Novel Polymeric Surfactant as Surface Modification Agent for Improved Residual Oil Recovery

A novel approach to address residual oil removal focuses on manipulating the interaction between oil and solid surfaces’ interfacial wettability. This innovation offers a fresh perspective to effectively tackle this issue. By transforming rock surfaces into a highly hydrophilic state, substantial enhancements in oil film detachment efficiency can be achieved. However, conventional anionic surfactants can only transition oil-wet rock surfaces to a mildly hydrophilic state. Therefore, the development of innovative surfactants with advanced interfacial wettability control becomes crucial for effective residual oil management. This study introduces the development of a novel polymeric surfactant, AEVF-S. This distinctiveness of AEVF-S lies in incorporating negatively charged polar groups, significantly boosting its adsorption onto oil-wet rock surfaces. This unique feature enhances hydrophilicity in the exposed head groups, resulting in the surfactant’s exceptional capability to modify surface wettability. AEVF-S’s interaction with submerged oil is particularly noteworthy. This interaction triggers a transformative shift in the surface properties of oil-wet rock, rendering it strongly hydrophilic and oleophobic. The substantial reduction of the contact angle of the oil underwater environment from 147.3° to 99.8° underscores AEVF-S’s superiority over most previously reported surfactants. AEVF-S’s efficacy extends to oil film removal. Under simulated reservoir conditions, it effectively peels off about 97.3% of the oil film in just 6 hours. Additionally, in dynamic core displacement experiments, AEVF-S enhances the oil recovery ratio by an impressive 21.11% compared to simulated water flooding. These results highlight AEVF-S’s potential as a catalyst for efficient residual oil development.