Abstract

The paper summarizes results of model studies of in-situ processes in heavy and extra-heavy oil reservoirs with differing geological and PVT characteristics developed by air injection. In terms of the mode of oil occurrence, two types of reservoirs with the original oil saturation values 0.4, 0.6, and 0.8 were considered, namely, reservoirs similar to those associated with the Sheshminskian formation dated to the Ufimian age, and reservoirs similar to those confined to the Bashkirian, the Visean, and the Tournaisian formations. For the former, the original oil viscosities from 1000 to 50,000 mPa·s were used in calculations, while for the latter, the original oil viscosity values ranged from 300 to 900 mPa·s. It was found that for the first type of reservoirs, with the original oil saturation 0.8 and zero free water at initial reservoir conditions, the time period between the start of air injection and the start of the formation temperature intensive growth is defined by the original oil viscosity. Based on the obtained oil recoveries, polynomial and power-law dependencies of oil recovery factor vs. initial reservoir conditions–depth of reservoir, in-situ viscosity, and original oil saturation–were built.

Key words:

heavy oil accumulation, extra-heavy oil accumulation, reservoir flow model, air injection, oil viscosity, average formation temperature, oil recovery factor

References

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Authors

R.Kh. Nizaev, Dr.Sc., Assistant Professor, Leading Research Associate, TatNIPIneft–PJSC TATNEFT
40, M.Djalil st., Bugulma, 423326, Russian Federation
E-mail: nizaev@tatnipi.ru

G.V. Aleksandrov, Junior Research Engineer, TatNIPIneft–PJSC TATNEFT
40, M.Djalil st., Bugulma, 423326, Russian Federation
E-mail: razrcmg@tatnipi.ru

Yu.L. Egorova, Senior Lecturer of Almetyevsk State Oil Institute
2, Lenin st., Almetyevsk, 423450, Russian Federation
E-mail: ulaegor@rambler.ru

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