Raman Spectra Characteristics of Fluid Inclusion in the Shaanxi Formation of the Dingbian Area in the Ordos Basin

Abstract

Raman Spectroscopy is an important means of non-destructive fluid inclusions analysis. Composition of fluid inclusions in quartz from the Shaanxi formation of the Dingbian area in the Ordos Basin was determined by the Raman technique. These inclusions show two kinds of Raman spectra, fluorescence-type Raman spectra which indicate aromatic hydrocarbon and saturated hydrocarbon-type Raman spectra which indicate saturated hydrocarbon. According to these two kinds of Raman spectra, the conclusion is that the fluid inclusions were possibly captured during the stage of hydrocarbon generation of coal hydrocarbon source rocks. Peaks of 2250 cm-1± and 2945 cm-1± are the main Raman peaks in the quartz overgrowths during stages Ⅰ and Ⅱ. The inclusions in cracks not only have the same peak with those in quartz overgrowths, but also show multiple Raman peaks between 600 and 1500 cm-1. This indicates that two kinds of fluid inclusions exist in different evolution stages of the coal source rocks with different compositions. The Raman spectra reveal the main composition of fluid inclusions in the Shaanxi Formation of the Dingbian area in the Ordos basin and reflect the composition changes during capture of fluid inclusions. It is of great significance to determine the relationship between the fluid formation environment at that time and the evolution of the coal hydrocarbon source rocks.

Keywords

• fluid inclusion in ordos basin
• fluorescence-type raman spectrum
• saturated hydrocarbon-type raman spectrum
• aromatic hydrocarbon
• saturated hydrocarbon