Halliburton Company

John G Kampfer

Allen Nunley

Lucian A Ingram

For use in a nuclear well logging tool, detector pulse simulator circuits in the preferred and illustrated embodiments are set forth. The simulator circuit is adapted to be placed in a sonde for connection with a well logging tool to provide simulated detector pulses. It is selectively switched on to the output a calibrated pulse sequence function through a number of different levels. It incorporates a circuit means forming pulses limited in amplitude by an envelope yielding pulses of differing amplitude in progression. The circuit is stepped repetitively through its range of operation, for example, from a minimum voltage peak to some specified maximum and then recycles.

Detector pulse forming system for nuclear well logging tools

The present invention presents a method and apparatus for stabilizing signals in radioactive well logging tools including providing in the tool a main scintillating crystal and photomultiplier tube for detecting radiation induced in the borehole by a source of radiation, and a reference crystal, including a source of mono-energetic radiation, for producing continuous reference signals of a predetermined energy level. The reference signals are monitored and the spectrum is stabilized to correct for drift of the data signals introduced by the photomultiplier tube and the data transmission system. The preferred mono-energetic reference signals are selected to appear in the energy spectrum at a level which minimizes error. An electronic circuit at the surface provides a correction signal for adjusting the gain of a data signal amplifier responsive to changes in the reference signal, thereby correcting for drift in the data signal.

Method and apparatus for stabilizing signals in radioactive well logging

A method and apparatus for converting a single function, i.e., hydrocarbon detection, well logging tool to a dual function tool, i.e., the detection of naturally occurring gamma rays, by making the amplitude reference pulses necessary for single function operation related in rate to the second function. A minimum constant rate of amplitude reference pulses are provided to ensure the operability of the single function tool in the absence of the second function and an adjustment is thereafter made to remove the effects of this minimum rate of reference pulses.

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Houston, TX, United States of America

John G Kampfer