METHOD OF NUCLEAR MAGNETIC VOLTAGE AND A DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2018 - IPC G01V3/14 

FIELD: mining.

SUBSTANCE: using for well logging using nuclear magnetic resonance (NMR). Summary of the Invention is moving along the well of the logging tool, in which two basic coaxial permanent magnets oriented with the same poles to each other create a constant magnetic field polarized in the perpendicular direction to the longitudinal axis of the magnets in the remote investigated region in the rock stratum, in the same region a radio frequency pulse train is created at the frequency of nuclear magnetic resonance by the radio frequency receiving and transmitting coil, forming an alternating magnetic field polarized perpendicular to the constant magnetic field, using the same coils, in the intervals between radio frequency pulses, the signals of the spin NMR echo are detected, the amplitude of the echo signals is calculated from the time spectra of the transverse and longitudinal relaxation times and the characteristics of the underground formations are calculated, in order to ensure that it is possible to exclude the effect on the amplitude of the echo signals of the temperature dependence of the magnetic field produced by the main permanent magnets, directly in the course of the logging by changing the current in two bias coils, an additional magnetic field is created so that the values of the resulting magnetic field in the investigated zone remain constant, at which the conditions for obtaining the maximum of the NMR signal and the depth of investigation are observed.

EFFECT: ensuring the possibility of compensating the temperature dependence of the residual induction of permanent magnets without degrading the depth profile of the study.

2 cl, 3 dwg