METHOD AND DEVICE FOR PULSE NEUTRON LOGGING Russian patent published in 2005 - IPC

FIELD: geophysics; geology; atomic industry.

SUBSTANCE: device can be used nuclear-geophysical inspection wells. Medium to be tested inside well is irradiated with pulses of quick neutrons of source. Two-probe registration is performed during gaps between pulses at specified time intervals in ionizing radiations induced by tested medium. Instability in yield of neutrons in pulse is estimated and measurements are made. Time spectra for sets of quick neutron pulses inside fixed time window are formed for n groups taking mentioned instability into account. Spectrometric data is processed in real time scale for any sub-quantum of spectrometric data in well tool. Results of processing are used for finding technological characteristics of well tool and corrections are introduced as well dead time of registration system is taken into account. Then deep quantum of spectrometric data is formed and decrement of decay of thermal neutrons is determined in tested media. Device has neutron pulse oscillator placed inside housing, small and big probes scintillation detectors provided with photomultiplier tube and program controlled amplifiers, central processor unit connected with data receiving-transmitting unit by means of two-direction circuit. Central processor unit has structurized on-line storage. Inputs of photomultiplier tubes of small and big probes are connected with outputs of high voltage power supply. Input of high voltage power supply is connected with first output of high voltage power supply. Second and third inputs of high voltage power supply are connected with second input of program-controlled amplifiers of small and big probes. Amplifiers of big and small probes are connected with two-direction circuit. Output of central processor unit is connected with first input of neutron pulse oscillator which has second input connected with output of neutron pulse oscillator supply decoupling unit which is connected with data receiving-transmitting unit by two-direction line. Output of data receiving-transmitting unit is connected with input of high voltage power supply. Fourth output of power supply is connected with input of central processor unit. Input-output of neutron pulse oscillator supply decoupling unit is connected with upper and lower joints. Multichannel measurements can be conducted at higher frequencies of generation of quick neutrons; corrections caused by instability of technological parameters of equipment can be introduced.

EFFECT: improved efficiency of operation.

2 cl, 3 dwg