Title :
Use of GSO for inelastic gamma-ray spectroscopy measurements in the borehole
Author :
Roscoe, B.A. ; Grau, J.A. ; Manente, R.A. ; Melcher, C.L. ; Peterson, C.A. ; Schweitzer, J.S. ; Stoller, C.
Author_Institution :
Schlumberger-Doll Res., Ridgefield, CT, USA
Abstract :
A novel inelastic gamma-ray spectroscopy tool using GSO (gadolinium oxyorthosilicate) detectors has been optimized for oil saturation measurements in the borehole. The use of GSO detectors has made it possible to perform gamma-ray spectroscopy in a small diameter tool at elevated temperatures. The design was optimized by taking into account the properties of the GSO scintillator in addition to other physical processes that affect the statistics of the measurement. The ability to compensate the oil saturation measurement for varying borehole fluid has also been demonstrated. The large neutron cross section of the gadolinium in the scintillation crystal, its second decay constant, and the desired precision of the coil saturation measurement were found to have important consequences in the tool design.<>
Keywords :
gadolinium compounds; gamma-ray detection and measurement; gamma-ray spectrometers; geophysical equipment; scintillation counters; Gd/sub 2/SiO/sub 4/O:Ce; borehole; elevated temperatures; inelastic gamma-ray spectroscopy; neutron cross section; oil saturation measurements; scintillator; second decay constant; Energy resolution; Gamma ray detection; Gamma ray detectors; Gamma rays; Neutrons; Petroleum; Solid scintillation detectors; Spectroscopy; Time measurement; Wavelength measurement;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference, 1991., Conference Record of the 1991 IEEE
Conference_Location :
Santa Fe, NM, USA
Print_ISBN :
0-7803-0513-2
DOI :
10.1109/NSSMIC.1991.259092
