Changqing Oilfield Corrosion Mechanism And Corrosion Inhibition Technology Research And Application

Produced water caused a long-term corrosion of equipments in Changqing oilfield, corrosion and scaling have seriously affected the normal production and transportation of crude oil, and caused the huge economic losses on the oilfield.The produced water from gathering station of1st oil production factory in Changqing oilfield is of high sulfide, salinity, high levels of bactreia, and content of calcium and magnesium cation is serious. In this thesis, we regarded produced water in device at gathering station as the main research object, the corrosion factors are studied through water quality analysis, the scaling prediction, determination on the number of bacteria, field coupon corrosion test, scanning electron microscopy experiments and analysis of corrosion and scaling products. The result indicates that H2S is the major factor in the impact of produced water corrosion.Wellbore of oil well has a serious corrosion and scale in South-1Zone of the2nd oil production factory in Changqing, as the part of the serious corrosion and scaling well and water allocating station samples for the main research object, the research showed that water sample is the major of H2S corrosion, it accompanied with O2, Cl-and SRB corrosion. In the experiment, we added the corrosion inhibitor, scale inhibitor and bactericide chemical agents to evaluate the anticorrosion and prevent scale to effect of the wellbore. Through the screening of eight kinds of single-agent corrosion inhibitor, we optimized the three kinds of good corrosion inhibition of imidazoline material. As imidazoline to be the main agent, we compounded and optimized the imidazoline. Finally, we got nine kinds of efficient compounding inhibitor, and screened out the best inhibitor and dosing quantity. The results showed that the corrosion inhibition efficiency reached to93%, with NW-04corrosion inhibitor concentration of80mg/L and the corrosion rate reduced from0.0880mm/a to0.0062mm/a. When the adding NW-09concentration was100mg/L, the corrosion inhibition efficiency was94%. Four scale inhibitors were compounded, with30mg/L of scale inhibitor YL-01and YL-02added, the scale inhibition rate was above95%. We compounded four bactericidal, the bacteria of L-1and L-2bactericidal rate was over90%at a dosage of50mg/L. The study found that three water treatment agents have an excellent compatibility, the choice of two dosing formulations have better performance in aiticorrosion, scale inhibition and bactericidal effect.By studying on the process of adding chemicals in South-1area and adding the bactericida to well, after some time for the bactericida taking action, the corrosion inhibitor and scale inhibitor were added, a better corrosion and scale inhibitory properties will be achieved.