BIODIESEL AS SURFACTANT ADDITIVE IN STEAM ASSISTED RECOVERY OF HEAVY OIL AND BITUMEN

Solvents or surfactants are considered as additives to increase the efficiency of steam assisted heavy oil and bitumen recovery processes. Commercial use of solvents has setbacks due to their high costs and retrieval difficulties. We propose the use of biodiesel (BD) such as fatty acids methyl esters as a surfactant additive reducing heavy oil/bitumen‑water interfacial tension. Chemical stability under reservoir operating pressure and temperature, harmlessness on bitumen quality and water chemistry and low cost are the advantages of using biodiesel as a surfactant additive. The BD is produced as a byproduct by several companies and commercially available at amount of field scale applications. We conducted experiments to clarify the effect of biodiesel as a surfactant additive on recovery potential and efficiency of bitumen production. The porous media used was artificial loose sands saturated with a heavy oil of 3,000‑4,000 cp and surface mined oil sands. Laboratory tests performed exposing the sample to saturated steam under atmospheric and 1.8 MPa pressures with and without BD addition. In these tests BD was spread on oil sands samples and packed into the sample basket made of perforated walls. Laboratory data showed that BD addition at about 1 g‑BD/kg‑bitumen dosages resulted in significant increase in oil recovery. Further tests were performed by injecting BD into high pressure steam line. In these tests, BD derived from tall oil, i.e. tall oil fatty acids methyl ester was used; vapor pressure of which were measured to gain confidence that BD saturation concentration in steam is greater than its desired dosages. Remarkable increase in the recovery by steam injection with biodiesel addition was promising for further field testing also supported by relatively low cost of biodiesel compared to other surfactants.