A Study On Emulsified Crude Oil Properties Of Anionic/Non-ionic Surfactants

In the EOR process, flooding by using surfactants has become an effective method forenhancing oil recovery. At present, there have two types of surfactants which used frequently,one is anionic surfactants, and the other is non-ionic surfactants. When we use anionicsurfactants alone, there always have a weak point like poor salt tolerance. But the systembetween the two compounds shows better characteristics than the single surfactant, and ableto adapt to the different oil-water conditions. So it has a great promise in the oil extractionprocess.This article use a type of non-ionic surfactants named MOA fatty alcohol ethoxylates andthe anionic surfactants named alkyl benzene sulfonate which mix together according tocertain proportion, and make up the ASP flooding system. As the emulsification of surfactantand crude oil is explanation to flooding mechanism. So we determine the interfacial tension ofthe system and analysis of water rate of the emulsion, to study the relationship between them.Then determine the type and viscosity of the emulsion at the same time.At first, we use three kinds of fatty alcohol ethoxylates named MOA-4, MOA-7, MOA-9mixed with heavy alkyl benzene sulfonate according to the quality ratio of1:9, and study thesurfactants of the flooding systems. And prepare the emulsions of three complex alkalinesurfactant systems and crude oil from NO.2Daqing Oil Production Plant according to theratio of1:1, to study the stability of the emulsion, at the same time determine the droplet sizeand viscosity of the emulsion by using Microscopy and the Brinell rotation viscosity meter.The result shows that when the mass concentration of alkali is0.6%-0.8%, the surfactantconcentration was0.05%-0.2%range, comparing with other surfactants, the interfacialtension of MOA-4complex surfactant orders of magnitude in the10-3. The lowest interfacialtension of three complex surfactant systems within2h can reach2.53×10^-3mN/m, but thecorresponding emulsion analysis of water was9%, it isn’t the lowest value. Therefore showthat there is no obvious relationship between the interfacial tension and emulsion stability.