碳氧比能谱测井曲线的质量评价

Quality appreciation of carbon-oxygen ratio spectral logging curves.

碳氧比能谱测井曲线的质量不但取决于测井仪本身的性能及技术水平 ,还取决于井眼和地层中的元素丰度 ,以及测井环境、测速、采样间隔等因素的影响。本文采用 Kerford和 Georgi提出的时序分析方法 ,利用相干技术定量地评价实测碳氧比能谱测井各比值曲线的重复性、信噪比、垂直分辨率等指标。实际应用表明 ,单探测器碳氧比能谱测井中的碳氧比、硅钙比、孔隙率指示比、铁指示比、矿化度指示比等曲线的质量好 ,可用于实际解释 ,但岩性指示比曲线、钙硅比曲线的重复性非常差 ,不能用于实际解释 ;双探测器比单探测器记录的碳氧比、硅钙比、孔隙率指示比、矿化度指示比等曲线的质量好 ,其中远探测器比近探测器记录的碳氧比能谱测井各比值曲线的质量好 。

The quality of carbon - oxygen ratio spectral logging curves not only depends on the characters and technical level of logging instrumentation itself,but also depends on the element contents of borehole and stratum as well as the impact of such factors as logging environment,logging speed and sample interval et al.Using the time series analysis method presented by Mr. Kerford and Georgi,the indexes ( repeatability,S/N ratio and vertical resolution ) of each ratio curve of real-tested carbon - oxygen ratio spectral log can be estimated quantitatively by using coherent technique.The practical application showed that carbon - oxygen ratio,silicon - calcium ratio,porosity indicator ratio,iron indicator ratio and salinity indicator ratio of carbon - oxygen ratio spectral log measured by single detector have good quality and can be used for practical interpretation,but lithology indicator ratio and calcium - silicon have bad repeatability and can't be used for practical interpretation;carbon - oxygen ratio,silicon - calcium ratio,porosity indicator ratio and salinity indicator ratio measured by double detector have better quality than that by single detector,among which the quality of carbon - oxygen ratio spectral logging curves measured by far detector is better than that by near detector,the quality of capture curves is better than that of non-elastic dispesive curves.