Theoretical and physical modeling of vapour extraction heavy oil recovery

In this thesis, an analytical model is developed to predict the accumulative heavy oil production in the entire vapour extraction (VAPEX) heavy oil recovery process. This model is validated by comparing the theoretically predicted accumulative heavy oil productions and the experimentally measured data. In the experiment, a total of seven VAPEX tests are conducted to recover a heavy oil sample from a visual rectangular sand-packed high-pressure physical model and study the detailed effects of the permeability, horizontal well spacing and solvent volume injection rate on the VAPEX heavy oil recovery process. More specifically, the effects of the above-mentioned three important parameters on the accumulative heavy oil production, produced solvent-oil ratio (SOR), and asphaltene content of the produced oil are examined. It is found that the accumulative heavy oil production is increased with the permeability and solvent volume injection rate, whereas it is reduced with the horizontal well spacing. It is also found that the produced SOR is increased but the asphaltene content of the produced oil is reduced at a reduced permeability or an increased horizontal well spacing. However, an increased solvent volume injection rate causes both the produced SOR and the asphaltene content of the produced oil to increase.;Theoretically, a mathematical model is formulated to predict the accumulative heavy oil production data at different times. In this model, it is assumed that the transition zone between the solvent chamber and the untouched heavy oil zone has two straight-line boundaries with a constant thickness during the VAPEX process. The constant transition-zone thickness is used as an adjustable parameter and thus determined by finding the best fit of the theoretically predicted accumulative heavy oil production data to the experimentally measured data. It is found that variations of the transition-zone thicknesses determined by using the accumulative heavy oil production data at different times are relatively small for the conducted VAPEX tests. This fact indicates that the constant transition-zone thickness assumption is reasonable. In addition, it is also found that in general, the transition-zone thickness is increased when the permeability of the VAPEX physical model is decreased.