Composition of Oils of Carbonate Reservoirs in Current and Ancient Water—Oil Contact Zones

• Published in: Chemistry and technology of fuels and oils 2015, Vol.51 (1), p.117-126
• Main Authors: Kayukova, G. P., Morozov, V. P., Islamova, R. R., Nosova, F. F., Plotnikova, I. N., Petrov, S. M., Vakhin, A. V.
• Format: Article
• Language: English
• Subjects: Adsorption; Carbonates; Chemistry; Chemistry and Materials Science; Geotechnical Engineering & Applied Earth Sciences; Industrial Chemistry/Chemical Engineering; Methods of Investigation of High-Viscosity Oils; Mineral Resources
• ISSN: 0009-3092; 1573-8310
• DOI: 10.1007/s10553-015-0583-z

Differences in the composition of heavy oils from ancient and current water—oil contact (WOC) zones of productive strata of carbonate reservoirs of deposits of Bashkir and Turnei (Tatarstan) stages are discerned by applying a host of physicochemical methods, namely, elemental analysis, liquid-adsorption chromatography, gas chromatography, IR spectroscopy, and EPR spectroscopy. There is no direct connection of the composition of the hydrocarbons with the secondary changes of the reservoirs and their filtration-capacity parameters. Signs of seepage of light hydrocarbons are detected in the ancient WOC zones characterized by the presence of products of biochemical degradation of high-molecular-weight components of residual oil. This provides a basis for suggesting that these zones are not only fluid-supports but also migration channels for interstratal seepages of hydrocarbons during formation and development of oil reservoirs.