Enhancing Oil Recovery by Low Concentration of Alkylaryl Sulfonate Surfactant without Ultralow Interfacial Tension

Abstract

Surfactant flooding plays a critical role in chemically enhanced oil recovery over the last half century, with the widely accepted mechanism of ultralow interfacial tension (IFT) by forming middle-phase microemulsions with high concentration of a lead surfactant and a cosurfactant. However, it is found practically from field trials that high oil recovery efficiency can be obtained from low concentration surfactant flooding without forming microemulsions, and the principle behind has not been clearly unraveled yet. Here the solubilization of paraffin oil by the micelles formed with a commercial enhanced oil recovery surfactant, raw naphthenic arylsulfonates (NAS), was investigated using ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). It is found that paraffin oil can be well solubilized inside the NAS micelles, and mainly localized in the hydrophobic core of the micelles. The solubilization capacity of NAS micelles increases with increasing its concentration, and the size of micelles increases, but morphology of the micelles remains spherical with increasing the amount of paraffin oil, along with an appearance transition from transparent to opaque until the maximum solubilization capacity is reached. Core flooding results with crude oil indicate that in the presence of 0.24 wt.% polymer, addition of 0.1, 0.2, 0.5, and 1.0 wt.% NAS can get oil recovery factor of 24.1%, 27.0%, 30.5%, and 38.3%, which increases linearly with increasing NAS concentration though with the interfacial tension values only in the magnitude of 10 −2 mN m −1 level. These findings prove preliminarily micellar solubilization can help increasing oil recovery efficiency even without ultralow IFT.

New advances in surfactant EOR mechanism: micellar solubilization and <italic>in-situ</italic> emulsification

“…根据此前的报道 [47,48] , IFT 物溶液被用作后置段塞. 所有实验温度均为40℃ [43] (网络版 彩图) 表 1 NAS-KYPAM体系的岩心驱替结果 [43] Table 1 Core flooding results of NAS-KYPAM flooding [43] 层的荧光图像. λ ex = 420~485 nm, 比例尺为500 μm [49] (网络版 彩图)…”

Surfactants Enhanced Heavy Oil–Solid Separation from Carbonate Asphalt Rocks-Experiment and Molecular Dynamic Simulation

“…He et al [ 41 ] used the nonionic surfactant/nanoparticle composite system to enhanced oil recovery, the oil recovery rate increased by 16.8%. Zhan et al [ 42 ] used the low concentration of alkylaryl sulfonate surfactant to enhanced oil recovery and the main mechanism was the solubilization of surfactants. Machale et al [ 43 ] studied the natural surfactant effect on oil/water interfacial tension, and the surfactant was used to enhanced oil recovery.…”

Special Issue Honoring Professor Milton Rosen

“…Surfactant interaction parameters were determined for surfactant mixtures and related to Winsor microemulsion formation for drug delivery applications. The role of micelle solubilization on enhanced oil recovery was examined by Feng et al (Zhan et al, 2021). using naphthalenic arylsulfonates (NAS).…”