Abstract: [Background] It has become an inevitable trend to use controlled source instead of isotope neutron source in neutron porosity logging for petroleum exploration, and the availability of measurement results is determined by formation sensitivity, which is required to be of a certain standard. [Purpose] This study aims to improve the compatibility and measurement accuracy of the controlled source for neutron porosity logging. [Methods] First of all, the response equation of formational porosity sensitivity is derviated according to the theoretical formula of neutron porosity logging's response, then the Schlumberger Nuclear Parameter (SNUPAR) program is applied to analysis of its adaptability and factors affecting the sensitivity of neutron porosity logging. [Results] Computaional results show that the deceleration length of neutron is the main role to the change of sensitivity, and the deceleration length is affected by source type and its energy, porosity, lithology, and density. And the neutron energy and rock density are the main factors that affect the sensitivity change. [Conclusion] This study provides a theoretical basis for the further study of controlled source neutron porosity logging.

Key words: Neutron porosity logging, Controllable source, Formation sensitivity, Deceleration length