基于太赫兹光谱的页岩有机质定量分析

Quantitative analysis of shale organic matter based on terahertz spectrum

摘要:

页岩是油气储层的主要类型之一，其微量有机质的准确表征是油气资源勘探中的一大热点和难点。利用太赫兹时域光谱技术(THz-TDS)对不同原油含量(ppm级)的页岩进行测试与分析，结果表明，太赫兹光谱响应与页岩有机质含量存在单调关系：随着原油浓度增加，单位厚度太赫兹时域光谱幅值衰减系数线性增加。结合有效介质理论，确定了太赫兹介电常数与200 ppm以下原油含量之间的线性关系。研究表明，太赫兹时域光谱技术可作为页岩中微量原油表征的有效方法，对提高油气资源勘探效率具有重要意义。

Abstract:

Shale is one of the main type of oil and gas reservoirs. The accurate characterization of trace organic matter is a hotspot and bottleneck in oil and gas exploration. Terahertz Time Domain Spectroscopy(THz-TDS) is employed to scan and analyze shale with different crude oil contents(ppm level). The results show that there is a monotonic relationship between THz parameter and the content of organic matter. With the increase of crude oil concentration, the attenuation coefficient of THz amplitude per unit thickness increases linearly. Combined with the theory of effective media, the linear relationship between THz dielectric constant and crude oil content below 200 ppm is determined. Therefore, THz-TDS can be used as an effective method for characterization of trace crude oil in shale, which is of great significance for the improvement of the exploration efficiency of oil and gas resources.