Study of Organic Matter of Unconventional Reservoirs by IR Spectroscopy and IR Microscopy

Abstract

The study of organic matter content and composition in source rocks using the methods of organic geochemistry is an important part of unconventional reservoir characterization. The aim of this work was the structural group analysis of organic matter directly in the source rock in combination with a quantitative assessment and surface distribution analysis of the rock sample by FTIR spectroscopy and FTIR microscopy. We have developed new experimental procedures for semi-quantitative assessment of the organic matter content, composition and distribution in the source rocks and applied these procedures for the study of the samples from the Bazhenov shale formation (West Siberia, Russia). The results have been verified using the data from the study of organic matter obtained by Rock-Eval pyrolysis and differential thermal analysis. The obtained results demonstrate the prospects of FTIR spectroscopy and FTIR microscopy application for non-destructive and express analysis of the chemical structure and distribution of organic matter in rocks.

Supercritical methane adsorption measurement on shale using the isotherm modelling aspect

“…In addition, absorption bands were identied by comparison with published spectra. [89][90][91] In this study, the estimated proportion obtained by visual comparison of the peaks measured from 3000-2800 cm À1 is related to the aliphatic C-H stretching region, and from 1700 to 1500 cm À1 is attributed to the presence of oxygen-containing bonds C]O for oxygenated groups and aromatic/olenic region. In addition, peaks were also observed at 1375-1450 cm À1 indicating CH 2 and CH 3 bending modes and at 700- FTIR of spectra of kerogens with increasing maturity exhibit increasing aromatic absorption (700-900 cm À1 ), decreasing in aliphatic absorption (3000-2800 cm À1 , 1375-1450 cm À1 ) and decreasing in carbonyl and carboxyl absorption (1700 to 1500 cm À1 ).…”

Organic Matter and Mineral Composition of Silicate Soils: FTIR Comparison Study by Photoacoustic, Diffuse Reflectance, and Attenuated Total Reflection Modalities

“…The applications of IR spectroscopy for soils are widespread and primarily oriented to humic substances [20][21][22][23][24][25], the total SOM or soil organic carbon [26,27], the texture and mineralogy of clay minerals and their organomineral complexes [28,29], or the availability of artificial additions such as nutrients or fertilizers [30,31]. In addition, IR spectroscopy is used to evaluate fertility, structuration, or biological activity of soils, as well as organomineral complexes, taking IR spectra as indicators of these properties [26][27][28][29]32]. Soil identification by its IR spectra has been developed [31,[33][34][35][36][37].…”

“…Therefore, IR spectroscopy in soil analysis is based on other modalities [18,34,42,43]. First, diffuse reflection IR Fourier-transform (DRIFT) spectroscopy is widely used to analyze and assess soils and organomineral complexes [18,19,26,28,[43][44][45][46][47]. However, the soil particle size profoundly impacts DRIFT spectra, as the size dispersion and particle distribution affect the reflection and may result in high measurement errors [45,48], even for the same types of soil samples.…”

A Summary of “Petrophysics and Geochemistry of Unconventional Reservoirs”

“…Much attention is paid to the study of the kerogen chemical structure [7], variation of kerogen type on the depth [8], the interaction of the organic matter and mineral matrix [9], void space [10], and the kerogen-related multiscale heterogeneity and anisotropy [11] of the Bazhenov formation sediments.…”

“…Tanykova et al [7] present results of kerogen chemical structure analysis directly in the Bazhenov Formation source rocks (West Siberia, Russia). The authors have developed new experimental procedures for semi-quantitative assessment of the organic matter content, composition, and distribution in the source rocks based on Fourier transform infrared (FTIR) spectroscopy in transmission and ATR modes, as well as FTIR microscopy of the rock surface.…”