Method and apparatus for determining neutron characteristics of borehole fluids

摘要

A source of high energy neutrons and a detector responsive to the thermal neutron population decay rate are utilized in a well logging instrument. The instrument is positioned within a borehole and at least a portion of the fluids within the borehole are irradiated with high energy neutrons. The thermal neutrons emanating from the irradiated fluids are detected and measured. The thermal neutron counts are converted into a time base measurement which is further converted into a measurement of the thermal neutron capture cross-section for the irradiated fluids.