Study On Anticorrosion And Scale Inhibition In The Oilfield Reinjection Water

A research has been made on anticorrosion and scale inhibition in the oilfield reinjection water in order to solve the corrosion and blocking problems in the oilfield reinjection system, taking No.2 Oil Production Plant of Jiangsu Oil Field as representation in this dissertation. Based on the water quality analysis of oilfield reinjection water of YangJia Dam Oilfield,it's confirmed that high salinity,high concentrations of chloride,microorganisms(especially sulfate reducing bacteria) and sulfides were the basic reasons to cause corrosion,fouling and obstruction in reinjection system.Taking oilfield reinjection water of YangJia Dam Oilfield as the research object,a few experiments have been made on evaluation and selection of the corrosion inhibitors,scale inhibitors,sulfur removal agent and bactericide respectively to select the best adding agent and its concentration.The experimental results showed as follows. When the adding concentration of PAPE/HEDP/PAA(mass ratio is 2.5:5:1) was 85mg/L,the average corrosion rate decreased from 0.9720mm/a to 0.0716mm/a with the scale inhibition rate at 98.65%.The adding sulfur removal agent,in which FeCl₃ was 105mg/L together with 10mg/L of flocculant,made the concentration of residual sulfide go down to 1.65mg/L.The Glutaraldehyde/1227 composite bactericide was studied by composite ratio and adding concentration.When the adding concentration of composite bactericide was 25mg/L with the composite ratio at 1:2,bactericidal rate reached to 99.98%at the lowest cost.It's concluded that the three kinds of selected reagents were very effective and have nice compatibility so that the effluent after processing can meet the requirements of anticorrosion and scale inhibition in the oilfield reinjection system.