(531d) Destabilization and Treatment of Produced Oil-Water Emulsions from EOR Application Using Polyacrylamides

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 sort of organic and inorganic admixture. The discharging of produced water contaminates not only the water, both surface and underground, but also the soil. 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 (Talowamine Acetate).

The impact of the surface charge form, the density of polyacrylamides in turbidity reduction , zeta potential, COD, viscosity of separated water were explored in this study. Different anionic polyacrylamide of different surface charge density and molecular weight were evaluated. Different anionic polyacrylamides were utilized, and at optimum dosage, anionic AN94 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 effects of electrolytes such as aluminum sulphates on produced water degree of flocculation in the existence of PAM were also investigated in terms of turbidity reduction and volume of separated water after jar test. The results showed that the volume of separated water increased more than 25% compared when only PAMs were used, and the turbidity of separated water improved significantly.