Comprehensive Treatment Of The Sewage Water In Gu-dao Oil Field

When the exploration and development of the oil has been more than 30 years in Gu-dao oil field,its composite water cut has reached 93 percent,and the output of heavy crude oil and tertiary oil recovery is more than 83 percent in the proportion of the total.But the dosage of fresh water is increasing year after year in the oil field.By the end of 2007,daily fluid production rate from oil wells had reached 138,000 tons,and the volume of 127,000 cubic metre among them had been the sewage water that was separated from the oil in the separator unit, and the volume of 105,000 cubic metre water per day was availably injected into formations in the oil field,including the volume of about 94,000 cubic metre fresh water.Moreover,the volume of 19,700 cubic metre per day from the rest of sewage water was ineffectively reinjected into formations as well.Therefore, the injection-production of the sewage water was kept balance basically.When the polymer flooding technique was used widely in Gu-dao oil field,the polymer concentration increased in the produced fluid for oil wells,improving the extent of emulsification for the oil and water,adding the viscosity of produced water,steadying the water-oil interface of displacement front better,increasing the output of thermal heavy crude oil and decreasing the density difference of the oil and water.But it was very difficult for the oil to be separated from the produced water completely.The type of produced fluid containing heavy oil and thermal viscous oil and high polymer was formed for Gu-dao oil field,resulted in the more difficulties of dehydrating of the crude oil and the sewage disposal.Now the sewage disposal technique mostly depend on gravity settling method with additional medicines by the density difference of the oil and water,but conventional medicament have not obviously an effect on the sewage disposal of high polymer cut.Even if increasing medicament concentrations are not able to improve completely the oiliness and suspended matters in the sewage water.At the same time,central gathering station was set up early and oil-water tanks have been unaccelerated aging at large and have been corrupted seriously.The sewage tanks internal component damaged and the pressure filter-tank have been invalidated and are not used any more.The desludging mechanism system can not availably desludge by walling up,with the sludge circulate in the system,affecting great effect in degreasing and getting rid of suspended matters in the sewage water.In this text according to problems that occur between the sewage disposal and water quality requirement for Gu-dao oil field at present,methods which the sewage water resources can be reused are expounded with emphases in terms of the sewage disposal,including dissolved air floatation technique test and its application of scale,RSK multistage separation technique research and its test ,electricity flocculate and air float disposal technique test and its application,the sewage-polymer confection disposal test,tests of water quality requirement of sewage disposal eduction outside,high efficiency three-phase separator technical application and evaporation disposal technique and so on,optimized the sewage water disposal technique adapted to Gu Dao oil field. With these sewage disposal technique's study and its application in the oil field,we begin to find the sewage disposal methods that can settle the type of sewage containing heavy oil and thermal heavy crude oil and high polymer cut.It can supply the technical support of water quality inferiority for the same oil fields,acquiring obvious economic benefit and social benefit.