Well bore gamma-ray spectrum equalization

Claim 1

A METHOD OF EMPHASIZING THE HIGH-ENERGY PORTION OF A GAMMA-RAY SPECTRUM WITHOUT SUBSTANTIAL INCREASE IN MEASURING TIME, WHEN ELECTRICAL PULSES REPRESENTING GAMMA RAYS ARE GENERATED IN A WELL BORE, TRANSMITTED OVER A LOGGING CABLE HAVING LIMITED INFORMATION TRANSMISSION CHARACTERISTICS, AND RECORDED ON A MULTICHANNEL PULSEHEIGHT ANALYZER AT THE EARTH''S SURFACE, WHICH COMPRISES (A) GENERATING IN SAID WELL BORE A PLURALITY OF ELECTRICAL PULSES, EACH PULSE BEING PROPORTIONAL IN HEIGHT TO THE ENERGY OF A GAMMA RAY DETECTED IN THE WELL BORE, (B) IN EACH SPECTRUM TO BE RECORDED, SELECTING AT RANDOM A FIRST ONE OF SAID PLURALITY OF ELECTRICAL PULSES FOR TRANSMISSION TO THE PULSE-HEIGHT ANALYZER AT THE EARTH''S SURFACE, SAID FIRST PULSE HAVING AT LEAST A PREDETERMINED MINIMUM AMPLITUDE, (C) REJECTING ALL SUCCEEDING ELECTRICAL PULSES FOR A KNOWN TIME PERIOD FOLLOWING SELECTION OF SAID PULSE, SAID TIME PERIOD BEING SUFFICIENT TO PERMIT SAID FIRST PULSE TO BE TRANSMITTED WITH MINIMUM DISTORTION, (D) REPETITIVELY SELECTING AT RANDOM ANOTHER OF SAID ELECTRICAL PULSES AFTER THE END OF SAID TIME PERIOD, REJECTING SUCCEEDING ELECTRICAL PULSES DURING EACH OF SAID TIME PERIODS, THE NUMBER OF REPEITIONS BEING ADEQUATE TO ACCUMULATE A STATISTICALLY RELIABLE SAMPLE OF THE AMPLITUDES OF ALL OF SAID PULSES FOR PRODUCTION OF A PULSE-HEIGHT SPECTRUM, AND (E) DURING EACH REPETITIVE SELECTION AND TRANSMISSION OF ONE OF SAID PULSES, PROGRESSIVELY INCREASING THE MINIMUM AMPLITUDE OF THE SELECTED PULSE FOR TRANSMISSION TO THE MULTICHANNEL ANALYZER WHEREBY THE HIGHER ENERGY PULSES ARE EMPHASIZED IN THE RECORDED SPECTRUM.

Claim 2

A METHOD OF EMPHASIZING THE HIGH-ENERGY PORTION OF A GAMMA-RAY SPECTRUM WITHOUT SUBSTANTIAL INCREASE IN MEASURING TIME, WHEN ELECTRICAL PULSES REPRESENTING GAMMA RAYS ARE GENERATED IN A WELL BORE, TRANSMITTED OVER A LOGGING CABLE HAVING LIMITED INFORMATION TRANSMISSION CHARACTERISTICS, AND RECORDED ON A MULTICHANNEL PULSEHEIGHT ANALYZER AT THE EARTH''S SURFACE, WHICH COMPRISES (A) GENERATING IN SAID WELL BORE A PLURALITY OF ELECTRICAL PULSES, EACH PULSE BEING PROPORTIONAL IN HEIGHT TO THE ENERGY OF A GAMMA RAY DETECTED IN THE WELL BORE, (B) IN EACH SPECTRUM TO BE RECORDED, SELECTING AT RANDOM A FIRST ONE OF SAID PLURALITY OF ELECTRICAL PULSES FOR TRANSMISSION TO THE PULSE-HEIGHT ANALYZER AT THE EARTH''S SURFACE, SAID FIRST PULSE HAVING AT LEAST A PREDETERMINED MINIMUM AMPLITUDE, (C) REJECTING ALL SUCCEEDING ELECTRICAL PULSES FOR A KNOWN TIME PERIOD FOLLOWING SELECTION OF SAID PULSE, SAID TIME PERIOD BEING SUFFICIENT TO PERMIT SAID FIRST PULSE TO BE TRANSMITTED WITH MINIMUM DISTORTION, (D) REPETITIVELY SELECTING AT RANDOM ANOTHER OF SAID ELECTRICAL PULSES AFTER THE END OF SAID TIME PERIOD, REJECTING SUCCEEDING ELECTRICAL PULSES DURING EACH OF SAID TIME PERIODS, THE NUMBER OF REPEITIONS BEING ADEQUATE TO ACCUMULATE A STATISTICALLY RELIABLE SAMPLE OF THE AMPLITUDES OF ALL OF SAID PULSES FOR PRODUCTION OF A PULSE-HEIGHT SPECTRUM, AND (E) DURING EACH REPETITIVE SELECTION AND TRANSMISSION OF ONE OF SAID PULSES, PROGRESSIVELY INCREASING THE MINIMUM AMPLITUDE OF THE SELECTED PULSE FOR TRANSMISSION TO THE MULTICHANNEL ANALYZER WHEREBY THE HIGHER ENERGY PULSES ARE EMPHASIZED IN THE RECORDED SPECTRUM.