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Title: Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation

Abstract

The theory and methodology of the neutron-based technique for the determination of the formation temperature in geothermal fields are discussed. The feasibility of the method was demonstrated before start of the present development phase. The present work is intended to evaluate the response of the temperature probe in a simulated fracture porosity granite matrix at temperatures likely to be encountered in known geothermal reservoirs. An above ground borehole model has been designed and constructed. The effect of high ambient temperatures on the response of the neutron detectors in the probe mockup used in the measurements was investigated and used to correct the detector counts. An improved data analysis method has been developed to account properly for the effects of low porosity and high temperatures. Measurements, using the above ground borehole model, have shown that a linear correlation between the ratio of thermal counts from a Gd-filtered detector to counts from a bare detector and formation temperature is good at temperatures as high as 380/sup 0/F. The present results are consistent with earlier data obtained in high-porosity laboratory models at lower temperatures (T < 167/sup 0/F). Further measurements at high temperature at various porosities and formation neutron absorption cross sections wouldmore » be necessary for a more extensive comparison.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
5282226
Report Number(s):
LA-9159-MS
ON: DE82009074
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of document are illegible
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; GEOTHERMAL WELLS; NEUTRON LOGGING; RESERVOIR TEMPERATURE; WELL LOGGING; BOREHOLES; DATA ANALYSIS; GRANITES; POROSITY; CAVITIES; IGNEOUS ROCKS; PLUTONIC ROCKS; RADIOACTIVITY LOGGING; ROCKS; WELLS; Geothermal Legacy

Citation Formats

Ross, E W, Vagelatos, N, Dickerson, J M, and Nguyen, V. Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation. United States: N. p., 1982. Web. doi:10.2172/5282226.
Ross, E W, Vagelatos, N, Dickerson, J M, & Nguyen, V. Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation. United States. https://doi.org/10.2172/5282226
Ross, E W, Vagelatos, N, Dickerson, J M, and Nguyen, V. 1982. "Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation". United States. https://doi.org/10.2172/5282226. https://www.osti.gov/servlets/purl/5282226.
@article{osti_5282226,
title = {Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation},
author = {Ross, E W and Vagelatos, N and Dickerson, J M and Nguyen, V},
abstractNote = {The theory and methodology of the neutron-based technique for the determination of the formation temperature in geothermal fields are discussed. The feasibility of the method was demonstrated before start of the present development phase. The present work is intended to evaluate the response of the temperature probe in a simulated fracture porosity granite matrix at temperatures likely to be encountered in known geothermal reservoirs. An above ground borehole model has been designed and constructed. The effect of high ambient temperatures on the response of the neutron detectors in the probe mockup used in the measurements was investigated and used to correct the detector counts. An improved data analysis method has been developed to account properly for the effects of low porosity and high temperatures. Measurements, using the above ground borehole model, have shown that a linear correlation between the ratio of thermal counts from a Gd-filtered detector to counts from a bare detector and formation temperature is good at temperatures as high as 380/sup 0/F. The present results are consistent with earlier data obtained in high-porosity laboratory models at lower temperatures (T < 167/sup 0/F). Further measurements at high temperature at various porosities and formation neutron absorption cross sections would be necessary for a more extensive comparison.},
doi = {10.2172/5282226},
url = {https://www.osti.gov/biblio/5282226}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1982},
month = {Fri Jan 01 00:00:00 EST 1982}
}