Radiant energy – Geological testing or irradiation – Well testing apparatus and methods
Patent
1991-06-06
1992-06-09
Hannaher, Constantine
Radiant energy
Geological testing or irradiation
Well testing apparatus and methods
250262, G01V 506
Patent
active
051209551
ABSTRACT:
A method and apparatus for determining the presence of at least one naturally radioactive element in an earth formation surrounding a borehole, wherein, for each depth in the borehole, a spectrum is made of the gamma rays detected in several energy channels, and expressed as U=S Y, where "Y" is the elemental yields and "S" is a composite spectra matrix made of individual standard spectra characteristic of a given borehole environment; yields Y are then calculated. One thus determines a borehole correction factor from the general relationship between the borehole parameters, the standard spectra and the measured spectra. Finally, the yields are corrected for borehole effects by applying the correction factor.
The correction factor is energy independent, at least for energies above a given threshold, and is also independent from the radioactive elements.
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Bouchard John H.
Garrana Henry N.
Hannaher Constantine
Schlumberger Technology Corporation
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