集输工程绝缘接头非保护侧腐蚀防护技术研究

Study on corrosion protection technology of non-protective side of insulatingjoint in gathering and transportation engineering

为减缓绝缘接头非保护侧钢管发生内腐蚀,需对绝缘接头非保护侧内壁腐蚀原因、腐蚀机理和影响因素进行分析。通过测试气田水电导率和总矿化度,计算气田水电阻率,总结气田水电阻率和总矿化度的关系,进一步确定不同工况绝缘接头保护侧内防腐层长度及其计算方法,并计算不同工况内防腐层长度和腐蚀速率。结合国内外相关标准和实际工程经验,综合考虑长期有效性、安装空间、制造和运输、运行维护方便性等因素,提出地面安装绝缘接头并辅以合理长度内防腐层的措施能缓解绝缘接头非保护侧内壁腐蚀,且可实施性强。地面安装绝缘接头并通过绝缘接头内防腐层长度计算方法计算出合理长度的内防腐层可为油气田内部集输工程绝缘接头设计、安装及维护提供指导。

In order to slow down the internal corrosion of carbon steel pipes on the non-protective side of insulating joints,this paper analyzes the causes,mechanisms and influencing factors of the internal corrosion on the non-protective side of insulating joints.By testing the conductivity and total salinity of gas field produced water and calculation of the electrical resistivity,this paper summarizes the relationship between the resistivity and total salinity of gas field produced water.The calculation methods for the length of the internal corrosion protection coating on the protective side of insulating joints under different conditions are further determined.Then the length of the internal corrosion protection coating on the protective side and corrosion rate of insulating joints under different conditions is calculated.Together with relevant standards and actual engineering experience at home and abroad,taking into account the long-term effectiveness,installation space requirement,manufacturing and transportation,operation and maintenance accessibility and other factors,it is proposed that the measures of ground installation of insulating joint,supplemented by a rational length of internal corrosion protection coating,are effective and feasible in mitigating the internal corrosion on the non-protective side of insulating joints.The ground installation of insulating joint with a reasonable length of internal corrosion protection coating provide guidance for the design,installation and maintenance of insulating joints in gathering and transportation engineering within in oil and gas fields.