The Medal Award of the Society of Exploration Geophysicists was established to honor individuals who have either made a distinct technical contribution such as an invention or an outstanding paper, or have gained special recognition by fellow workers.
     Charles B. Vogel is one of the three 1971 Medalists being recognized for their contributions in the field of velocity logging.
     In the late 1940s when useful interval velocity measurements began to be available the major interest came from exploration seismologists. Regional velocity maps were made and the effects of horizontal velocity gradients could be corrected in greater detail. In the 1950s synthetic seismograms became possible and improved understanding of reflection coefficients and geologic correlations was acquired. These detailed velocity data permitted improved geophysical interpretations.
     By 1954 the velocity log was recognized as a porosity tool by the petrophysicists and it has now firmly established itself as a standard log. Relative amplitude measurements from the log have been useful in detecting poor casing cement bonds and this has contributed to better and safer cementing practices. It was the first log used to anticipate over-pressured zones in advance of the drill bit in the Gulf Coast by recording and noting changes in the velocity gradient with depth. This information led to
     successful exploitation of many over-pressured reservoirs. By observing relative amplitudes of the various arrivals, it has been possible to qualitatively locate fractured zones in a number of hard and carbonate formations.
     Recently more attention has been given to the detailed seismic exploration important to production geology and production engineering, and the velocity log holds a position of central importance.
     Charles B. Vogel was graduated from the University of Western Ontario in 1940. He did graduate work at the University of Houston and Wayne University and was an instructor at the Assumption College in the year 1942-43. He was employed as a merchant marine radio operator during 1944 and 1945. In 1945 he joined the staff of the Exploration and Production Research Laboratory of Shell Oil Company where he started working in the field of velocity logging. He is the inventor of basic patents in the field 2,651,027 filed October 1, 1949; 2,708,485 filed April 29, 1952; and 2,915,738 filed January 22, 1957. At the 22nd Annual International SEG Meeting in Los Angeles, on March 26, 1952, he presented "A Seismic Velocity Logging Method," one of the two
     landmark papers in this field. The paper was published subsequently in Geophysics, July 1952.
     Many individuals have made significant and useful contributions to the field of velocity logging. Mr. Vogel and his co-medalists are singled out for recognition for their early publications and patents that teach the art which anticipated the present direction of development of velocity equipment and techniques. In his early paper and patents Mr. Vogel taught the useful methods of bringing the amplitude-traveltime signals to the surface where the character and amplitudes could be studied and interpreted.
     He also taught the method of "up-and-down" averaging, which eliminates the errors produced by changing borehole diameter.
     Noyes D. Smith, Jr.