The chemical composition of crude oils from five fields of Volgograd oblast has been studied. It has been shown that predicting the low-temperature properties of oil and for selecting asphaltene-resin-paraffin deposition inhibitors requires a more profound knowledge of the hydrocarbon composition of oil in addition to the structural-group composition. The presence of produced water in the produced well fluid increases the amount of asphaltene-resin-paraffin deposits.