Litho-Density Tool Calibration

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Abstract
A second-generation density logging tool has been developed that uses a gamma-ray source and two Nal scintillator detectors for borehole measurement of electron density, pe, and a quantity Fpe that is related to the lithology of the formation. An active stabilization system controls the gains of the two detectors, which permits selective gamma-ray detection. Spectral analysis is performed in the near detector (two energy windows) and in the detector farther away from the source (three energy windows). This paper describes the results of laboratory measurements undertaken to define the basic tool response. The tool is shown to provide reliable measurements of formation density and lithology under a variety of environmental conditions.