Simulation and verification of a slim X-ray density logging tool

Abstract

With advancements in oil and gas exploration, the design and measurement methods of X-ray density logging tools have gained significant attention as a new generation of controllable sources. Using an existing ultra-slim gamma tool as an example, this work shows how the tool could be re-designed by replacing the gamma source with an X-ray source. The key aspects of this study include: 1) Simulating the production of X-ray with different energies; 2) Studying the optimum spacing of X-ray logging tool by considering the factors of detection efficiency, density measurement sensitivity, and depth of investigation; 3) Performing X-ray density measurements using multivariable forward and inversion methods and comparing the results with gamma density logging. The findings reveal that by adjusting the spacing of near and far detectors to 110 mm and 290 mm respectively, the X-ray logging tool achieves performance comparable to or even surpassing it of the gamma tool. In comparison to gamma logging, X-ray logging demonstrates superior formation sensitivity, vertical resolution, and formation density measurement accuracy. Notably, in heavy mudcake condition, the X-ray logging tool enhances the Pe measurement accuracy by 47%. These investigations serve as valuable insights for the forward design of X-ray logging tools and formation density measurements.