Comparative Effectiveness of Alkaline Flooding and Alkaline–Surfactant Flooding for Improved Heavy-Oil Recovery

Abstract

Chemical flooding is a promising technique for enhanced heavy-oil recovery, especially for reservoirs where thermal methods are not feasible. This paper discusses results of a laboratory investigation, including sandpack flooding experiments and micromodel flooding studies, for assessing the suitability and effectiveness of alkaline flooding and alkaline−surfactant (AS) flooding for heavy-oil recovery. The sandpack flood results show that the tertiary oil recovery of AS flooding is lower than those of alkaline-only flooding, although the interfacial tension between the heavy oil and AS system can be reduced to be ultralow. The micromodel tests indicate that the mechanisms for enhanced oil recovery by alkaline flooding are the penetration of the alkaline solution into the crude oil and the subsequent formation of water-in-oil (W/O) droplet flow that tend to reduce the mobility of the water phase and damp viscous fingering, leading to the improvement of sweep efficiency. However, the formation of W/O droplet flow is inhibited with the addition of surfactant, and the viscous oil is easily emulsified into the water phase to form oil-in-water emulsions and then entrains along with the flowing aqueous phase. As a result, viscous fingering phenomena occur during the AS flooding, resulting in a relatively lower sweep efficiency.

Comparative effectiveness of production performance of Pickering emulsion stabilized by nanoparticle–surfactant–polymerover surfactant–polymer (SP) flooding for enhanced oil recoveryfor Brownfield reservoir

“…The pressure drop is also directly related to the viscosity of flood system. Higher the viscosity of flood, higher will be the pressure drop (Pei et al, 2012).…”

“…Some studies demonstrated that the surfactant in the presence of other chemicals encouraged additional oil recovery by improving the efficiency of the process. Pei et al (2012) have observed that the presence of surfactant in alkaline-surfactant (AS) flooding is promising technique for additional oil recovery due to stable oil displacement and significant reduction in the mobility of water phase and viscous fingering. Jang and Chon (2014) observed that the addition of small amount of surfactant of 0.1 pore volume (PV) in a total slug volume of 0.6 PV for surfactant-polymer (SP) flooding leads to the highest additional recovery of oil (28.6%) over water flooding.…”

Investigation of synergy between nanoparticle and surfactant in stabilizing oil-in-water emulsions for improved heavy oil recovery

“…The formula of surfactant-stabilized emulsion flooding is 0.1 wt% CTAB, and the formula of nanoparticle-surfactant stabilized emulsion flooding is 0.1 wt% CTAB +0.4 wt% N20. With these tests, the incremental oil recoveries of different emulsion flooding 8 were compared, and the effects of surfactant and nanoparticle on oil recovery were also examined.…”

“…On the other hand, in some other situations emulsions help to entrain the oil into the flowing aqueous phase [6][7][8][9]. Both the conditions lead to improved sweep efficiency after water flooding.…”

Pore Scale Dynamics of Microemulsion Formation

“…In oil-bearing reservoirs, following a waterflood where water is injected into the reservoir to displace oil to the production well, a large fraction of the oil remains in the water-swept region of the porous reservoir rock [13][14][15][16][17] . The injected aqueous phase preferentially flows through the connected water path that surrounds the oil phase trapped by capillary forces.…”