A Study On Corrosion Behavior And Material Selection Of Western Sulfur-bearing Oil And Gas Gathering And Transportation Pipeline

In recent years,the development and utilization of sulfur-containing oil and gas fields in the western stage of rapid growth,but the harsh environmental conditions and high-temperature,high-pressure,high operating conditions of chloride ion,so that during the operation of oil and gas gathering system,there are various corrosion problem.Determine the actual operating conditions of the western sulfur-bearing oil and gas fields through investigation,study the corrosion behavior of the three materials of L245NS?316L,and 2205 duplex stainless steel under these operating conditions,as well as the influence of SRB on the corrosion behavior of the three materials,and screen suitable Materials for gathering and transportation systems in western sulfur-bearing oil and gas fields,thereby improving production efficiency.First,the article conducts physical and chemical tests on these three materials,analyzes their physical and chemical properties,and then conducts corrosion tests and electrochemical tests,supplemented by scanning electron microscopy(SEM),energy spectrum analysis(EDS)and ultra-depth pit depth measurement techniques to study Corrosion resistance of the three materials.The test results show that the anti-HIC and anti-SSC properties of L245NS and the anti-SSC and anti-SCC properties of 316L and 2205 meet the standard requirements.The test results of high temperature autoclave immersion show that the average corrosion rate of L245NS is the largest(0.3111mm/a),which belongs to extremely serious corrosion;the average corrosion rate of 316L and 2205 is not much different,and both belong to mild corrosion.There are a lot of pitting pits on the surface of L245NS sample,the depth of pitting pits is up to 69.9?m,the corrosion resistance is the worst;the surface of 316L sample only appears a few pitting pits,the maximum pitting pit depth is only 10.0?m;2205 No pitting pits were found on the surface of the sample.This is because 316L and 2205 are added with elements such as Cr,Mo,Ni,and the corrosion resistance is improved.However,the content of Cr and Mo in 2205 is higher than that of 316L,and 2205 has better corrosion resistance.The results of the immersion test in the produced water simulation solution of the western sulfur-bearing oil and gas fields containing SRB show that the average corrosion rate of L245NS is the largest(0.0109 mm/a)after 10 days of immersion,and the average corrosion rate decreases with the extension of the immersion time,but both It belongs to mild corrosion;the average corrosion rate of 316L first increases and then decreases.The average corrosion rate after immersion for 20 days is the largest(0.0013 mm/a),which belongs to mild corrosion;the average corrosion rate of 2205 has been increasing,reaching the maximum(0.0023 mm/a)at 30days,all of which are mild corrosion.Overall,the average corrosion rate of L245NS is the largest,followed by 2205,and the average corrosion rate of 316L is the smallest,but they are all mildly corroded.Electrochemical test results show that the self-corrosion potential E_ccor of L245NS is larger than that of 2205 and 316L,and the self-corrosion potential of 2205 duplex stainless steel is the smallest,which indicates that under the operating conditions of the western sulfur oil fields,L245NS has the greatest corrosion tendency,and 2205 has the least corrosion tendency.The presence of Cr₂O₃ and Cr O₃ in the corrosion products of 2205 duplex stainless steel makes the internal structure of the film more stable and better protects the matrix.Therefore,2205 duplex stainless steel has the strongest corrosion resistance.Under the actual operating conditions of the western sulfur-bearing oil and gas fields,2205showed the best uniform corrosion resistance and localized corrosion resistance;in the immersion test in the produced water simulation solution of the western sulfur-bearing oil and gas fields containing SRB,2205 duplex stainless steel shows the best corrosion resistance;on the whole,2205 duplex stainless steel has the best corrosion resistance and is the best material for gathering pipelines in western sulfur-bearing oil and gas fields.