A novel technique for heavy oil recovery using poly vinyl alcohol (PVA) and PVA-NaOH with ethanol additive

A novel enhanced oil recovery approach using PVA solution and PVA-NaOH mixtures (with ethanol additives) to instigate in situ oil-in-water (O/W) emulsion of heavy oil is presented, for first time, in this paper. Polyvinyl alcohols (PVA) is the world's largest volume synthetic polymer, which has attracted several industrial applications because of its attractive properties including water solubility, surface activeness, chemical and thermal resistance, biocompatibility and biodegradability. In the present study, an experimental setup was developed to investigate tolerance to salinity, thermal stability, and to obtain optimal mixture formulation of PVA and PVA-NaOH (with ethanol additive) for emulsification of heavy oil. Subsequently, coreflooding experiments were performed to compare the recovery performances of water flooding, and those of (0.5%) PVA solution, PVA-NaOH mixture (pH = 12, EtOH = 0) designated PVA(x), and PVA-NaOH mixture (pH = 12, EtOH = 10% v/v) designated PVA(y). The results revealed that the PVA solution was used within 0–70,000 ppm salinity with no significant alteration to its surface activeness and/or emulsification ability. The PVA solution was applied within 25–175 °C with no significant alteration to its effectiveness. Positive synergistic results were obtained from PVA(x), and heavy oil emulsification was enhanced (with higher viscosity reduction) when PVA(y) was applied. By injecting 5.2 PV of PVA(y) (at 70 °C), 83% original oil in place (OOIP) of the highly viscous oil (1.5E + 5 cP at 30 °C) was recovered compared to 73% OOIP and 71% OOIP recovered using PVA(x) and PVA solutions, respectively.