Poorly recoverable oils are typified on the basis of analysis and generalization of the published data. An oil quality index that allows investigation of the characteristics of poorly recoverable oil reserves is proposed. Types of poorly recoverable oils are classified in terms of quality index into three classes, namely, low-, medium-, and high-quality oils. The peculiarities of physicochemical properties of poorly recoverable low-, medium-, and high-quality oils are determined by analyzing data on 18,000 specimens of oils having anomalous properties and 9000 specimens of oils bedded under complex conditions. A comprehensive classification of oils based on physicochemical properties is proposed, taking account of the density, viscosity, sulfur, resin, asphaltene, solid paraffin, vanadium, nickel, and light fraction content, gas saturation of the oil, etc. The investigation results can be used for optimizing the routes of transporting oils having anomalous physicochemical properties through pipelines.