Composition and physico-chemical properties of high-viscosity oil of Varadero oil field (Cuba)

UDK: 622.276.1/.4:665.61
DOI: 10.24887/0028-2448-2019-9-34-37
Key words: group composition of oil, asphaltenes, resins, resins and asphaltenes molecular weight distribution, phase stability of asphaltenes, rheology of water-oil emulsion
Authors: A.I. Voloshin (RN-BashNIPIneft LLC, RF, Ufa), V.A. Dokichev (RN-BashNIPIneft LLC, RF, Ufa), A.V. Fahreeva (Ufa Institute of Chemistry, Ufa Federal Research Centre of RAS, RF, Ufa), M.R. Yakubov (A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of RAS, RF, Kazan), Yu.V. Tomilov (Ufa State Aviation Technical University, RF, Ufa)

Methods of FTIR spectroscopy, NMR and MALDI mass-spectrometry were used to study asphaltenes, resins and oil of the Varadero oil field (Cuba). We determined the content of macro elements of oil: С = 76.11, H – 9.32, N – 0.56 and S– 8.35 %, the content of metal V and Ni in the oil 0,0103 and 0,0064% , in asphaltene 0,029 and 0.022 % respectively. The most probable molecular masses of resins and asphaltenes were established which amounted to 765 and 929 atomic units respectively. The features of the structural-group composition and molecular characteristics of oil, asphaltenes and resins are revealed. According to the spectral coefficients obtained from the IR-Fourier spectra, oil and resins of the Varadero oilfield have high aliphaticity, branching, condensation, oxidation and sulfur content; in addition, the resins have a relatively high content of carboxyl, sulfoxide and sulfonic groups. Asphaltenes are highly aromatic, aromatic compounds mainly have a condensed structure and are paramagnetic. According to 1H and 13C NMR spectroscopy, the ratio of alkyl group protons and aromatic fragments was found to be 12.6:1. Asphaltenes in oil are unstable, having a high colloidal instability index – 1.24, in the conditions of formation and production are able to stabilize the water-oil emulsion (WNE) and form solid deposits. Rheological method shows that at a temperature of 21 °C there is a structural reorganization of VNE. Temperature dependences in the temperature ranges from 10 to 21 °C and from 21 to 40 °C obey the Arrhenius equation. The activation energy of the viscous flow in the first temperature range is 44.3 kJ/mol, and in the second – 61 kJ/mol.


1. Danilova E., Heavy oils of Russia (In Russ.), The Chemical Journal, 2008, no. 12, pp. 34–37.

2. Speight J.G., Heavy and extra-heavy oil upgrading technologies, Houston, TX, USA: Gulf Professional Publishing, 2013, 137 р.

3. Speight J.G., Petroleum asphaltenes. Part 1: Asphaltenes, resins and the structure of petroleum, Oil & Gas Science and Technology, 2004, V. 59, pp. 467–477.

4. Wieh I.A., Kennedy R.J., The oil compatibility model and crude oil incompatibility, Energy & Fuels, 2000, V. 14 (1), pp. 56–59.

5. Gonzalez B.M., Barrionuevo S., Peralba M.C., Kalkreuth W., Geochemical characterization of Jurassic source rocks from Cuba: 2. Constancia formation in onshore Varadero oils fields, Energy Exploration & Exploitation, 2014, V. 32, no. 5, pp. 847–872, DOI:10.1260/0144-5987.32.5.847.

6. Ryl'kov A.V., Poteryaeva V.V., Global naphthene-base crudes (propagation, genesis, application) (In Russ.), Izvestiya vuzov. Neft' i gaz, 2013, V. 97, no. 1, pp. 32–44.

7. Yakubova S.G., Manaure D.A., Machado R.A. et al., Effect of oxyethylated isononylphenol (neonol) on viscosity characteristics of water-oil emulsions, Petroleum Science and Technology, 2018, no. V. 36, no. 17, pp. 1389–1395, DOI:10.1080/10916466.2018.1482318.

8. Conaway C., The petroleum industry: A nomenclature guide, Tulsa: Pennwell Publ. Co., 1999, 289 р.

9. Yakubov M.R., Milordov D.V., Yakubova S.G., Borisov D.N., Ivanov V.T., Sinyashin K.O., Concentrations of vanadium and nickel and their ratio in heavy oil asphaltenes (In Russ.), Neftekhimiya = Petroleum Chemistry, 2016, V. 56, no. 1, pp. 19–23.

10. Rakhmatullin I.Z., Efimov S.V., Margulis B.Ya., Klochkov V.V., Qualitative and quantitative analysis of oil samples extracted from some Bashkortostan and Tatarstan oilfields based on NMR spectroscopy data, J. Petrol. Sci. Eng., 2017, V. 156, pp. 12–18, DOI: 10.1016/j.petrol.2017.04.041.

11. Petrova L.M., Abbakumova N.A., Borisov D.N. et al., Influence of component contents and structure characteristics of the components on heavy oils stability to asphaltene precipitation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 1, pp. 74–76.

12. GuzmГЎn R., Ancheyta J., Trejo F., RodrГ­guez S., Methods for determining asphaltene stability in crude oils, Fuel, 2017, V. 188, pp. 530–543, DOI: 10.1016/j.fuel.2016.10.012.

13. Gusakov V.N., Kashtanova L.E., Nazarova S.V. et al., Design of technologies for processing bottom-hole zone of Varadero oilfield (Cuba) (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 12, pp. 126–130.

14. Zadymova N.M., Skvortsova Z.N., Traskine V.Yu. et al., Rheological properties of heavy oil emulsions with different morphologies, J. Petrol. Sci. Eng., 2017, V. 149, pp. 522–530.

15. KeleЕџoДџlu S., Pettersen B.H., SjГ¶blom J., Flow properties of water-in-North Sea heavy crude oil emulsions, J. Petrol. Sci. Eng., 2012, V. 100, pp. 14–23.

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