Известия Томского политехнического университета: Инжиниринг георесурсов (Mar 2019)

COMPOSITION OF FLUID INCLUSIONS BY RAMAN SPECTROSCOPY IN PALEOZOIC CARBONATE ROCKS OF SEVERO-OSTANINSK FIELD, WESTERN SIBERIA

  • Lyubov A. Krasnoshchekova,
  • Aura S. García,
  • Vladimir B. Belozerov

DOI
https://doi.org/10.18799/24131830/2019/3/178
Journal volume & issue
Vol. 330, no. 3
pp. 187 – 203

Abstract

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The relevance of the research is related to the possibility of detecting hydrocarbon deposits in the Paleozoic carbonate sediments of Western Siberia and increasing the oil and gas potential of the region. The aim of the research is to determine the composition of gas-liquid inclusions in dolomitized carbonate rocks of Severo-Ostaninsk oil field using Raman spectroscopy, which will allow clarifying information on fluid composition and conditions of formation of secondary dolomites in limestone, due to their association with oil and gas accumulation zones. The research object is the carbonate deposits in the roof part of the pre-Jurassic basement in Severo-Ostaninsk area of Western Siberia. Methods: petrographic (crystal optics), Raman spectroscopy and UV photoluminescence analysis. Results. The well section of the Severo-Ostaninsk field is composed of organogenic-oolitic limestone and dolomite of varying grain size. The petrographic study of carbonate rocks allowed distinguishing main phases of dolomitization in limestones: primary pelitomorphic material composing rock matrix together with calcite; secondary crystalline dolomite fulfilling fractures; and dolomite forming partially regular rhombohedral crystals. On a specific material, it was shown that using the Raman spectroscopy method, it was possible to detect in the gas-liquid inclusions of secondary dolomites spectral peaks at 1187, 1243, 1348 cm–1 typical of kerogen-containing organic matter, and peaks at 1525 and 1597 cm–1 characteristics of highly disordered carbon-containing material. The origin of these peaks are generated by Caromatic–Calkyl vibrations; aromatic ethers, C–C and C–H in aromatic rings. The contribution from C=O vibration was established as well. The presence of gas phases in the inclusions suggests that secondary dolomite in carbonate rocks was formed in the presence of carbonaceous matter dissolved in the rock-forming fluid.

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