Surfactant and polymer flooding technology can greatly enhance the oil recovery through the expansion of sweeping and displacing efficiency. The recovered oil from surfactant and polymer flooding emulsifies the residual chemical, which makes the separation of water from oil quite difficult, yet the impact of the enhanced oil recovery (EOR) chemicals on the produced water cycle is generally neglected in chemically-based EOR studies. This includes compatibility of EOR chemicals with the additives used to pre-treat the injected water or change reservoir wettability and result in producing oil/water emulsion after EOR breakthrough.
The largest waste produced in oil and gas industries is believed to be the produced water, as it contains different particles of organic and inorganic admixture. There are a number of treatment methods available for produced water. To separate water from oil in a much efficient manner and to reach the emission standard, a new class of water soluble polymer of polyacrylamides (PAMs) was used as destabilizing agents for water-oil emulsions, which have been stabilized by surfactant.
The impact of the surface charge form, the density of polyacrylamides in turbidity reduction, zeta potential, COD, FTIR, viscosity and volume of separated water were explored in this study. Different anionic polyacrylamide of different surface charge density were evaluated. Different anionic polyacrylamides were utilized, and at optimum dosage, anionic AN 934 PAM at its optimum concentration was proved as the best way to reduce the residual turbidity compared with other PAMs mentioned in this research. The effect of the different salinity (salt content: 200,000 ppm brine and 57,000 gulf seawater) of produced water will be evaluated using different PAM with different charge density as optimization. The results showed that the W/O emulsion stability related with its salinity, while the optimum concentration of demulsifier are same at both high and low salinity.