Abstract: Reservoir B is the major oil production zone of Kuman Oilfield in Volga Basin, of which the oil in place accounts for 48.5% of the total. Research on the sedimentary features and heterogeneity of the reservoir is conducted, using the drilling, logging, and core data. Results show that the reservoir is tide delta and tide-delta sedimentary facies. The major oil layer (C1- Ⅴ and C1- Ⅵ) is dominated by dune ridges, while the non-major one is dominated by tidal channels, mudflat facies, and sandflat facies. The reservoir permeability variation coefficients range from 0.42 to 1.62, and the mutation coefficients are between 1.87 and 6.69. The permeability ratio is higher. The interlayer heterogeneity and the inner heterogeneity are strong, while the plane heterogeneity is weaker. Comprehensive evaluation shows that the C1- Ⅴ and C1- Ⅵ layers feature in stable plane distribution and good connectivity, and they are favorable for development. The C1- Ⅳ, C1- Ⅲ, and C1- Ⅱ layers feature in severe heterogeneity, small petroliferous area, and thin oil layers, and they are unfavorable for development.

Key words: Volga Basin, Kuman Oilfield, B reservoir, sedimentary feature, heterogeneity