Technology Research Of Heavy Oil Heavy Oil Wastewater Recycling For Boiler In Gudao No.2porduced Water Treatment Station

This article specified the process flow and design parameters,and made an analysis discussion about the process of oil removal,hardness removal and desalination based on the site experiment research aboutheavy oil produced water recycling for boiler in Gudao oil field.The result indicate that using bio-oil removal process combining with traditional flocculation,sediment,filtration,hardness removal and desalination process could make the treatedwater meet the requirement for boiler use.So this technology could take much economic and environment benefit for recycling of produce water in oil field.Presently,Shengli oil field has been developed into the middle-late stage,general water percentage increased continuously.Meanwhile,water injection,thermal recovery,polymer injection etc.such methods made the quantity of produced water increased continuously.However,no injection necessary for some blocks and fresh water used for some blocks made the unbalance of producing and consumption more seriously,which made much redundant produced water.The residual was recharge to layer,that made the pressure become higher,so new approach for the resolutionof residual water is urgently.Oppositely,the boiler is always consumingfresh water,such as Gudao 1#and 9#steam injection station has 5 boilers,and the consumption will be 6000m³/d in the near future.Therefore,recycling the residual produced water in Gudao No.2 station for the two steam stationsuse will save much fresh water even resolve the residual water.1.Process Flow and IntroductionThe characteristic of the produced water in Gudao No.2 station is:Oil 153.6mg/L,Total Hardness 294.1mg/L,Total Iron 1.38mg/L.The research made the produced water as object,and the design capacity was defined as 800m³/d.the process flow was divided as biology oil-removal and suspended solid removal unit(1^ststage floatation,2^ndstage electrocatalytic floatation,3^rd stage electrocatalytic floatation),biology suspended solid removal unit(1^st stage shell filtration,2^ndstage sand filtration),ion exchange unit(1^ststage ion exchange hardness removal,2^nd stage ion exchange hardness removal),electroosmosis unit（desalination）.1)Bio-oil removal andSS removal unit:firstly,the produced water in Gudao No.2station was lifted into 1^ststage electric floatation device,accompanying with the injection of coagulant and flocculant,the most part of the oil and SS was removed.Next the water flowed into the 2^nd stage electric floatation device forfurther removal of the oil,SS and iron under the condition of agent injection.Finally,water entered into the 3^rd stage electric floatation device to make sure the water outlet could meet the requirement for filtration.2)Bio-SS removal unit:the produced water treated by floatation was lifted into the1^ststage filtration and 2^nd stage sand filtration to further remove the SS in water.3)Ion exchange unit:the produced water treated by filtration flowed into the double stage ion exchangedevice,in order to decrease the positive ion concentration to the PPB class,mainly for hard ion as Ca²⁺Mg²⁺etc.4)electrodialysis unit:access to the electrodialysis device for desalting water,desalted water after heat exchanger heat into steam injection boiler with water treatment systems.The technology described in this article has been put into use in Gudao oil field,which realized the recycle of produced water and the treated water could meet the requirement for boiler use.