In the litho-density logging

formation density and lithology were acquired by calculating the total counts in certain energy window.Therefore

the division of the energy window directly affects the evaluation of density and lithology value.In the process of the energy window division

mud type affects the determination of the range of energy window.In this work

Monte Carlo simulation method was applied to study the range of energy window regarding to water mud and barite mud

respectively.The results show that the range of the energy window with barite mud is less than that of the water mud

and lithology identification will have greater error in the barite mud.It is important to analyze influencing factors and improve the measurement accuracy of the litho-density logging.