Study On Material Selection And Protective Measures Of Internal Components Of Walnut Shell Filter

In the oil field,the failure of the internal components of the walnut shell filter caused by corrosion frequently occurs.Based on the investigation and application of the internal components of walnut shell filter at home and abroad,this paper studies the corrosion behavior of Q345R container steel and 2205 duplex stainless steel in simulated oilfield produced water,and provides theoretical basis for protective measures.In this paper,the weight loss method and electrochemical test method were used to study the corrosion behavior of Q345R and 2205 in different environments containing simulated dissolved oxygen in the internal components of walnut shell filter.The weight loss test results of Q345R are as follows.In the CO₂ and CO₂/H₂S environment,the corrosion rate of Q345R increases slightly with temperature.In the H₂S environment,the corrosion rate of Q345R increases with increasing temperature.The electrochemical test results are as follows.In the CO₂/H₂S environment,the electrochemical corrosion tendency of Q345R is relatively small,the electrochemical corrosion resistance is large,and the corrosion resistance is relatively good.In the CO₂ and H₂S environment,the electrochemical corrosion tendency of Q345R is relatively large,the electrochemical corrosion resistance is small,and the corrosion resistance is relatively poor.It can be seen that the corrosion resistance of Q345R is sensitive to the service environment.The results of the study on 2205 are as follows.In the CO₂ environment,as the temperature increases,the corrosion rate of 2205 increases first and then decreases.In the H₂S and CO₂/H₂S environments,the corrosion rate increases with increasing temperature.In the air environment,the sample has a higher self-corrosion potential,that is,the tendency of electrochemical corrosion occurs in this environment.In the CO₂ and H₂S environment,the self-corrosion potential and the self-corrosion current density of the sample are close to each other,indicating that the electrochemical corrosion trends of the two environments are not much different.In the CO₂/H₂S environment,the electrochemical impedance spectroscopy of2205 is fitted with a smaller R_ct,less electrochemical corrosion resistance,and poor corrosion resistance,consistent with the polarization curves and the weight loss corrosion test results.Electrochemical test methods such as constant current polarization,open circuit potential,working potential and polarization curve were used to study the influence of temperature factors on the electrochemical performance of the internal protection of the inner shell of the walnut shell filter,and the surface morphology of the anode after corrosion and The microstructure of the product was observed.The results of the two sets of samples for the Al-Zn-In-Cd and Al-Zn-In-Mg-Ti sacrificial anodes at 30?and 50?are as follows.In the H₂S/CO₂ high salinity oilfield simulated water production environment,the Al-Zn-In-Mg-Ti anode open circuit potential is negative compared with the Al-Zn-In-Cd anode,which has a large corrosion driving force.When a constant current polarization is applied to the Al-Zn-In-Mg-Ti anode,the surface thereof is always in an activated state,and the dissolved state is good.With the increase of temperature,the current efficiency decreases,the open circuit potential and the working potential of the anode show a negative shifting tendency,the solubility performance becomes better,and the anode dissolution morphology is uniformly dissolved from the higher temperature,and is converted into local corrosion dissolution at low temperature.