The Investigation Of Phosphonic Scale Inhibitor Used Favourable In Baolang Oilfield

Ca²⁺and Mg²⁺ion are concentrated on formation water in Baolang oilfield.TheCO32-icon concentration rises because of Formation pressure drop.It leads to scaleand corrosion in oil well, the production pipeline and water injection formation whichaffect the production of oilfield.The research investigates the phosphonic scale inhibitor used favourable inBaolang oilfield to solve the problems including corrosion,short period of scaleinhibitor in the scale control technique application process.This research aims atdeveloping combined techniques to handle the scale and corrosion in oil produce withhigh-efficiency and low concentration.Scale inhibitor works by means of shielding or wrapping the scale ion such asCa²⁺,Mg²⁺and Ba²⁺to reduce its concentration or make concentration of ion under thelowest concentration of scale.The produce of Baolang oilfield is affected by scale caused by the rise ofconcentration of CO32-,Ca²⁺,Mg²⁺and Ba²⁺icon.The scale inhibitor application inBaobei block,Baozhong block and Benbutu Block in2004is effective,but the scaleinhibitor causes corrosion in produce equipment.Besides,the scale inhibitor applicationcosts high because of short period.The result shows that the scaling type of Baolang oilfield is CaCO3based on thestudy,so phosphonic acid such as BHMTPMPA,HEDP,PBTC,DTPMP,EDTMPS andATMP is used in experiment because of its high efficiency to calcium.Scale inhibitorsand corrosion inhibitors have been selected based on laboratory experiments, includingscale inhibition efficiency,compatible tests,minimum inhibitor concentrationexperiments and corrosion inhibitor efficiency experiments.The previous scaleinhibition has high inhibition rate.When the inhibition rate approach95%,the concentration of scale inhibitor is9mg/L,and the corrosion rate is above0.67mm/a,andthe scale deposition rate is above2.8mg/（cm2month）.The phosphonic scale controlsystems in the three block selected based on experiments are better than the previousscale inhibitor.On the same condition of inhibition rate approaching95%,theconcentration of scale inhibitor, the corrosion rate and the scale deposition rate of thephosphonic scale control system are lower than the previous scale inhibitor.Finally thephosphonic scale inhibitors used favourate in Baolang oilfield based on laboratoryexperiments are:the Baobei block scale inhibitor consists of DT and HE withconcentration ratio for4:1,6mg/L,and EDTMPS with concentration for70mg/L;theBaozhong block scale inhibitor consists of BH and ED with concentration ratio for1:1,6mg/L,and EDTMPS with concentration for90mg/L;the Benbutu block scaleinhibitor consists of PB with concentration ratio for8mg/L,and EDTMPS withconcentration for90mg/L.The results of this investigation can reduce the effect onoilfield produce caused by scale and corrosion,the cost of scale control techniqueapplication,and maintenance work in the production process.