Study On Inhibiting Corrosion And Scale Controlling In Oilfield Produced Water

In this dissertation,the present situation of development and prospects of water treatment chemicals were studied on the base of having consulted lots of documents.It showed that the close relation between development of technology of water treatment and environment protection.Inhibiting corrosion and scale performance of several chemicals were studied respectively in the surrounding of oilfield produced water from Baikouquan of Karamay.So the study was divided into two parts including the inhibiting corrosion and scale controlling.In the first part,polarization curve technique and static weight-loss method were used to study influence factors such as LSI(x1)、MoO42(-x2)、Ni2+(x3)and Co2+(x4)on corrosion for A3 carbon steel in standard prepared water environment.Relational regression Y=15.0937-0.02994X1X2-1.44018X12-7.20935X1+0.09344X2+1.842835X4 between inhibition efficiency and effect parameters were derived based on uniform design and regression analysis,optimum experiment dosages and corrosion inhibition ratio were determined according to program solving method.The result was checked in both standard prepared water and oilfield produced water.Qualitative and semi quantitative analysis were used not only to predict a possible mechanism of protective film but also to infer film type on carbon steel by SEM technique and EDS spectrum method.Relationship between parameter changes and corrosion inhibition were studied by testing the value of pH ,specific conductance,the oxygen,the turbidity,the concentration of molybdate in sample solution.It was shown that parameter result tended to keep constant after compact protective film formed on the surface of carbon steel.In the second part,scale inhibition among HEDP,sodium humate and sodium hexametaphosphorate were arranged with orthogonal design in the running water.The influence extent orders were as following: HEDP>sodium hexametaphosphorate>sodium humate.Then uniform design was used to derive relational regression r=-47.29-0.173x12 -0.4752x1x3+10.05x1-0.7008x2+6.842x3 between HEDP(x1),sodium humate(x2)and sodium tripolyphosphate(x3).The maximum scale control ratio which according with test value was r=89.99% through program solving method.In the end,a possible scale control mechanism for scale inhibitor was put forward by SEM on the surface of scale powder.