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U.S. Department of Energy
Office of Scientific and Technical Information

Geophysical methods for investigating boreholes; Geofizicheskie metody issledovaniya skvazhin

Book ·
OSTI ID:4423828
The equipment and arrangement required to make electrical resistivity measurements on various strata during drilling operations are described. Surveying with single, three- and seven-electrode units is described. Considerable background material on resistivity measurements is presented. Induction methods are also described. The radiometric methods include gamma surveying, where the natural radioactive content of strata materials (uranium and thorium generally) is measured by gamma counting. Clay minerals show a high count, while sand and dolomite minerals give low gamma counts. In gamma-gamma methods of surveying boreholes the amount of soft scattered gamma radiation depends mainly on the density of the stratum, and is inversely proportional to the heawy metal content. This method is most useful in determining the density of a stratum. Neutron survey methods are useful in detecting high hydrogen content of a straturn (one containing gas or oil) or in determining the composition of a stratum from the induced activ1ty. The characteristics of these detectors are described in detail. The character1stics of acoustic and magnetic survey methods are described. Methods of analyzing the dr1lling mud for hydrocarbon gases are presented. Ternperature measurements in the borehole, and methods of measuring the curvature of the borehole are presented. The use of computers in interpreting and using survey data is discussed. (SJR)
Research Organization:
Originating Research Org. not identified
NSA Number:
NSA-29-002643
OSTI ID:
4423828
Country of Publication:
Country unknown/Code not available
Language:
English