skill moved electrical prospecting and the science of geophysics into the 20th century.


“Crisscrossing an area in an old, light truck”…


“Conrad would climb up beside the driver, Marcel and an engineer (fresh out of school) would pile into the back with the equipment, their legs dangling… One planted the pegs, another dragged the cables, the third took the measurements…. Notebook in hand, Conrad made his observations…”


“The weaker voltages forced him to follow the movement of the potentiometer needle with a magnifying glass…”


“The men would return home covered in mud, dead tired…”


“What was needed was to replace the stakes on the surface with sondes at the bottom of the hole so as to explore their walls.”


Note: The word ‘sondes’ refers to the cylindrical logging tools used for well logging.


“Taking measurements in boreholes was a logical and technical extension of surface electrical prospecting.”


“In August, 1927 Henri Doll settled in Pechelbronn, France.”


“My father told me to imagine an eye, which, traveling up and down the length of a borehole, would recognize the nature of the different strata traversed by the bore.”


“The equipment, however, could not have been more rudimentary; roughly, it included three conductive cables spliced together with insulating tape every five meters, a sonde weighted with lead, a winch operated by hand, storage batteries, and a potentiometer.”


Note: the “potentiometer” was an instrument used for measurement of “electrical potential” (voltage) similar to an analog voltmeter.



Henri Doll, 48, the youngest, and the Schlumberger brothers, Conrad and Marcel, after several failed attempts, and cable breaks, made a great leap forward in the history of geophysics…


“A few days later, on September 6, 1927, at an inn in Woerth, a dinner marked a memorable date – the date of the first electrical measurements taken in a borehole… This was the birthday of “electrical coring”.


“The term electrical coring was adopted in 1927 by analogy with mechanical coring… the expression was replaced in 1933 by electrical logging, the term now in use throughout the petroleum industry.”


“The term log represents a strip of paper or film on which the measurements are recorded as curves (diagrams) in terms of depth, as a marine log measures the distance traveled by a ship in time.”




 Quotations are from the book “The Schlumberger Adventure” by Anne Gruner Schlumberger. Anne Gruner Schlumberger was the daughter of Conrad Schlumberger. Marcel Schlumberger was her Uncle.  Henri Doll was her husband.


Learn more about electric logging (E-Log) and modern advancements in this method on this website!