湖南雪峰山地区干酪根的拉曼光谱研究

Laser Raman microspectrometry of the marine kerogen samples from the Xuefengshan area in Hunan

关键词:  干酪根  拉曼光谱  镜质体反射率

Key words:  kerogen  Raman microspectrometry  vitrinite reflectance

摘要:

干酪根是沉积有机质的主体,是石油地质工作研究的重要对象,目前利用激光拉曼光谱进行干酪根的研究较少。雪峰山地区干酪根的拉曼光谱测试结果表明:干酪根的一级拉曼光谱峰位差与镜质体反射率之间有着系统的规律性变化,在Ro<2.4%时,峰位差随Ro的增大迅速增大,其相关系数为0.82;Ro在2.4%~2.9%之间时,二者关系不明显,离散度较大;Ro>2.9%时,峰位差随Ro的增大逐渐减小,相关系数为0.88。镜质体反射率是衡量有机质成熟度和热演化程度的重要指标,干酪根的拉曼光谱特征与镜质体反射率之间的关系表明激光拉曼光谱法可以成为有机质成熟度和热演化程度研究的新方法。

Abstract:

The examination of the marine kerogen samples from the Xuefengshan area, Hunan was carried out by a laser Raman microspectrometer. There are two distinct vibration peaks G and D in the wave number range of 1000-2000cm^-1. The distances between the peaks G and D display regular changes, as a function of vitrinite reflectances (Ro). Within the vitrinite reflectances Ro<2.4%, the distance between the peaks G and D rapidly increases in response to the increase of vitrinite reflectances. In this instance, the correlation coefficient is 0.82. No marked relationship was observed when the vitrinite reflectances range between 2.4% and 2.9%. The distance between the peaks G and D gradually decreases as the vitrinite reflectances Ro>2.9%. In this instance, the correlation coefficient is 0.88. It follows that the vitrinite reflectances may be an important index of organic maturity and thermal evolution. The relationship between the Raman spectra and vitrinite reflectances indicates that the laser Raman microspectrometry may be employed as a new technique suitable for the examination of organic maturity and thermal evolution of sedimentary organic matter.