Effect of the Component Composition of Oils on Their Structural and Mechanical Properties

In this paper oils related to paraffinic resinous and highly resinous and also low paraffin highly resinous oils, for which the group chemical composition, viscosity-temperature and structural-mechanical properties have been determined, were investigated. The internal energy for breakdown of the supramolecular structure (ΔW) of the oils was calculated from the isothermal curves for flow in the forward and reverse directions obtained at 10, 0, and -10°C. It was established that an increase of ΔW with decrease of temperature is observed for all the oils, and this is explained by the formation of an extended crystal lattice in the paraffinic hydrocarbons in the volume of the oil. It was shown that the degree of structurization of the oil system increases with increase of the total content of solid paraffinic hydrocarbons and asphaltenes (P + A) and with decrease of the proportion of resins (R). It was established that for the investigated oils at low temperatures the (P+A)/R value of 0.4 is a threshold value above which the oil exhibits thixotropic characteristics due to structurization of the system.