Numerical study of an alternative to a deuterium-tritium source in gas saturation logging based on the inelastic gamma spectrum.

In this study, we investigated the feasibility of using a D-Li7 neutron generator to replace a deuterium-tritium (D-T) neutron generator in gas saturation logging. The logging response and gas sensitivity of gas saturation logging based on the inelastic gamma spectrum were simulated with the Monte Carlo method, and the factors that influenced the gas sensitivity and inelastic gamma counts were analyzed based on the spatial response distribution. The results showed that the logging response based on the D-Li7 source was similar to that based on the D-T neutron generator after calibration, which validated the feasibility of this method. Using the D-Li7 neutron generator, the sensitivity of gas saturation was higher when the scattering cross section of formation was not high.