Optimization Of Filter Material And Process Parameter Design For Oilfield Polymer Containing Wastewater

With the development of oilfields entering the period of medium and high water cuts,in order to improve oil recovery,major oilfields have begun to adopt polymer flooding technology,which also brings problems in the treatment of polymer-containing wastewater.Filtration is an important link in the treatment of polymer-containing wastewater in oilfields.Polymer-containing wastewater has complex water quality,increased viscosity,increased emulsified oil ratio,and increased salinity.During the filtration process,it is easy to cause a series of problems such as accelerated filter material pollution,and difficulty in backwashing.The performance of filter materials and filtration process parameters are decisive factors in determining the quality of filtered water.Therefore,a filter material suitable for the treatment of polymer-containing wastewater in oilfields is selected,and the process parameters are optimized to improve the filtered water.Water quality and meeting increasingly stringent reinjection water quality indicators are of great significance.The porosity,specific surface area,density,wettability,Zeta electric potential and other physical and chemical properties and surface characteristics of the three filter materials of modified glass sand,emery sand and quartz sand were measured and analyzed in laboratory.Through indoor filtration experiments,the effect of three filter materials on the removal of pollutants in oilfield polymer-containing wastewater was compared.It was found that the filtering effect of modified glass sand on polymer-containing wastewater was slightly worse than that of emery and quartz sand,but the difference was little.This paper established a backwashing regeneration effect evaluation indexηthat takes into account the physical and chemical properties and surface characteristics of the filter material.Through indoor backwashing experimental research,the backwashing coefficientηof modified glass sand,emery sand and quartz sand are successively reduced.It means that the backwash regeneration effect of modified glass sand is significantly better than emery and quartz sand.Therefore,considering the quality of the filtered water and the service life of the filter layer,modified glass sand was preferred as the filter material for the treatment of polymer-containing wastewater in the oil field.For the optimized modified glass sand filter material,the filtration process parameters are optimized through filtration experiments,that is,the particle size of the filter material is 0.5-0.8 mm,the thickness of the filter layer is 1000 mm,the filter speed is 10 m·h^-1,and the filter When the time is 12 h,the filtering effect is the best;the backwashing process parameters are optimized through the backwashing experiment,that is,when the backwashing time is 15 min and the backwashing intensity is 8 L·m^-2·s^-1,the filter layer will be regenerated fullest.