Study on Detection Method of Surfactant Content in Produced Fluid of Dagang Oilfield

Abstract At present, Dagang Oilfield is exploring the technology of surfactant-assisted shale oil stimulation and enhanced oil recovery (EOR). However, it is still a challenge to accurately characterize the distribution of surfactants in the reservoir and analyze the concentration of surfactants in the produced fluid of shale oil in the field. In this study, an effective method based on interfacial tension (IFT) to detect the content of surfactant in oilfield produced fluid was reported. The standard curve and linear equation between IFT and surfactant concentration (c) were established. At a concentration of 5∼100 mg/L, the correlation coefficient of the linear equation is greater than 0.997, and the data confidence is high. Furthermore, the content of surfactant in the produced liquid of 7 shale oil Wells in the second member of the Kongdian Formation (Ek 2 ) of Cangdong Sag was determined, and the RSD was less than 5%. The detection method has high accuracy and good reproducibility. In addition, the detection and analysis speed of the interfacial tension method is fast. The operation is simple, and the applicability is strong, which makes up for the shortcomings of chromatography and provides effective support for the detection of surfactant concentration in the produced liquid in the oilfields.