Application of Ultrashort Hydrophobe Surfactants with Cosolvent Characters for Heavy Oil Recovery

Abstract

A new class of ultrashort hydrophobe surfactants with cosolvent characters was investigated as a sole additive to conventional polymer flooding for heavy oil recovery. No alkali was used for emulsification. The surfactants were composed of a short hydrophobe (phenol in this research) extended by propylene oxide (PO) and ethylene oxide (EO) units to achieve a sufficient level of surface activity and aqueous stability: phenol-xPO-yEO. Results are presented for the selection of ultrashort hydrophobe surfactants, aqueous stability, emulsion phase behavior, and oil displacement through a glass-bead pack at 368 K. Results show that 2 wt % phenol-4PO-20EO was able to reduce the interfacial tension between oil and NaCl brine to 0.39 dyn/cm, in comparison to 11 dyn/cm with no surfactant, at 368 K. Water flooding, 40 cp polymer flooding, and surfactant-improved polymer flooding were conducted for displacement of 276 cp heavy oil through a glass-bead pack that represents the clean-sand facies of a heavy oil reservoir in Alberta, Canada. The oil recovery after 2.0 pore volumes of injection (PVI) was 84% with the surfactant-improved polymer flooding, which was 54 and 22% greater than the water flooding and the polymer flooding, respectively. Results suggest a new opportunity of enhanced heavy oil recovery by adding a slug of one nonionic surfactant with cosolvent characters to conventional polymer flooding.

Comparative Study of Ketone and Surfactant for Enhancement of Water Imbibition in Fractured Porous Media

“…The PO and EO groups affect the hydrophobicity and aqueous stability of the surfactant, respectively. Although other ultrashort hydrophobe surfactants were studied previously for improving polymer flooding by Baek et al, 2-EH– x PO– y EO surfactants are studied for the first time as a simple surfactant solution for enhancing water imbibition in fractured media in this research …”

Low-Tension Polymer Flooding Using a Short-Hydrophobe Surfactant for Heavy Oil Recovery

“…Recently, short-hydrophobe surfactants were studied by several researchers. − Wang et al tested a short-hydrophobe surfactant as a wettability modifier for oil recovery from fractured limestone cores . They found that 2-etheylhexanol-4PO-15EO (or 2-EH-4PO-15EO) altered the wettability of calcite surfaces from oil-wet (contact angle: 134.1°) to water-wet (contact angle: 47.1°) after 1 day.…”

“…Baek et al tested phenol-4PO-20EO for heavy oil recovery in a high-permeability glass-bead pack . They conducted water flooding, 40-cp polymer flooding, and low-tension 40-cp polymer flooding to displace a 276-cp heavy oil.…”

“…Baek et al tested phenol-4PO-20EO for heavy oil recovery in a high-permeability glass-bead pack. 9 They conducted water flooding, 40-cp polymer flooding, and low-tension 40-cp polymer flooding to displace a 276-cp heavy oil. The oil recovery after 2 PV injection was 84% with the LTP flooding, which was 54% and 22% higher than the water flooding and the polymer flooding, respectively.…”

“…In this research, LTP flooding was tested in oil displacements specifically designed for a heavy oil reservoir, where an economic optimum yielded a polymer viscosity that is substantially smaller than the oil viscosity. Unlike Baek et al, 9 an optimal short-hydrophobe surfactant was studied by exhaustive IFT measurements because the water−oil IFT is the key to achieving capillary desaturation and delayed the polymer breakthrough in LTP flooding. Also, this paper presents new experimental results of surface adsorption and equilibrium partition coefficients of the short-hydrophobe surfactant used for LTP.…”