Premium
FAST AUTOMATIC PROCESSING OF RESISTIVITY SOUNDINGS *
Author(s) -
BICHARA M.,
LAKSHMANAN J.
Publication year - 1976
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1976.tb00932.x
Subject(s) - electrical resistivity and conductivity , depth sounding , filter (signal processing) , vertical electrical sounding , point (geometry) , distribution (mathematics) , mineralogy , geology , field (mathematics) , algorithm , geophysics , mathematical analysis , computer science , mathematics , geometry , geotechnical engineering , electrical engineering , engineering , groundwater , oceanography , aquifer , pure mathematics , computer vision
A bstract The difficulty to use master curves as well as classical techniques for the determination of layer distribution ( e i , ρ i ) from a resistivity sounding arises when the presumed number of layers exceeds five or six. The principle of the method proposed here is based on the identification of the resistivity transform. This principle was recently underlined by many authors. The resistivity transform can be easily derived from the experimental data by the application of Ghosh's linear filter, and another method for deriving the filter coefficientes is suggested. For a given theoretical resistivity transform corresponding to a given distribution of layers (thicknesses and resistivities) various criteria that measure the difference between this theoretical resistivity transform and an experimental one derived by the application of Ghosh's filter are given. A discussion of these criteria from a physical as well as a mathematical point of view follows. The proposed method is then exposed; it is based on a gradient method. The type of gradient method used is defined and justified physically as well as with numerical examples of identified master curves. The practical use for the method and experimental confrontation of identified field curves with drill holes are given. The cost as well as memory occupation and time of execution of the program on CDC 7600 computer is estimated.