| dc.description.abstract | Microwave heating as a thermal enhanced oil recovery (EOR) method has the potential to significantly reduce the total heating time of a reservoir and, consequently, the total cost of oil production. Success of microwave heating is controlled by the dielectric properties of the materials subjected to microwave radiation. Hence, this study investigates the dielectric properties of crude oil fractions, namely saturates, aromatics, resins, and asphaltenes (SARA) on microwave effectiveness of heavy oil extraction. In this study, three oil samples with distinct differences in API, viscosity, and SARA weight percentages were tested for their microwave heating effectiveness. Asphaltenes are defined as the most polar fraction within crude oil, so further investigation of its effect to crude oil absorption is merited. Upon oil fractionation through the ASTM method in conjunction with microwave heating, three major components of crude oil composition were investigated to maximize absorption in the oil phase: alteration of asphaltene polarity through various solvents, polar-polar interactions between resins and asphaltenes, and the temperature dependence of dielectric properties with respect to crude oil composition. Solvents selected comprised of two asphaltene precipitants (nC5 & nC7) and an asphaltene dispersant (toluene) were added to bulk crudes at discrete weight percentages (10%, 20%, and 50%). Dielectric property dependence on temperature was compared between the microwaved results and samples heated conventionally at various temperatures. A temperature dependence was connected to the bulk crude oils, where both the dielectric constant and loss tangent are more prone to increase when exposed to increased temperatures. Temperature correlations depicted that as the API increased for various oils, viscosity would necessarily decrease. Crude oils with the highest weight percentages of resins and asphaltenes (20.14%, 40.08%), lowest API (6.11), and highest viscosity (1.00E+07) led to the greatest increase in the dielectric constant, or polarity of the crude oil (2.26%). Conversely, oil samples with the highest light components in saturates and aromatics (30.03%, 41.84%), highest API (17.12%), and lowest viscosity (496) will produce the highest absorption difference in the loss tangent (121.54%). As it was found that the dielectric properties are highly sensitive to temperature, colloidal instability index should not be used as the main indicator of dielectric performance prediction. Microwaved results mostly echo that of the conventional results, but the difference in performance varied. Further research would necessitate altering various microwaving parameters such as the heating time and frequency to achieve desired results. The aforementioned correlations offers a fast and easy method to identify the potential of given crude oils for microwave heating. For the first time, heavy oil and its SARA fractionations were investigated on a deeper scale on how microwave absorption can be maximized. | |
