| DP-4 block of FB oilfield is the main development block of FB oilfield,with permeability variation coefficient of 0.8 and viscosity of underground crude oil between55-125 mpa.s.this block belongs to class II reservoir and has entered the stage of high water cut development.During the exploitation process,a large amount of wastewater such as oil and solid suspended matter will be produced.If the sewage of these oilfields cannot be treated in time,it will be directly reinjection Utilization will cause serious pollution and will have adverse effect on the subsequent development and utilization of oil fields.In order to improve the recovery of crude oil,polymer flooding technology is used in FB oilfield and good results are obtained.However,with the deepening of polymer flooding,the oil content,solid suspended matter content,polymer and other impurities in the wastewater of polymer flooding gradually increase,and the emulsification is serious,and the sewage treatment is difficult.It is urgent to find a low cost and good effect treatment technology for the treatment of the wastewater containing polymer,so as to reduce the oil and suspended matter in the sewage,so as to meet the wastewater reinjection standard,and prevent adverse effects on the subsequent development of the oilfield,At the same time,it also avoids the problems of water resource waste and environmental pollution.In this paper,based on the actual wastewater produced in DP-4 block of FB oilfield,the indoor experimental study of polymer containing wastewater treatment was carried out.Firstly,the water quality analysis and emulsification degree determination of the polymer containing sewage in the sewage treatment station of the block are carried out.By comparing the polymer containing sewage with other sewage quality,the basic parameters of the polymer containing sewage quality in the block are mastered.The sewage in this block is discharged into the settlement device for settlement treatment,and the experimental effect of sewage settlement in this block under various settlement conditions is studied,and then the experimental study on the mixed settlement of polymer containing sewage and advanced treatment sewage is carried out.The different sewage in this block is mixed and then flows into the filtration device for filtration treatment,and the experimental effect of mixed sewage sedimentation under various filtration conditions is studied.The polymer solution dilution experiment was carried out by using different sewage in the block,and the solution viscosity was measured and compared.Long cores with different permeability combinations are used to carry out polymer flooding experiments,and the displacement effects of different polymer solutions are compared.The results show that the best mixing ratio of polymer containing wastewater and advanced treatment wastewater is 4:1;The best settling time of mixed wastewater is 8h;The best filtration rate of mixed sewage is 8m / h ～ 9m / h,and the best ratio of filtration media is ratio 2.The viscosity loss rate of polymer solution diluted by mixed wastewater is high and its stability is poor;The EOR of polymer solution diluted by mixed wastewater is 0.71% lower than that of polymer containing wastewater,so it is feasible to mix polymer containing wastewater with advanced treatment wastewater. |
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