Raman characteristics of hydrocarbon and hydrocarbon inclusions

Abstract

The Raman spectrograms of hydrocarbon standard samples show that: (1) the Raman spectrogram of normal paraffin has very strong peaks of methyl and methylene (from 2700 cm −1 to 2970 cm −1 ); (2) branch methyl has the particular peak of 748 cm −1 ±; (3) six cyclic has the particular peak of 804 cm -1 ±; (4) phenyl has two particular peaks of 988 cm −1 ± and 3058 cm −1 ± and the 988 cm -1 ± peak is stronger than the 3058 cm −1 ± peak; and (5) hexene has three alkenyl spectrum peaks of 1294 cm −1 ±, 1635 cm −1 ± and 2996 cm −1 ±, with the 1635 cm −1 ± peak being the strongest, showing that the number of carbon in hydrocarbon does not affect its Raman spectrogram, and the hydrocarbon molecular structure and base groups affect its Raman spectrogram, the same hydrocarbons (such as normal paraffin) have the same Raman spectrogram; the types (such as CH 4 , C 2 H 6 , C 3 H 8 ) and the content of hydrocarbon in oil inclusions are not estimated by their characteristic Raman peaks. According to the Raman spectrograms of hydrocarbon compositions, the Raman spectrogram of hydrocarbon inclusion can be divided into five types: saturated hydrocarbon Raman spectrogram, fluoresce Raman spectrogram, saturated hydrocarbon bitumen Raman spectrogram, bitumen Raman spectrogram, and ethane Raman spectrogram. And according to the characteristics of Raman spectrogram, hydrocarbon inclusions can be divided into five types: saturated hydrocarbon inclusion, less saturated hydrocarbon (oil or gas) inclusion, saturated hydrocarbon bitumen inclusion, bitumen inclusion, and methane water inclusion.

Sample maturation calculated using Raman spectroscopic parameters for solid organics: Methodology and geological applications

“…Shown in Figure 1 is a Raman spectrum of powdered graphite manufactured by Guangzhou Xingang Chemical Engineering Co. Ltd., which clearly shows the Raman shift values for peak "D", peak "G" and the divalent overtone (G′). He et al [13], Zhang et al [14], Zhang et al [15], and Liu et al [16] studied the Raman spectra of bitumen and bitumen-bearing hydrocarbon inclusions in oil reservoir, and identified Raman peak D and peak G indicative of bitumen; Liu et al [17] and Liu et al [18] studied the high density methane inclusions derived from pyrolysis of oil inclusions in Puguang gas field in Sichuan, and also identified Raman peak D and peak G as well as divalent peak bulge (G′) indicative presence of pyrobitumen in methane inclusions; Zeng and Wu [7] performed systematic Raman measurement of kerogen simulation samples at 50-100 MPa and 250-700°C, while Kelemen and Fang [6] carried out comprehensive Raman spectroscopic study of coal and kerogen of different maturation, and their results all suggest that: with increasing maturation of samples, peak "D" would shift to lower frequency at ca. 50 cm 1 , but to high frequency at not more than 10 cm 1 , the inter-peak interval between peak D and peak G is closely related to vR o of experimental sample, and the widths of both peak "D" and peak "G" and the area ratio between these two peaks are all decreased with increasing reflectance.…”

Organic inclusions evidence, composition, and cathodoluminescence behaviour for the formation conditions of fluorapatite from Anemzi (Morocco)

“…The broad Raman bands in the region 1,600–1,200 cm −1 are attributed to bending vibrations of CH 2 and CH 3 groups in aliphatic compounds . On the RS spectrum of the fluid inclusion, extra bands at 1,667–1,659 and 1,781 cm −1 are observed, due to stretching vibrations in the CC groups …”

“…Another inclusion analysed within apatite also revealed the presence of organic components (Figure ). The existence of a strong band in the region 2,800–3,000 cm −1 shows that the inclusion has the most saturated hydrocarbon composition . The broad Raman bands in the region 1,600–1,200 cm −1 are attributed to bending vibrations of CH 2 and CH 3 groups in aliphatic compounds .…”

“…A Raman system, coupled with a confocal microscope, enable to analyse single, unique inclusions found below the surface of the host gem nondestructively. However, the determination of hydrocarbon‐bearing inclusions, which are of remarkable importance from a scientific and economic point of view, is a difficult task because of their chemical complexity and high fluorescence background …”

“…However, the determination of hydrocarbon-bearing inclusions, which are of remarkable importance from a scientific and economic point of view, is a difficult task because of their chemical complexity and high fluorescence background. [12][13][14] In our study, we describe the textural and compositional evolution of apatite from nepheline syenite from Anemzi (Morocco) in order to provide insight into the evolution of its parental magma. Moreover, the detailed data on organic fluid and solid inclusions present in the whole volume of apatite gems were provided to discuss the composition of fluids during apatite's formation.…”