Technology Research Of Nanofiltration Dispose Highly Scaled Oily Sewage

Mixing mining,transportation and reinjection processes(MMTRP),have been widely used for produced water in different layers,in Changqing and Yanchang Oilfield,to reduced it's disposal difficulty and to decrease waste,it can help keep formation pressure and boost recovery efficiency,so it had already become the most popular treatment process in these oil field.But ion content in different oilfield or different layer have big difference,especially the scale-forming ions content.Over the years,the research of the scaling and scale prevention in oilfield produced water at home and abroad are focused on inhibiting scale deposition,there also remain some deficiencies in completely eliminate the generate of scaling formation and the preventing aspects.Therefore,How to wipe off scale-forming ions,and reduce corrosion in pipeline and equipmen,is very significant for MMTRP.In this paper,according to the SY/T5523-2006 standard and ion content analysis of produced water,the main scaling type is CaSO4,scaling content analysis were used in MMTRP study.The reinjection feasibility of the mixed produced water from chang-2 layer and chang-6 layer.It turned out that the mixed produced water from chang-2 layer and chang-6 layer,can not reinjection proportionally.When the volume ratio of Chang-2 to Chang-6 was 6:4,the highest mixing proportion was achieved.According to attenuate the simulated water of Chang-2:Chang-6 was 6:4,supersaturation concentration and minimum dispose concentration was confirmed.The results show that it can by removing part of the scale ion of produced water to satisfies the requirement of reinjection.Technology research of nanofiltration dispose highly scaled oily sewage.NF90-4040 model was introduced to produced water after treatment for nanofiltration membrane materials processing,the best operating pressure and inflow requirement has confirmed by research of flocculated produced water of Chang-2 and Chang-6.It turned out that the optimal operating pressure is 1.8 MPa,nanofiltration processing water ?Fe below 5 mg/L,suspended matter less than 60 mg/L,oil below 30 mg/L,the Ca2+?SO42-in chang 2 produced water,respectively,by the process before the 984 mg/L,3637 mg/L reduced to 55 mg/L,56 mg/L,the amount of scale in chang 2: chang 6 = 6:4 by nanofiltration process before the 252 mg/L reduced to less than 50 mg/L,the water recovery can reach 70%.The mixed mining water in Shi baiwan and Chang guanmiao multi-purpose station was studied,afer the nanofiltration dispose in best operating pressure,the effluent quality in Shi baiwan was well and the reinjection standard was met under 5:5.The effluent quality in Chang guanmiao also can meet the reinjection standard under a proportion.