(145c) Studying the Effect of Stripping Light Hydrocarbons from Shale Oil Using Model Oil System

Wax deposition is a common and costly problem in oil industry, especially in pipelines, storage tanks, barges, and containers. Wax precipitation occurs when the temperature in the tanks fall below the cloud point or wax appearance temperature (WAT). WAT is dependent on many factors such as the rate of cooling, composition of the oil, cooling mechanism (quiescent or sheared cooling). Oils derived from shale formations often have both high vapor pressure and significant wax concentrations. Vapor pressure standards for transportation of crude oil requires the lighter ends stripped from oil. In this work, the effect of stripping light hydrocarbons on the WAT and the rheological property will be presented using a model-oil system. The lighter hydrocarbon used are pentane, hexane and heptane.  We determine the WAT, gelation temperature, yielding behavior for different shear histories, and creep recovery using a cone and plate system for the model oil system with and without the lighter hydrocarbons. In addition, polarized light microscopy is used to visually probe into the size and aspect ratio of the wax crystals formed at different conditions. A correlation is drawn between the stripping of lighter hydrocarbons and the change in WAT and other rheological properties.