METHOD AND APPARATUS FOR DETERMINING POROSITY AND SATURATION OF FORMATIONS BASED SIMULTANEOUSLY ON THERMAL AND EPITHERMAL NEUTRONS Russian patent published in 2012 - IPC G01V5/04 

FIELD: physics.

SUBSTANCE: formation is exposed to pulsed neutron sources; radiation is detected in the well bore at several points and the corresponding density and saturation values are determined, wherein the analysed rock is exposed to fast neutrons while periodically switching the pulse frequency from high (5-13 kHz) to low (20-2000 Hz) and back, wherein during periods when the emitter is operating at high pulse frequency, field density of epithermal and thermal neutrons is simultaneously measured at one or more points in space, and during periods when the emitter is operating at low pulse frequency, field density of thermal neutrons is measured at one or more points in space, wherein field density of epithermal and thermal neutrons is measured at radiation pulse recurrence intervals at different time delay values at the end of the radiation pulse of the fast neutrons.

EFFECT: high accuracy and reliability of obtained investigation results.

2 cl, 5 dwg