Comparative Effectiveness of Alkaline Flooding and Alkaline鈥揝urfactant Flooding for Improved Heavy-Oil Recovery

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• 作者：Haihua Pei ; Guicai Zhang ; Jijiang Ge ; Mingguang Tang ; Yufei Zheng
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：May 17, 2012
• 年：2012
• 卷：26
• 期：5
• 页码：2911-2919
• 全文大小：908K
• 年卷期：v.26,no.5(May 17, 2012)
• ISSN：1520-5029

文摘

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鈥搒urfactant (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.