Research On Corrosion Behavior Of 2205 Duplex Stainless Steel In Oilfield Produced Fluid Environment

2205 duplex stainless steel(2205DSS)has excellent mechanical,chemical and technological properties,with high strength,light weight,excellent corrosion resistance and other characteristics,so it has been widely used.However,with the exploitation of oil and gas fields gradually facing the harsh environment,the corrosion of metal materials by formation water in oil and gas fields with high salinity cannot be ignored.Among them,local corrosion of stainless steel is an important factor restricting its application.This type of corrosion is widely valued and studied because of its concealment and destructiveness.This article systematically studied the temperature,CO₂partial pressure,and different heat treatment regimes for 2205 The corrosion behavior of phase stainless steel in simulated oilfield produced fluid and the influence of semiconductor performance.the result shows:(1)At a temperature of 30??150?,the corrosion morphology of2205DSS in the produced fluid of the oil field is pitting corrosion.As the temperature increases,the corrosion products on the surface of the test piece increase,and the area of the corrosion pit becomes larger.The temperature has a significant effect on the composition of the passivation film and the performance of the semiconductor.As the temperature increases,the Cr element content in the passivation film decreases,the Fermi level of the passivation film flat band potential shifts forward,the energy level difference decreases,and the defect density increases Stability decreases and the corrosion rate of 2205 DSS increases.(2)When the partial pressure of CO₂is 0?6 MPa,the corrosion morphology of 2205DSS in the produced fluid of the oil field is pitting corrosion.As the CO₂partial pressure increases,the corrosion products on the surface of the test piece decrease first and then increase,and the area of the erosion pit decreases first and then increases.The corrosion rate of 2205DSS decreases to the lowest when the partial pressure of CO₂is 2 MPa;at 6 MPa,the Cr element in the passivation film decreases significantly,the deposition rate of Fe CO₃decreases,and the corrosion rate reaches the maximum.Under the action of CO₂,the corrosion product film on the electrode surface is dissolved by the acidic medium,and the protection is reduced.The change of CO₂partial pressure has little effect on the semiconductor performance of the passivation film.(3)The corrosion morphology of the 2205DSS with different microstructures obtained in the oilfield produced fluid under the conditions of air cooling,delivery state,water cooling and furnace cooling heat treatment are all pitting corrosion,and the surface of the furnace cooling treatment sample is more likely to appear stable Pitting.The microstructure of the air-cooled and water-cooled heat-treated samples is similar to the supplied state,which is equal proportion of austenite(?)and ferrite(?),and the austenite is still banded.Under furnace cooling conditions,the austenite has the biggest area and the most precipitated phases.The precipitated phases are mainly distributed at the?/?grain boundary and gradually extend into the?phase.The semiconductor performance of the passivation film of 2205DSS of each microstructure is not much different.(4)The 2205DSS with different microstructures have stress corrosion(SCC)sensitivity in the produced fluid of the oil field.The order of SCC sensitivity is as follows:supply state,air cooling,furnace cooling,water cooling.