表面技术2025，Vol.54Issue(12)：124-133,10.DOI:10.16490/j.cnki.issn.1001-3660.2025.12.011
13Cr马氏体不锈钢在氯化钠和甲酸钾环境中的腐蚀差异性研究
Corrosion Difference of 13Cr Martensitic Stainless Steel in Sodium Chloride and Potassium Formate Environment
摘要
Abstract
With the development of deep and ultra-deep wells in oil and gas fields,the high temperature and high pressure environment puts forward higher requirements for the performance of completion fluid.Formate completion fluid is more popular in oilfield application due to its advantages of high density,good thermal stability,strong anti-pollution and low corrosion.13Cr martensitic stainless steel is the main material of high CO2 well casing.When the failure of downhole packer leads to the invasion of CO2 into the annulus of oil casing,the coexistence of weak alkaline environment of potassium formate completion fluid and CO2 may cause complex corrosion problems of 13Cr materials.There is still a lack of systematic understanding of the dissolution characteristics of potassium formate under the synergistic action of CO2,the stability of passivation film and its corrosion behavior to metals.It is necessary to further explore its corrosion mechanism to optimize the safety design of deep well completion. 13Cr samples(50 mm×10 mm×3 mm)were polished(240#-1200# sandpaper),cleaned,dried,and weighed(0.1 mg accuracy).After N2 deaeration(2 h)in a high-temperature/high-pressure autoclave,corrosion tests were conducted at 60 ℃/90 ℃under 10 MPa CO2(static,5 days).After the test,samples were reweighed to calculate uniform corrosion rates.Pitting depth and rates were measured via laser confocal microscopy.Surface morphology and corrosion products were analyzed through SEM and XPS. In-situ electrochemical tests,including polarization curves and electrochemical impedance spectroscopy(EIS),were performed to analyze the microscopic corrosion behavior of 13Cr steel in different corrosive environments under high temperature and high pressure conditions.In addition,a Pt counter electrode and an Ag/AgCl reference electrode were adopted in the tests.Samples(φ15 mm×3 mm)were polarized in NaCl solution from-300 mV to+300 mV(vs.ocp)and in potassium formate solution from-300 mV to+1 300 mV(vs.ocp),with a scan rate of 0.2 mV/s.For EIS measurements,an AC signal amplitude of 10 mV and a frequency range of 10 mHz to 100 kHz were applied.Data from the EIS spectra were analyzed with ZSimpWin. In the comparison of potassium formate and sodium chloride environment,13Cr showed more negative self-corrosion potential and larger self-corrosion current density in the potassium formate system,and the anodic polarization curve showed a significant passivation zone,which was directly related to the reaction of formate(HCOO-)with dissolved Cr element to form Cr(HCOO)3 surface sediment.EIS analysis showed that the AC impedance value in the potassium formate environment was significantly lower than that in the sodium chloride environment,and the protective passivation film of Cr2O3/Cr(OH)3 on the surface was completely destroyed.The formation of Cr(HCOO)3 not only hinders the formation of Cr(OH)3 and Cr2O3 passivation film,but also accelerates the dissolution of anode metal.At the same time,the H2CO3 generated by CO2 dissolves in water,enhancing the cathodic hydrogen evolution reaction,and the synergistic effect of the two leads to a significant increase in the corrosion rate of 13Cr in the presence of CO2-potassium formate.关键词
13Cr马氏体不锈钢/甲酸钾完井液/氯化钠完井液/CO2腐蚀Key words
13Cr martensitic stainless steel/potassium formate completion fluid/sodium chloride completion fluid/CO2 corrosion分类
矿业与冶金引用本文复制引用
陈浩东,魏安超,肖平,李祝军,娄益伟,于延钊,张鑫鑫,刘佳乐..13Cr马氏体不锈钢在氯化钠和甲酸钾环境中的腐蚀差异性研究[J].表面技术,2025,54(12):124-133,10.基金项目
中海油集团公司"十四五"重大科技项目(KJGG2021-0800)Major Science and Technology Projects of CNOOC Group During the 14th Five-Year Plan Period(KJGG2021-0800) （KJGG2021-0800）
