The Experimental Study Of Electrostatic Dehydration Of SAGD Produced Liquid From Fengcheng Oilfield

The extra-heavy oil is rich in suspended solids,colloid and asphaltene,and ?space steric? effect is significant due to the existence of small solid particles,making the deep dehydration of produced liquid quite difficult.Although high-voltage pulsed electric field can significantly improve the efficiency of demulsification,it has not yet been applied to deep dehydration of extra-heavy oil.This paper mainly adopts high-voltage pulse technology to study the effect of impurity composition on electrostatic dehydration of extra-heavy oil,which provides reference for the effluence of impurities and the development of high-performance compact electrostatic coalescer.At first,we systematically investigate the effect of electric field parameters(voltage amplitude,duty ratio and frequency)and operating parameters(temperature and dewatering time)on efficiency of electrostatic dehydration.And the experimental results show that with the increase of electric field parameters,dehydration efficiency all increases before decreasing gradually.Dehydration efficiency can reach its maximum value of 97.81% when voltage amplitude,frequency and duty ratio are all optimal.In addition,dehydration efficiency can also be improved by increasing temperature and dewatering time.However,the energy consumption will increase dramatically when the values are too big.Secondly,dimethyl silicone oil is used as the continuous phase to explore the effect of impurity components on dewatering efficiency of simulated oil emulsion.The experimental results show that suitable inorganic salt concentration is beneficial to the improvement of efficiency of electrostatic demulsification,but if the concentration was too high,excessive polarization and electric dispersion could occur.The higher the ion level,the stronger the momentum of impact on interfacial film,the bigger the demulsification efficiency.With the addition of surfactants,the ability of springing back and fusion is weakened,thus demulsification efficiency is lower.When surfactant concentration is above critical micelle concentration(CMC),demulsification efficiency tends to be stable.Compared with oil-soluble surfactant,the resistance of water-soluble surfactant on emulsion is much smaller,which makes demulsification efficiency higher.Demulsification efficiency is improved dramatically with pH value.The electrostatic coalescence effect is far from ideal due to strong activity of surfactant when pH is 10.3.Small solid particle can be quickly adsorbed to oil-water interface,thus improving the stability of emulsion,making dehydration efficiency decline.This paper lays foundation for efficient electrostatic demulsification of SAGD produced liquid.