Study On The Influence Of Oil Displacement Agents On The Stability Of Crude Oil Emulsion

Chemical flooding technology has been widely applied in Daqing Oilfield to enhance oil recovery. With the application of various combined flooding, the stability of the oil/water emulsion in produced oily water of Oilfield significantly increased. It's very important to investigate the influence of the displacement agents to stability of crude oil emulsion, because it can not only give theoretical concstruction to the development of demulsifiers, but also improve economic benefit of combination flooding.Three typical kinds of produced liquid which involve foam combined flooding, binary combined flooding and polymer flooding in Shengli oilfield has been studied in this paper. Stabilization of crude oil emulsion in combination flooding was investigated through phase splitting measurement.The effect of oil displacement agents on crude oil emulsion stability was characterized through oil/water interfacial tension, interfacial shear visicosity, Zeta potential and so on. The effect of single oil displacement agents and double oil displacement agents on stability of crude oil emulsion has been also investigated. The effect of oil displacements agents on stability of crude oil emulsion has been investigated in different experimental conditions. These experimental conditions include temperature, demulsifier concentration, emulsify intensity etc. The selection of demulsifiers and in-situ application of demulsifiers has been studied in Chengdong production mill and in Gudong production mill respectively.The results show that, single surfacant and foam can lead to oil/water serious emulsification, decrease the interfacial tension and dehydration rate, increace the interfacial shear visicosity and stability of crude oil. Single polymer can increase oil/water interfacial shear visicosity, decrease dehydration rate, influence on water color greatly. Surfactant and polymer had a great influence on dehydration rate, water color and stability of crude oil in the produced liquid. There is a synerfism among surfactant and polymer. Temperature, emulsification intensity and demulsifiers had great influence on stability of crude oil. There is preferable effect on the selection and in-situ application of demulsifiers.