Simultaneous/Sequential Alkaline-Surfactant-Polymer flooding in Fractured/Non-Fractured Carbonate Reservoirs

摘要

Alkaline-Surfactant-Polymer flooding is one of the most novel chemical enhanced oil recovery methods in the petroleum industry. This method has attracted interest due to its remarkable advantages. In this work, a series of ASPf loods are conducted on fracturedon-fractured carbonate rocks. The performance of the tests was investigated by various ASP floods consisting of five types of polymers, two surfactants and one common alkaline. ASP was flooded simultaneously and sequentially in four defined scenarios after water flooding. The results showed that although using hydrolysed nolymers increases the recovery factor in the fractured medium, sulfonated polymers increase oil recovery even more due to their capability to increase viscosity in saline solutions. Also, since polymers with a higher molecular weight have a larger hydraulic diameter, they increase oil recovery considerably. Moreover, using cationic surfactant improves the efficiency of ASP flooding due to the serious reduction of interfacial tension (IFT) in comparison to using the anionic one. In addition, according to the four scenarios' results, pushing ASP by polymer is much more effective than pushing it with brine. Also, the difference in final oil recovery between simultaneous and sequential ASP floods is more remarkable when ASP is pushed by brine. Thus, choosing a process completely depends on the slug type and the injected volume.