Bitumen Recovery by the Steam-Over-Solvent Injection in Fractured Reservoirs (SOS-FR) Method: An Experimental Study on Grosmont Carbonates

We adapted the previously introduced SOS-FR (Steam-Over-Solvent Injection in Fractured Reservoirs) method and conducted 12 experiments using preserved core samples from the Grosmont formation. The method applied in this study is based on soaking rather than continuous injection. The samples were immersed in hot water (90 °C), first to mimic low-temperature presteaming to condition the reservoir for solvent injection. This was followed by a solvent soaking period under varying conditions (duration, solvent type, etc.). Heptane and the distillate obtained from a heavy oil upgrading facility were used as solvents. Finally, the core samples were soaked in hot water again. Oil recoveries varied between 40% and 90% OOIP, with a mean value of 68%. Asphaltene precipitation, as a percentage of original oil in place (OOIP), was measured between 6.5 wt % and 33 wt %. The oil recovery and asphaltene precipitation depended on the solvent type, the solvent exposure duration, the position of matrix rock (horizontal or v...