Enhancement of oil recovery by surfactant-induced wettability alteration

Document Type

Article

Publication Date

3-1-2006

Abstract

A study was carried out to determine the influence of surfactant type and concentration on oil recovery, oil-water relative permeabilities, and wettability in reservoir rocks. Coreflooding experiments were conducted using Yates reservoir fluids in Berea rocks and two types of surfactants in varying concentrations. A coreflood simulator was utilized to compute oil-water relative permeabilities by history matching the recovery and the pressure drop data obtained from the corefloods. Both the nonionic and anionic surfactants altered wettability of Berea rock-Yates reservoir fluids system in addition to reducing the oil-water interfacial tension. The optimum surfactant concentration was 3500 ppm for both types of surfactants used for oil recovery enhancement. Higher oil recoveries and the absence of oil-water emulsion formation were observed with the nonionic surfactant, while relatively lower oil recoveries and oil/water emulsions were observed with the anionic surfactant. Nonionic surfactant at 3500 ppm concentration was recommended as the most favorable surfactant type and concentration for the rock-fluids system. The capability of both these surfactants to develop a special kind of heterogeneous wettability known as mixed-wettability for potential oil recovery enhancements. Only two orders of magnitude reduction in interfacial tension obtained with both the surfactants suggested a relatively lower effect of interfacial tension reduction mechanism on improved oil recoveries.

Publication Source (Journal or Book title)

Saudi Aramco Journal of Technology

First Page

37

Last Page

44

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