The Study Of Selecting Water Treatment Technology In Oilfield Of Jizhong Region

In north China,huabei oilfield produced water quality unqualified problem,through the node analysis method,respectively,the oil and water,in addition to the sedimentation tank,produced water filter after the three node sampling analysis,found that the traditional way of produced water treatment is good for removing oil in water,but of SRB and suspended solids removal is not complete,so to update from the water treatment process.In daqing oil field,changqing oilfield and liaohe oilfield produced water treatment and reinjection standard research,in combination with the practical situation of huabei oilfield site,summarizes the produced water treatment process under different reservoir permeability,formed the standard of produced water purification process,namely the extra-low permeability reservoirs using microorganism+ultrafiltration membrane treatment process can be up to 5 mg/L or less oil content,suspended solid content is 1 mg/L or less,suspended particle size 1 microns or less in value;Microorganism+two-stage fine filtration process is used in low permeability reservoir.The process of integrated continuous flow or 3-stage coalesced oil 2 filtration is adopted in the medium permeability reservoir.High permeability reservoir adopts two-stage multi-function filtration process.For a low permeability reservoir in the application of microbial 95 stations produced water treatment combination of ultrafiltration membrane treatment technology,the application of microbial oils and fats processing system can remove large particles,sulfide and free CO₂,in which water oil removal rate was 92.7%,sulfur removal rate was 77.7%,free CO₂ removal rate was 100%,the ultrafiltration membrane treatment system,has a better removal of suspended solids,grease and sulfide,small particles of suspended solids removal rate was 98.5%,water oil removal rate was 99.8%,sulfur removal rate of 100%.Later,finished water quality improvement of produced water treatment station after continuous operation,found that part of the station after discharging produced water treatment can reach the corresponding water quality indicators,but treatment after atmospheric water storage tank to the mouth of the well pipe network gradually formed white sediment,and short time rapid increase,causing water quality exceeds bid.Therefore,it is necessary to analyze the causes of the overshoot after the purification of water quality.Through the filter after the produced water salinity,Ca²⁺,Mg²⁺,sulfide,carbon dioxide,oxygen,and content such as bicarbonate quantitative analysis comparison,get 10000 mg/l or higher salinity content of calcium and magnesium ions or 100 mg/l color is white,the reasons for the increase in the content of suspended solids.Therefore,put forward the electrochemical catalytic oxidation-molecular sieve adsorption-selective resin exchange process,through the indoor experiment analysis,it is concluded that 1)electrochemical catalytic oxidation system,the removal rate of Ca²⁺,Mg²⁺,Ba²⁺and scale cations was35.5?50.8%;2)NaOH:100mg/L was injected into the sedimentation tank after electrochemical catalytic oxidation system;Na₂CO₃:350mg/L can cause chemical deposition reaction of Ca²⁺,Mg²⁺and Ba²⁺cationic ions in the water,and further reduce the removal of Ca²⁺,Mg²⁺,Ba²⁺and scale cationic removal rate of 85.9?87.0%.3)the activated zeolite in the separation sieve adsorption system is mainly aimed at the Ca²⁺ion with certain adsorption removal effect,which can remove the Ca²⁺ion removal amount of 16.8?20mg/L;4)the activated carbon in the separation sieve adsorption system has a good function of removing oil and suspended solids in water,which can control the oil in the water as 0.5?0.6mg/L;The removal rate was97.7?98.1%,and the suspension was controlled at 1.25?1.26 mg/L.The removal rate is96.6?96.7%,which will provide water quality assurance for the intake of the ion-exchange system.5)D751 type macroporous polystyrene in ion exchange system is the amino iminodiacetic acid type?[-N-?CH₂COOH?₂]?chelate selective cation exchange resin,selective exchange remove Ca²⁺,Mg²⁺,Ba²⁺into scale cation function,removal rate of 100%.