Fig. 1. Simple intention of X-ray scattering in formation

Fig. 2. Diagram of model of the density logging instrument for MCNP calculation

Fig. 3. Depth of investigation of the X-ray source

Fig. 4. Comparison of the depth of investigation of two sources for short-spacing detector (a) and long-spacing detector (b)

Fig. 5. Relationship between the depth of investigation and contribution rate (a) X-ray source, (b) ¹³⁷Cs source

Fig. 6. Effect of mudcake on counting rate

Fig. 7. Contribution rate of mudcake and formation to detectors (a) 1.27 cm mudcake, (b) 2.54 cm mudcake

Fig. 8. Relationship between the thickness of mudcake and density deviation (a) 1.27 cm mudcake, (b) 2.54 cm mudcake