Comparison of calculated and measured responses of a dual-detector epithermal neutron porosity device

The development of an epithermal neutron porosity has been greatly aided by model calculations to supplement laboratory measurements of environmental effects. Accurate computational models of this device have been developed using discrete ordinates and Monte Carlo techniques. The ability of the models to predict individual detector counting rates is demonstrated for the case of the basic porosity response. The validity of the models is further established by comparison with laboratory measurements of the experimental tool response to formation porosity, formation matrix, borehole size, tool stand-off, and temperature. 3 refs