Measuring neutron parameters of rocks from pulsed neutron logs

Application of well logging pulsed neutron sources (neutron generators) allows one to study the time-spatial characteristics of neutron fields in the 'well- formation' system. From measurements of these characteristics one can determine neutron parameters of rocks: macroscopic neutron absorption (Σa) and scattering (Σs) cross-sections in rocks. These parameters depend on the componential (elemental) composition of rocks. An algorithm is proposed for measuring neutron parameters of rocks which takes into account a complicated geometry of downhole measurements and mutual effects of estimated parameters on measured functionals. From the results of physical and mathematical modeling studied is the dependence of measured functionals on neutron parameters. A logging tool destined for measurement of neutron parameters, methodical and metrological support to these measurements have been devised. (author)