Henri-Georges Doll

From ETHW
Henri-Georges Doll
Henri-Georges Doll with Annette Schlumberger
Birthdate
1902/08/13
Birthplace
Paris, France
Death date
1991/07/25
Associated organizations
Schlumberger
Fields of study
Petroleum
Awards
Anthony F. Lucas Gold Medal

Biography

The original version of this article was created by Francesco Gerali, 2020 Elizabeth & Emerson Pugh Scholar in Residence at the IEEE History Center

Early Life and Education

Henri-Georges Doll was born on August 13th, 1902, in Paris. His family moved to Lyon shortly after where he was educated until high school. During World War I, his father, a Swiss citizen, served as an officer in the French Army while he lived with his brothers and mother, a native of France, who was working in a hospital. After the lyceum, he was admitted to the Ecole Polytechnique[1] in Paris, and after graduation he pursued master level studies at the Ecole des Mines.[2] In 1924, at the age of 22, while he was still a student, Doll married Anne “Annette” Schlumberger, the daughter of François Conrad Schlumberger[3] (1878-1936) (FIG 1). The latter was first Professor of physics at the Ecole des Mines of Saint-Etienne (1906-1907), then Professor of physics at the Ecole des Mines of Paris (1907-1914 and 1919-1922), where in 1912 the connection between electrical potential and the deposition of minerals in the subsoil was discovered (FIG. 2 & 3).

Pechelbronn 1927: the turning point

In 1925, Doll was hired part-time by his father in law (Henri Émile “Marcel” Schlumberger) and uncle in law's company, the Société de Prospection Électrique - Procédés Schlumberger (Electric Prospection Company - Schlumberger Processes), which from 1919, specialized in subsoil electrical prospection applied to mineral research. After graduating in 1926, he participated and distinguished himself in the massive campaign of the electrical survey of the Alsace plains, which resulted in the largest discovery of salt deposits ever made in the region. This episode boosted the credit of the Société de Prospection Électrique, which, in the same year, was experiencing hardships in its parallel core business: petroleum finding.

The destiny of the company and the career of Doll in the petroleum business had a dramatic turn in the territory of Pechelbronn, Alsatia, on September 5, 1927. In the leases of the Société Anonyme d’Exploitations Minieres de Pechelbronn, Henri-Georges Doll, Roger Jost and Charles Scheibli implemented the first experimental Carottage Électrique, or electrical (vertical, into the borehole) coring technique with success. The Société began to record electrical measurements in mine shafts and open holes in 1921 to obtain accurate resistivity data of various formations for a better interpretation of the surface observations. The shafts, pits, and tunnels of a standard mine are large enough to allow the passing through of operators and machinery. A petroleum borehole diameter section at that time was not larger than 12-18 inches. Doll used a rudimentary, partly ‘homemade’, but efficient series of cables, a hand moved winch already in use on the field, and a set of instruments including a potentiometer, three conductive cables gathered with insulating tape every five meters, a probe weighted by pieces of lead and electric batteries (FIG. 4 ). This difficult first attempt took 15 hours and allowed the crew to map the hole to a depth of 140 meters and was a stunning success (FIG. 5).

Beginning in July 1928, The Société had a crew commercially operating electrical coring methods in France; in the same year, Doll together with Eugene G. Leonardon, were establishing the Schlumberger Electrical Prospecting Methods, the New York branch of the Société (FIG. 6 & FIG 7). The petroleum geophysicist, a recent category of industrial scientists, welcomed with interest and admiration the new way of analyzing the stratigraphy of the terrains crossed by the borehole by the lining down of electric cables. The layout recorded (logged) a graphic diagram through the reading of the levels of resistivity which could detect distinct dark spots, the non-conductive underground bodies corresponding to petroleum deposits (FIG. 8 ).

In the United States, Doll developed advanced studies and improvements of electrical logging. He was the first to acknowledge the value of small voltages, the spontaneous potentials, recorded by the electrodes for electrical logging even when no electrical input current was transmitted in the subsoil. He understood that the spontaneous potentials allowed to determine the size of shale rocks from permeable conglomerates. He also developed the method to commercially exploit the borehole measurements of temperature, inclination, and dip (FIG. 9).

World War II

In 1939, Henri-Georges Doll was enrolled as lieutenant and artillery commander of the French army. After having been deployed to the Western Front at the beginning of the conflict, in March was he recalled to Paris to work on a classified tool for detecting land mines, on the basis of early prototypes developed in Poland. After the defeat of France, Doll made his way back safely to the United States and established a new company for developing and manufacturing detectors for metallic land mines on a large scale. The same company would shortly be the cradle for innovative studies, patents, and manufacturing automatic guidance and telemetry systems, industrial instrumentation of precision, photomultiplier tubes (FIG. 10), and sealed-tube neutron generators (FIG. 11).

Development and diversification in the electrical business

Henry-Georges Doll was credited to have an innate predisposition for applied science. His sterling research and development efforts took shape into the creation of innovative technology functional for underground exploration by mean of electrical impulses and sound waves, which dramatically contributed to the growth of petroleum exploration.

In 1948 he was the driving force behind the maturation and evolution of the Schlumberger applied research unit. He laid the basis for the Schlumberger Well Surveying Corporation’s research laboratory in Ridgefield, Connecticut, USA. Here he founded research groups for nuclear, sonic, mathematics/computer and log interpretation studies (Fig. 12). Here he solved one of the most pernicious obstacle in electrical data interpretation, the mixing of petroleum with base mud during the well drilling, through the experimentation of the induction logs.[4] Induction logging became very popular in the geophysics community because it could also overcome the hindrances presented to electrode methods by high-resistivity invaded zones.

In the 1950s, Doll designed the prototypes of the micro log[5] and the lateral log devices for recording; eventually he merged the two technologies into the MicroIaterolog (MLL),[6] which was used to estimate the rate of residual petroleum saturation in reservoir rocks. He is credited for the methods of resistivity determination in a permeable formation through the measurement of well borehole, depth of invasion and shoulders. In 1958, Doll achieved to develop the proximity log,[7] which was capable to detect the Rxo with higher quality by reducing the disturbance caused by the mudcake.[8]

He retired aged 65, in 1967, after a 42 year research engineer career. To celebrate his legacy, upon his retirement the Ridgefield laboratories were renamed the Schlumberger-Doll Research Center. Doll continued to work on his own establishing a small R&D firm that specialized in medical instruments for the rapid measurement of blood-flow rate in critical conditions.

Death and legacy

Doll passed away after long illness on 25 July 1991 in Montfort-l'Amaury, close to Paris. He is buried next to the grave of Francis Conrad Schlumberger in the private cemetery of the Schlumberger family mansion located in Normandy. He was survived by his ex-wife Annette Gruner Schlumberger (1905-1993), his daughters - Mrs. Frank Davidson, Mrs. Jean Lebel, and Mrs. Arnaud de Vitry - 10 grandchildren and 23 great grandchildren (FIG. 13).

Doll had a very prolific 50-year career during which he achieved the authorship of more than 150 patents and over 50 publications. He engineered and manufactured groundbreaking geophysical instruments, calculated and tested new interpretation models and methods in electrical engineering applied to geophysical research; and, trained two generations of internationally affirmed researchers and practitioner (FIG. 14).

Doll was a member of SPE and its predecessor organizations for 50 years. He was an SPE Distinguished Member and received the 1970 Anthony F. Lucas Gold Medal for his contributions to the industry. He was also a philanthropist and benefactor of many cultural organizations.

Figures

Honors

  • Lucas Gold Medal[9] of the American Institute of Mining, Metallurgical and Petroleum Engineers.
  • Gold Medal Award of the Society of Professional Well Log Analysts [10]
  • Certificate of Appreciation from the US government (contribution to the development of a model of landmine detector during the WWII)
  • Officier de la Légion d’Honneur[11] from the French government

Patents

Selection of Patents authored by Henri-Georges Doll between 1936 and 1978
ID Title Assignee Filing Date Publication Date
US-2582314-A Electromagnetic well logging system Schlumberger Well Surv Corp 6/15/1949 1/15/1952
US-2476137-A Method of positioning apparatus in boreholes Schlumberger Well Surv Corp 5/16/1942 7/12/1949
US-2747401-A Methods and apparatus for determining hydraulic characteristics of formations traversed by a borehole Schlumberger Well Surv Corp 5/13/1952 5/29/1956
US-2427950-A Method and apparatus for determining the dip of strata traversed by a borehole Schlumberger Well Surv Corp 1/1/1943 9/23/1947
US-2712629-A Electrical logging of earth formations traversed by a bore hole Schlumberger Well Surv Corp 3/7/1951 7/5/1955
US-2712630-A Methods and apparatus for electrical logging of wells Schlumberger Well Surv Corp 11/20/1951 7/5/1955
US-3060373-A Apparatus for investigating earth formations Schlumberger Well Surv Corp 6/16/1959 10/23/1962
US-2497042-A Electrooptical function synthesizer Electro Mechanical Res Inc 10/19/1943 2/7/1950
US-3166709-A Method and apparatus for providing improved vertical resolution in induction well logging including electrical storage and delay means Schlumberger Well Surv Corp 4/17/1959 1/19/1965
US-2669690-A Resistivity method for obtaining indications of permeable for mations traversed by boreholes Schlumberger Well Surv Corp 10/18/1949 2/16/1954
US-2728047-A Methods and apparatus for logging spontaneous potentials in wells Schlumberger Well Surv Corp 6/13/1952 12/20/1955
US-2712627-A Electrical resistivity well logging method and apparatus Schlumberger Well Surv Corp 5/12/1950 7/5/1955
US-2433746-A Method and apparatus for investigating earth formations traversed by boreholes Schlumberger Well Surv Corp 6/13/1942 12/30/1947
US-2814017-A Methods for logging the formations traversed by a borehole Schlumberger Well Surv Corp 5/26/1953 11/19/1957
US-2592125-A Method and apparatus for logging static spontaneous potentials in wells Schlumberger Well Surv Corp 11/18/1949 4/8/1952
US-2669688-A Resistivity apparatus for obtaining indications of permeable formations traversed byboreholes Schlumberger Well Surv Corp 5/29/1953 2/16/1954
US-2788483-A Phase rejection networks Schlumberger Well Surv Corp 5/24/1947 4/9/1957
US-2582315-A Differential coil system for induction logging Schlumberger Well Surv Corp 9/3/1949 1/15/1952
US-3132298-A Methods and apparatus for investigating earth boreholes by means of electrodes constructed to contact the borehole walls Schlumberger Well Surv Corp 6/16/1959 5/5/1964
US-2669689-A Method and apparatus for determining earth for mation factors Schlumberger Well Surv Corp 4/13/1945 2/16/1954
US-2736967-A Induction caliper Schlumberger Well Surv Corp 2/9/1952 3/6/1956
US-2749503-A Electrical logging in non-conductive drilling liquids Schlumberger Well Surv Corp 11/28/1951 6/5/1956
US-2712628-A Electrical logging apparatus Schlumberger Well Surv Corp 2/19/1951 7/5/1955
US-2363234-A Delayed action fuse Schlumberger Well Surv Corp 10/6/1941 11/21/1944
US-2476136-A Method and apparatus for locating predetermined levels in boreholes Schlumberger Well Surv Corp 4/19/1940 7/12/1949
US-2463362-A Automatic control system for vehicles Doll Henri-Georges 2/7/1947 3/1/1949
US-3013102-A Electrostatic shields Electro Mechanical Res Inc 5/24/1945 12/12/1961
US-2826736-A Methods and apparatus for exploring boreholes Schlumberger Well Surv Corp 4/21/1955 3/11/1958
CA-475931-A Methods and apparatus for investigating earth formations Schlumberger Well Surveying Corporation, Doll Henri-Georges 8/7/1951
US-2725523-A Multiple coil apparatus for induction well logging Schlumberger Well Surv Corp 6/6/1952 11/29/1955
US-2786178-A Apparatus for electrical well logging Schlumberger Well Surv Corp 12/19/1951 3/19/1957
US-2457214-A Recording device Schlumberger Well Surv Corp 7/21/1942 12/28/1948
US-2550004-A Method of establishing markers in boreholes Schlumberger Well Surv Corp 12/22/1943 4/24/1951
US-2807777-A Coil assembly for geophysical prospecting Doll Henri-Georges 5/24/1945 9/24/1957
US-3012190-A Multiple frequency alternating current network Electro Mechanical Res Inc 3/6/1946 12/5/1961
US-3493849-A Methods and apparatus for investigating earth formations wherein the vertical resolution of a first exploring means is altered to approximate the vertical resolution of a second exploring means Schlumberger Technology Corp 7/31/1968 2/3/1970
US-2704347-A Electrodes for electrical well logging Schlumberger Well Surv Corp 12/6/1951 3/15/1955
US-2761103-A Induction well logging apparatus Schlumberger Well Surv Corp 8/5/1952 8/28/1956
US-2747402-A Differential pressure well logging Schlumberger Well Surv Corp 9/27/1951 5/29/1956
US-2753520-A Methods and systems for maintaining alternating current networks in a reference condition Schlumberger Well Surv Corp 3/23/1946 7/3/1956
US-2316942-A Apparatus for measuring temperatures in boreholes Schlumberger Well Surv Corp 5/6/1941 4/20/1943
US-2475353-A Well surveying apparatus Schlumberger Well Surv Corp 10/8/1947 7/5/1949
US-2713146-A Spontaneous potential well logging method and apparatus Schlumberger Well Surv Corp 6/3/1953 7/12/1955
US-2829825-A Automatic computing apparatus Schlumberger Well Surv Corp 7/1/1952 4/8/1958
US-2463252-A Frequency stabilization of alternating current networks Schlumberger Well Surv Corp 3/8/1946 3/1/1949
US-3012189-A Capacitive detector Electro Mechanical Res Inc 6/5/1945 12/5/1961
US-2550005-A Well logging method and apparatus utilizing periodically variable spontaneous potentials Schlumberger Well Surv Corp 4/22/1948 4/24/1951
US-2395617-A Method for determining the oil content of subterranean formations Schlumberger Well Surv Corp 3/24/1942 2/26/1946
US-3072844-A Electrical measuring systems Schlumberger Well Surv Corp 10/14/1958 1/8/1963
US-2813249-A Well logging apparatus Schlumberger Well Surv Corp 6/10/1953 11/12/1957
US-2859915-A Function generator of two independent variables Schlumberger Well Surv Corp 6/2/1953 11/11/1958
US-2859916-A Automatic computing apparatus Schlumberger Well Surv Corp 6/2/1953 11/11/1958
US-2475354-A Well logging equipment Schlumberger Well Surv Corp 10/8/1947 7/5/1949
US-2554174-A Well logging method and apparatus Schlumberger Well Surv Corp 10/8/1947 5/22/1951
US-2915242-A Automatic computing apparatus Schlumberger Well Surv Corp 6/2/1953 12/1/1959
US-2712626-A Selective spontaneous potential well logging method and apparatus Schlumberger Well Surv Corp 11/18/1948 7/5/1955
US-2338029-A Well surveying apparatus Schlumberger Well Surv Corp 1/21/1941 12/28/1943
US-2712632-A Electrical well logging method and apparatus Schlumberger Well Surv Corp 6/3/1953 7/5/1955
DE-1020418-B Device for examining the strata drilled by a borehole Schlumberger Overseas 3/7/1952 12/5/1957
US-2707266-A Systems for investigating spontaneous potentials in wells Schlumberger Well Surv Corp 9/9/1953 4/26/1955
US-2884195-A Electro-optical function generator Schlumberger Well Surv Corp 9/20/1956 4/28/1959
AU-41554-A Apparatus for logging the formations traversed bya borehole Schlumberger Well Surveying Corporation 5/21/1954 11/25/1954
DE-906834-C Methods and devices for the investigation of the layers of benches penetrated by a borehole Schlumberger Overseas 5/6/1951 3/18/1954
DE-1025654-B Computing device with photoelectric devices Schlumberger Well Surv Corp 6/14/1954 3/6/1958
US-2983874-A Phase responsive alternating current networks Schlumberger Well Surv Corp 12/20/1955 5/9/1961
GB-678901-A Improvements in or relating to electromagnetic well logging systems Schlumberger Well Surv Corp 5/25/1951 9/10/1952
CA-624715-A Phase selective alternating current networks Doll Henri-Georges, Schlumberger Limited 8/1/1961
DE-1243291-B Device for obtaining information about the electrical resistance of the earth in a relatively thin zone behind the side wall of a borehole drilled in the earth Schlumberger Well Surv Corp 6/15/1960 6/29/1967
DE-898785-C Method and device for determining the soil layers penetrated by a borehole Schlumberger Prospection 2/16/1939 12/3/1953
CA-563136-A Automatic computing apparatus Schlumberger Limited, Doll Henri-Georges 9/9/1958
CA-569146-A Selective spontaneous potential well logging method and apparatus Doll Henri-Georges, Schlumberger Limited 1/20/1959
CA-585327-A Multiple coil apparatus for electrical induction well logging Doll Henri-Georges, Schlumberger Limited 10/20/1959
DE-921862-C Method and apparatus for determining the formations in a borehole Schlumberger Well Surv Corp 7/17/1952 12/30/1954
CA-564085-A Induction well logging apparatus Doll Henri-Georges, Schlumberger Limited 9/30/1958
CA-683276-A Apparatus for investigating earth formations Doll Henri-Georges, Schlumberger Well Surveying Corporation 3/31/1964
CA-574809-A Methods for logging the formations traversed by a borehole Doll Henri-Georges, Schlumberger Limited 4/28/1959
CA-550070-A Resistivity method and apparatus for obtaining indications of permeable formations traversed by a bore hole Doll Henri-Georges, Schlumberger Limited 12/10/1957
CA-699394-A Methods and apparatus for investigating earth formations Schlumberger Well Surveying Corporation, Doll Henri-Georges 12/8/1964
CA-641529-A Phase selective networks Schlumberger Limited, Doll Henri-Georges 5/22/1962
CA-477707-A Methods of fixing locations in bore holes Schlumberger Well Surveying Corporation, Doll Henri-Georges 10/9/1951
CA-532838-A Method and apparatus for investigating earth formations Doll Henri-Georges, Schlumberger Well Surveying Corporation 11/6/1956
CA-558350-A Electrical logging of earth formations traversed by a bore hole Doll Henri-Georges, Schlumberger Limited 6/3/1958
CA-548478-A Electrical logging apparatus Schlumberger, Doll Henri-Georges 11/5/1957
AU-206525-B2 Apparatus for logging the formations traversed bya borehole Schlumberger Well Surveying Corporation 5/21/1954 11/25/1954
CA-549410-A Methods and apparatus for electrical logging of wells Doll Henri-Georges, Schlumberger Limited 11/26/1957
US-2230999-A Method of indicating spontaneous potentials in shallow wells Schlumberger Well Surv Corp 2/25/1939 2/11/1941
US-2842961-A Flow measurement in wells Schlumberger Well Surv Corp 9/16/1954 7/15/1958
US-2317259-A Device for determining the strata traversed by drill holes Schlumberger Well Surv Corp 2/15/1938 4/20/1943
US-2238015-A Resistance thermometer and method of manufacturing the same Schlumberger Well Surv Corp 12/27/1937 4/8/1941
US-2249751-A Arrangement for measuring temperatures at a distance, particularly in boreholes Schlumberger Well Surv Corp 12/27/1937 7/22/1941
US-2258700-A Recording apparatus Schlumberger Well Surv Corp 5/12/1937 10/14/1941
US-2176169-A Method and arrangement for determining the direction and the value of the dip of beds cut by a bore hole Schlumberger Prospection 7/23/1936 10/17/1939
US-4036215-A Apparatus and method for eliminating perturbations of a kinetic origin in the blood flow waveform Doll Research, Inc. 2/6/1975 7/19/1977
DE-2344211-A1 BLOOD FLOW MEASUREMENT ARRANGEMENT AND METHOD OF USING THIS ARRANGEMENT Doll Research 9/1/1973 4/25/1974
GB-691344-A Improvements in or relating to phase selective networks Schlumberger Overseas 7/4/1951 5/13/1953
US-3659591-A Electromagnetic flowmeter Doll Research 8/24/1970 5/2/1972
US-3466533-A Induction logging apparatus with reduced diameter auxiliary coil means Schlumberger Technology Corp 5/1/1967 9/9/1969
DE-898642-C Method and device for the investigation of boreholes by electromagnetic means Schlumberger Overseas 7/18/1951 12/3/1953
DE-681396-C Method and device for determining the direction of the strike, the direction of the fall and, if necessary, the angle of fall of the soil layers penetrated by a borehole Schlumberger Prospection 3/9/1937 9/21/1939
DE-962377-C Method of recording a diagram on a moving strip of photosensitive material by means of several beams of light Prospection Electr Prodedes Sc 4/20/1937 4/18/1957
CA-446576-A Electro-optical function synthesizer Georges Doll Henri 2/10/1948
DE-934003-C Vorrichtung zur Untersuchung der Umgebung von eine leitende Fluessigkeit enthaltenden Bohrloechern mittels Induktionsstroemen Schlumberger Well Surv Corp 7/31/1953 10/6/1955
DE-912727-C Verfahren zum Abtrennen einer Komponente von gegebener Phasenbeziehung aus einem Wechselstromsignal, insbesondere zur Feststellung von Metallkoerpern Schlumberger Overseas 8/21/1951 6/3/1954
CA-552061-A Methode et appareil de sondage electromagnetique de puits Schlumberger Limited, Doll Henri-Georges 1/21/1958
DE-722455-C Verfahren zur gleichzeitigen Messung zweier oder mehrerer Groessen im Innern eines Bohrloches Schlumberger Prospection 12/15/1939 7/10/1942
CA-568475-A Computateur automatique Doll Henri-Georges, Schlumberger Limited 1/6/1959
DE-722456-C Verfahren insbesondere zur Untersuchung der durch ein Bohrloch durchschlagenen Schichten Schlumberger Prospection 12/16/1939 7/11/1942
CA-582333-A Sondage de puits par pression differentielle Schlumberger Limited, Doll Henri-Georges 9/1/1959
DE-851935-C Verfahren und Vorrichtung zur Untersuchung der von einem Bohrloch durchteuften Gesteinsschichten Schlumberger Prospection 9/19/1950 10/9/1952
CA-471839-A Systemes de commande automatique pour vehicules Doll Henri-Georges 3/6/1951
CA-566304-A Computateur automatique Schlumberger Limited, Doll Henri-Georges 11/18/1958
CA-537082-A Methode et appareil d'exploitation spontanee et statique de puits latents Schlumberger Well Surveying Corporation, Doll Henri-Georges 2/12/1957
CA-546410-A Methode et appareil d'exploitation de puits de resistivite electrique Doll Henri-Georges, Schlumberger Limited 9/17/1957
CA-584473-A Appareil automatique a calculer Doll Henri-Georges, Schlumberger Limited 10/6/1959
CA-566305-A Computateur automatique Schlumberger Limited, Doll Henri-Georges 11/18/1958
DE-945172-C Bohrschachtuntersuchungsgeraet zur Messung des elektrischen Widerstandes von Erdformationen Schlumberger Overseas 1/29/1952 7/5/1956
DE-1181339-B Vorrichtung zur Ermittlung des elektrischen Widerstandes von Erdformationen, die ein Bohrloch umgeben Schlumberger Well Surv Corp 8/4/1952 11/12/1964
DK-138578-B Electromagnetic flow meter. Doll Research 8/24/1971 10/2/1978

See also

References

Allaud, Louis A., and Maurice H. Martin. 1977. Schlumberger. The history of a technique. New York: John Wiley and Sons.

Anonymous. 1992. “Henri-Georges Doll”. The Leading Edge 11, no 8: 27-28.

Auletta, Ken. 1984. The Art of Corporate Success. New York: New York, USA: Putnam.

Christelle, Robin. 2003. “Conrad et Marcel Schlumberger: une aventure industrielle originale.” Bulletin de la Sabix 34: 5-14.

Doll, Henry-Georges. 1949. “Introduction to Induction Logging and Application to Logging of Wells Drilled with Oil Base Mud.” Journal of Petroleum Technology 1: 148–162.

Doll, Henry-Georges. 1953. “Two Decades of Electrical Logging”. Journal of Petroleum Technology, September 1953, 33-41.

Gerali, Francesco. 2020. 47th ICOHTEC Meeting - 1st Digital ICOHTEC, (Eindhoven, The Netherlands), July 15-17. The Search for Dark Spots. Early development of the Carottage Électrique (1910-1930). Oral Presentation.

Schlumberger. 2007. Oilfield Services Marketing Communications. 80 Years of Innovation. Corporate Publication: Sugar Land, Texas, USA.

Schlumberger, Gruner Anne. 1982. The Schlumberger Adventure. Arco Publishing: New York, USA.

Schlumberger, Jean, Schlumberger, Dominique. 1949. Conrad Schlumberger. Privately published.

Schlumberger, Francis Conrad, Schlumberger, Marcell. 1929. “Communication sur le carottage Electrique”. Compte Rendu Deuxieme Congress International de Forages, Paris, Septembre 1929. Conference Paper.

Schlumberger, Conrad, Schlumberger, Henri Émile Marcell. 1929. “Electrical Logs and Correlations in Drill Holes”. Mining Metallurgy 10: 515-518.

Further Reading