Destabilization and treatment of produced water-oil emulsions using anionic polyacrylamide with electrolyate of aluminum sulphate and ferrous sulphate

Abstract

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 chemicallybased 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. 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) with the addition of aluminum and ferrous sulphate were used as destabilizing agents for water/oil emulsions, which have been stabilized by surfactant (Tallowamine Acetate). The impact of polyacrylamides with the addition of sulphates in turbidity reduction, COD, viscosity of volume separated water, and zeta potential were explored in this study. The effects of electrolytes such as aluminum sulphates and ferrous sulphate on produced water degree of flocculation in the existence of anionic polyacrylamide were investigated in terms of turbidity reduction and volume of separated water after jar test. Different concentrations of both sulphates added into optimum concentration polyacrylamide selected from jar test were utilized, and at optimum dosage, anionic AN 934 PAM with aluminum sulphate at its optimum concentration was proved as the best way to reduce the residual turbidity compared with other additives mentioned in this research. The results showed that the volume of separated water increased more than 25% compared when only PAMs were used, and the turbidity, viscosity, and COD reduction of separated water improved significantly. Addition of electrolytes such as aluminum sulphate and ferrous sulphate into polyacrylamide are both enhance the destabilization of water in oil emulsion in general compare to when only polyacrylamide used.