Well logging neutron generator control system
AssigneeHalliburton Company
InventorsHarold E. Peelman, James R. Bridges
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Abstract
A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a neutron output control system. The control system monitors the target beam current and compares a function of this current with a reference voltage level to develop a control signal. The control signal is used in a series regulator to control the replenisher current of the neutron generator tube.
Claims8
A control system for controlling the output of a sealed off generator tube having a target material, an ion source, and a replenisher pressure regulator, comprising:
- means for monitoring the average target current of said tube and for developing a voltage signal representative thereof;
- means for comparing a function of said average target current representative signal with a reference voltage signal and for developing a control voltage signal representative of the comparison of said signals, said comparing means including an operational amplifier and means for summing said target current representative signal and a voltage signal representative of the replenisher current of said tube to form a summation signal and for comparing said summation signal and said reference voltage signal in said operational amplifier to provide an output control signal;
- and
- control means, responsive to said control signal, for controlling current flow to the replenisher of said tube as a function thereof.
A well logging system for conducting pulsed neutron well logging operations, comprising:
- a fluid tight hollow body member sized and adapted for passage through a well borehole and housing therein;
- a radiation detector for detecting radiations emanating from earth formations in the vicinity of the well borehole in response to neutron irriadiation thereof;
- and
- a sealed off neutron generator tube having a target material, an ion source, and a replenisher pressure regulator and a control system therefor, comprising:
- means for monitoring the average target current of said tube and for developing a voltage signal representative thereof;
- means for comparing a function of said average target current representative signal with a reference voltage signal and for developing a control voltage signal representative of the comparison of said signals, said comparing means including an operational amplifier and means for summing said target current representative signal and a voltage signal representative of the replenisher current of said tube to form a summation signal and for comparing said summation signal and said reference voltage signal in said operational amplifier to provide an output control signal;
- and
- control means, responsive to said control signal, for controlling current flow to the replenisher of said tube as a function thereof.
Dependencies are inferred from the claim text.