(83b) In-house Developed Resilient and Sustainable Material for Enhanced Oil Recovery

The increase in demand for oil and decrease in supplies requires enhanced oil recovery (EOR) techniques. The waterflooding method of EOR needs the addition of surface-active agents such as surfactants, thus creating the potential for pollution. The produced fluid is a mixture of oil, water, and surfactant which creates pollution of surface waters and land through the leaks or spills of injected chemicals. Therefore, the development of resilient and sustainable surfactants which can bear the harsh reservoir conditions that is stable at 100^oC reservoir temperature and soluble in 240,000 ppm salinity of formation water is highly desirable.

To address the environmental and stability concerns, the synthesis of new surfactants was conducted using no solvent or green solvents. The chemical structure of the surfactants was designed in a way to incorporate the cleavable bonds such as amide which have shown good biodegradation, less toxicity, and are environmentally benign. The chemical structure was elucidated by NMR (1H and 13C), FTIR, and mass analysis. The heat tolerance and water solubility tests were done by Thermal Gravimetric Analysis (TGA) and aging techniques. The IFT (interfacial tension) and surface tension were measured using the spinning drop method and force tensiometer (Biolin Scientific), respectively. The rheological parameters were identified by the discovery hybrid rheometer (DHR-3).

The in-house developed surfactants showed excellent solubility in low and high salinity brine and TGA experiments revealed degradation temperature over 100^oC which is superior to real oilfield temperature (≥90^oC). In addition, the samples were aged in the oven for 3 months at 90^oC and no decomposition in chemical structure was observed. The cmc, surface tension at cmc, and IFT of the synthesized surfactants were comparable or higher to commercial surfactants.

According to rheological data, the storage modulus was reduced by increasing the amount of surfactant at a lower rate of shear and frequency because of charge screening and polymer interaction.

The in-house developed resilient and sustainable surfactants demonstrated excellent aqueous and heat stabilities and revealed great potential in harsh conditions of carbonate reservoirs.