高酸性环境下复合管焊缝耐蚀性能研究.docVIP

  高酸性环境下复合管焊缝耐蚀性能研究# 曾德智1,2，黄黎明2，谷坛2，袁曦2，霍绍全2，施太和1* （1. 油气藏地质及开发工程国家重点实验室（西南石油大学），成都 610500； 5 10 15 20 25 30 35 40 45 2. 中石油西南油气田分公司，成都 610213） 摘要：四川罗家寨气田群 H2S 含量约 17%，CO2 含量约 10％，气田水中氯离子含量约 20g/L， 地面管线压力约 9MPa。地面管线面临严峻的腐蚀挑战，此时采用双金属复合管是一种既可 靠又较为经济的防腐措施。而双金属复合管的焊接涉及异种钢的焊接，异种金属焊接比较困 难，且焊接过程中外层碳钢会稀释耐蚀合金，造成耐蚀性能降低。因此，对双金属复合管的 焊接工艺评价十分重要。本文以某焊接工艺制做的 L245/825 复合管焊缝为研究对象，对 L245/825 机械复合管直焊缝和环焊缝在 NACE A 溶液中的抗 SSC 性能，在模拟工况下的抗电 化学腐蚀性能和抗开裂性能进行了室内评价。并利用天东 5－1 高酸性气井在线腐蚀试验装 置进行了现场试验验证。室内试验和现场试验评价表明，L245/825 机械复合管直焊缝和环 焊缝在 H2S 和 CO2 共存条件下具有良好的抗电化学腐蚀性能和抗环境开裂性能，所选用的焊 接工艺可靠，研究成果为高含硫气田地面管线的选择和焊接施工提供了依据。 关键词：H2S；CO2；L245/825 复合管；焊缝；腐蚀 中图分类号：TE9 Study on Corrosion Resistance of Lined Steel Pipe Welding Gap in Highly Acidic Environment ZENG Dezhi1,2, HUANG Liming2, GU Tan2, YUAN Xi2, HUO Shaoquan2, SHI Taihe1 (1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), ChengDu 610500; 2. Southwest Oil and Gas Field Company, ChengDu 610213) Abstract: X Gas fields of Sichuan contain about 17% of hydrogen sulfide, and 10% of carbon dioxide. Chloride ion content is about 20mg/l in the gas field water. And pressure of surface lines is about 9Mpa. The surface lines are facing severe corrosion challenges, and then using clad pipe is a reliable and cost-effective anticorrosion measure for this application. However, clad pipe welding involves dissimilar steel welding, which is more difficulty, and the anticorrosion alloy will be diluted by extra carbon steel, and anticorrosion performance will be affected. So, it is necessary to make corrosion evaluation for welding technology of clad pipe. In this paper, L245/825 welding gap of clad pipe was researched, the anti-SSC performance in NACE A solution, stress corrosion cracking and electrochemical corrosion behavior of L245/825 straight welding gap and L245/825 ring welding gap were studied by laboratory experiments. Then the experiments were rerun in the corrosive environment found in the TianDong