Simulation and Comparative Study of Interaction Between Ray and Medium in Borehole Based on FLUKA Software

In nuclear logging, Monte Carlo simulation method is widely employed across various stages from instrument development and design to data interpretation. While Monte Carlo N-Particle Transport Code (MCNP) has been the primary tool for research and problem-solving in this domain, its usage has long been constrained by licensing restrictions, posing challenges for researchers. Leveraging FLUktuierende KAskade (FLUKA)’s open-access policy, this study establishes nuclear logging benchmark simulations to evaluate FLUKA’s viability as an alternative to MCNP. Representative benchmark models encompassing gamma-ray transport, neutron transport, and gamma-neutron coupled transport processes were developed in both FLUKA and MCNP. Key logging data, including gamma energy spectra, formation density, and porosity, were obtained to assess FLUKA’s performance in low-energy radiation transport simulations. Results demonstrate that for low-energy gamma transport, the maximum relative error between FLUKA and MCNP in formation-scattered gamma-ray spectra is 5.37%, with density response errors below 3.75%. For low-energy neutron transport, porosity responses show agreement within 1%, while relative errors in neutron-induced gamma-ray spectra generally remain under 5%. This comparative analysis confirms FLUKA’s capability to replace MCNP for nuclear logging applications.