Experimental Investigation of the Steam Drive Process for the Asphalt Ridge Tar Sands Deposit, Utah

A series of laboratory experiments was conducted at the University of Wyoming to determine the steamflood recovery mechanisms for the Asphalt Ridge Tar Sands deposit located near Vernal, Utah. Steam at various temperatures and qualities, hot water and also nitrogen were injected into an adiabatic tube containing the tar sands, and the recovery curves were measured. From the results of the experiments, it was concluded that the Asphalt Ridge steamflood mechanisms consist of viscosity reduction, solvent extraction-enrichment, liquid displacement, and steam distillation. In addition to determining the steamflood mechanisms, it was also shown that, for the Asphalt Ridge Tar Sands (1) steam injection recovered more oil than did a hot waterflood at the same temperature (2) thick, viscous oil was produced during low quality steam runs, whereas a lighter oil was produced at higher qualities, and (3) intermediate quality steam will recover more of the original oil in place than will either high quality steam or hot water.