The asphaltene fraction of crude oil is defined by its solubility parameters (insoluble in n-heptanebut soluble in toluene). Changes in conditions (temperature, pressure, solvent) can cause precipitation of asphaltenes leading to clogging of oil wells and pipelines and reduced productivity. Enhanced Oil Recovery (EOR) is increasingly being used to obtain the maximum amount of crude oil from a reservoir. One such technique involves the use of high pressure CO2 to force oil from the reservoir pores. However CO2 causes precipitation of asphaltenes. We intend to investigate this behaviour in a simplified model "oil" of asphaltenes dissolved in deuterated toluene. Using Zimm analysis and fitting to exact from factors we will estimate the size of the asphaltene nanoaggregates and find the point of precipitation under high pressures (up to 100 MPa) of CO2.