(586h) A Comprehensive Study of Surfactant-Polymer Formulations for Oilfield Applications

The oilfield industry is making efforts to enhance the production of running oil wells to meet the global energy demand. The chemical-enhanced oil recovery (cEOR) method plays a crucial role, offering capable ways for enhancing oil recovery. However, conventional chemicals used for cEOR encounter stability issues when applied in harsh reservoir conditions such as high salinity and high temperature.

This work explores the synthesis and application of betaine-based polyoxyethylene surfactants for chemical-enhanced oil recovery (cEOR) under harsh conditions. The surfactants were designed to address high temperatures and high salinity conditions in reservoirs. The structures of the synthesized surfactants were identified by nuclear magnetic resonance, Fourier transform infrared, and Thermogravimetric analysis (TGA) followed by surface analysis. The surfactants were then combined with the commercial polymer with different mixing ratios to identify the best ratio for the rheological parameter identification using the discovery hybrid rheometer (DHR-3).

TGA data displayed that the synthesized surfactants showed excellent thermal stability, exhibiting outstanding resistance to temperatures up to 280°C. Experimental findings including critical micelle concentration and interfacial tension have shown that the synthesized surfactants are fairly stable and efficient in reducing surface tension between oil and water. In addition, the surfactants were found to be compatible with the polymer and no precipitation or phase separation was detected in surfactant-polymer formulation. The rheological results showed that the storage modulus was dropped while increasing the amount of surfactant at lower shear and frequency due to charge screening and chemical interaction.

The current work highlights an important advancement in cEOR technology, offering a promising route to enhance oil recovery, especially in harsh oilfield conditions.