Аннотации:
This chapter presents the definition and classification of crude oils according to their constituents and describes the main properties used to characterize them. Basically, heavy crude oil has a much higher viscosity and density than conventional crude oil and generally has sulfur content higher than 2 wt%. The importance of certain physical properties has been highlighted for the classification of crude oil and complications of recovery from reservoirs. Physical properties such as density, viscosity, and pour point may vary widely in crude oils from different locations. Chemical properties are indispensable to know the quality of heavy or extra-heavy crude oils in order to evaluate the refining capacity likewise the type of products generated. Heavy crude oils from different origins present similar ranges of properties because they are characterized as viscous liquids with high content of heteroatoms providing low API gravity values.