基于实际井下X射线源参数,利用数值模拟方法研究Cs137 源和X射线源密度测井在能谱、密度灵敏度和精度方面的差异;并对X射线源密度测井的能窗、屏蔽体和探测器等参数进行优化,提出一种四探测器密度探测系统方案.结果表明:X射线源密度测量能窗应选取0.12~0.35 MeV;仪器结构无需增加纵向屏蔽体;为了满足密度测井需求,近探测器源距应大于12.0 cm,远探测器源距应设置在29~55.5 cm;通过四探测器密度探测系统方案可以使X射线密度测井兼顾纵向分辨率、探测深度、密度灵敏度和精度等方面的优势,更加适合复杂储层评价;研究可以为X射线源密度测井仪器研发提供硬件参数指导.
This study evaluated the differences between Cs137 and X-ray density logging tools in terms of their energy spec-trum,density sensitivity and precision utilizing the Monte Carlo method,based on the parameters of the actual underground X-ray source.Subsequently,optimizations were performed on the energy window,shield thickness and detector-spacings of the X-ray density tool.Eventually,a novel four-detector density detection system was proposed.The investigation revealed that the optimal energy window for the X-ray density tool should range between 0.12 MeV and 0.35 MeV.The structure of the X-ray density tool doesn't require the addition of longitudinal tungsten shielding.To ensure density sensitivity and accuracy,it was suggested that the spacing between the near detectors should exceed 12.0 cm,while the spacing of the far detectors should be within the range of 29 cm to 55.5 cm.By adopting the four-detector detection system,the X-ray density tool was conferred ad-vantages such as high longitudinal resolution,sensitivity and accuracy concurrently,which is more suitable for complex reser-voir evaluation.Overall,this research offers valuable guidance for the design parameters of X-ray density logging tools.