A Study In Technical Limits Of Polymer-contained Water Sedimentation And Filtration

The sedimentation and filtration effect of produced water with different polymer concentration is studied in the lab,which is based on the treatment technic of produced water in water flooding and polymer flooding in Daqing Xingbei oilfield,so as to make out the polymer concentration limit of produced water for further treatment.The viscosity of produced water with different polymer concentration is measured by Brookfield viscometer,in which the relationship between concentration and viscosity is obtained.The viscosity of polymer-contained water increased with its concentration.To say exactly,the viscosity is 1.23 to 3.8mPa·s with the concentration 100 to 800mg/L.Also,the oil droplet size distribution in produced water with different polymer concentration is measured by laser particle size analyzer,in which it is concluded that the higher polymer concentration in it the bigger oil droplet size in it.The mid-size of oil droplet is 4.53 to 50.05?m with the concentration 100 to 800mg/L.Based on the studies above,sedimentation effect of produced water with 6 kinds of polymer concentration is studied with different time both in the first and the second sedimentation,using the lab sedimentation device,by analyzing the variety of oil content,suspended solid content and viscosity of the liquid in Entrancech and exit of the sedimentation device.And then,the study in flocculant effect on the sedimentation indicates that it is helpful to add flocculant into sedimentation liquid.The best dosage of flocculant to add is 50mg/L when the polymer concentration is no more than 300mg/L,and it is 100mg/L when the polymer concentration is between 300mg/L and 500mg/L.So it gives the technical limits of water sedimentation with different polymer concentration On the basis of above comprehensive analysis.Through analysis of linear regression fitting time and again,the Stocks' globule sedimentation theory formula is revised to make the rising rate of oil droplet count enable,so as to set up the relationship among oil content and polymer concentration and sedimentation time.Organic glass visualized indoor filtration experiment device was established.Five concentration sewage was obtained by mixing produced water in water flooding and polymer flooding,which was used to carry out 5 types of rate and 4 types of gradation in two-stage filtration experiment.By measuring oil content,suspended solid content and viscosity of the liquid before filtration and after the exit of the filtration experiment device,it is concluded that filtration effect of produced water is better under suitable filtration rate and gradation.That is to say,oil content and suspended solid content reach to injected water standard,with both their concentrations no more than 5mg/L.It gives economic and suitable filtration rate and gradation through indoor filtration experiment and theory analysis,which gives the technical limits of water filtration with different polymer concentration.The study will provide theory evidence,which has better guiding significance in the field treatment of polymer-contained water.