Modeling analysis of environmental effects on accelerator porosity logging measurements

MNCP modeling of an accelerator porosity sonde tool was performed in an 8-inch borehole over the complete porosity range in order to investigate its epithermal neutron response to porosity and the most significant environmental variables that affect the porosity measurement, including tool standoff, temperature, and formation lithography. The results obtained in limestone, sandstone, and dolomite formations are compared to experiments. The variations with temperature and standoff are illustrated in the case of limestone formations