Radiant energy – Geological testing or irradiation – Well testing apparatus and methods
Patent
1992-01-09
1993-08-10
Fields, Carolyn E.
Radiant energy
Geological testing or irradiation
Well testing apparatus and methods
250266, 250270, G01V 510, G01V 514
Patent
active
052351858
ABSTRACT:
A tool which contains a pulsed accelerator neutron source and means for making timing measurements of the thermal neutron response in a localized portion of the environment immediately surrounding the borehole. Formation sigma is determined by parameterizing the detected thermal neutron decay curve, preferably with a diffusion model similar to that known in the art for determining formation sigma on the basis of gamma ray time distributions. In a more comprehensive embodiment of the present invention, which includes a gamma detector in the tool, formation sigma can be measured in parallel using both gamma ray and thermal neutron decay characteristics. Deviations between the neutron and gamma-based signals that occur as the tool traverses the borehole, provide useful indications of local effects immediately surrounding the borehole.
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Albats Paul
Hertzog Russell C.
Mahdavi Mehrzad
Fields Carolyn E.
Pojunas Leonard W.
Ristas L. James
Schlumberger Technology Corporation
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