Experimental Studies On Efficient Treatment Of Produced Liquids From Polymer Flooding Oilfield

There are many problems in the polymer flooding block of Huabei oilfield,such as serious emulsification of crude oil,separation of oil-water interface,dehydration of crude oil and difficult treatment of oily sewage.Therefore,it is urgent to carry out the research on the efficient treatment mode of the produced fluid in the polymer flooding block,so as to ensure the smooth development of the oilfield and meet the requirements of environmental protection.According to the produced fluid of M2 and W31 blocks in Huabei oilfield,the tracking monitoring analysis of crude oil properties and polymer content in the produced fluid was carried out.The injection production conditions of different polymers were designed,and the influence of chemical treatment single agent and formulation system on crude oil demulsification dehydration and sewage treatment was studied by using self made simulated produced liquid.The screening of demulsifiers under different conditions was carried out,and the best demulsifier and flocculating water purifying agent suitable for the treatment of polymer containing produced liquid were selected by using the flocculant complex system.The results show that partially hydrolyzed polyacrylamide is the main factor affecting crude oil dehydration.When the polymer content in the production liquid is lower than 300mg·L^-1,the dehydration effect of crude oil emulsion is not affected;when the polymer content is more than 300 mg·L^-1,the selected demulsifier and flocculant should be used for treatment.The effect of polymer flooding is very serious.When the concentration of the produced liquid is high,the cationic starch and basic aluminum chloride are mixed according to the ratio of3:50.At present,the implementation of polymer flooding is mostly staged construction,and the polymer concentration in the produced fluid also changes with the construction period.According to the monitoring results,the demulsifier added in time can be adjusted to ensure the normal operation of the dewatering system and reduce the treatment cost of the produced liquid.At the same time,it provides a theoretical basis and basis for efficient treatment of produced fluid after large-scale implementation of polymer injection profile control and flooding in the future,and lays a foundation for simplification and optimization of old oilfield.