This historical review addresses one topic in well logging. In 1983–85 special geophysical work was carried out in the Poinga area of the Vychegda oil shale basin (OSB) in the northeastern part of the East-European Platform, to search for oil shale deposits . The results of the study of Sysola oil shale by using the geophysical logging are presented. The density logging data was used to predict the calorific value of oil shale. It is shown that the elementary procedure of elimination of the regional component from the measured values of the gamma-gamma log provides an excellent correlation between the predicted and true calorific values of oil shale. The regional anomalies of gamma-gamma logging data were determined using the averaging method. The local anomalies of OS layers were calculated. In our calculations not the absolute values of the measured gamma-gamma logging parameter, but relative to average ones were used. So, the accuracy increased significantly and amounted to 87–91%.
1. Vassilieva, L. F., Dedeev, V. A., Duryagina, L. A., Captainov, V. M., Koloda, N. A., Konanova, N. V., Lavrenko, N. S., Lyyurov, S. V., Melnikova, L. A., Molin, V. A., Pavlov, A. M., Ptushko A. I. Oil Shale of the European North of the USSR. Komi Science Center, Urals Branch of the USSR Academy of Sciences, 1989, 152 (in Russian).
2. Arnold, D. M. Borehole compensated density logs corrected for naturally occurring gamma rays. U.S. Patent 4529877. Jul. 16, 1985.
3. Bardsley, S. R., Algermissen, S. Т. Evaluating oil shale by log analysis. J. Petrol. Technol., 1963, 15(1), 81–84.
4. Habiger, R. M. Determination of oil shale yield from well log data. U.S. Patent 4548071. Oct. 22, 1985.
5. Makarov, A. N., Loginov, M. I. Oil shale study in the Baltic basin by gamma-gamma logging tool using the single-scattered gamma radiation. Vestnik LSU, 1972, No. 6, 154–156 (in Russian).
6. Rider, M. H. Gamma-ray log shape used as a facies indicator: critical analysis of an oversimplified methodology. In: Geological application of wireline logs (A. Hurst, M. A. Lovell, A. C. Morton, eds.). Geological Society, London, Special Publication, 1990, 48, 27–37.
7. Kobrunov, A. I., Kuleshov, A. I., Mogutov, A. S., Hudojilova, A. N. Method of fuzzy petrophysical compositions when forecasting petrophysical parameters. Vestnik of Institute of Geology of Komi SC, RAS, 2011, No. 7, 3–13 (in Russian).8. Finol, J., Guo, Y. K., Jing, X. D. A rule based fuzzy model for the prediction of petrophysical rock parameters. J. Petrol. Sci. Eng., 2001, 29(2), 97–113.