酸性气田防腐蚀技术研究及应用

Research and Application of Anti-corrosion Technology in Sour Gas Fields

在含硫气田的开发过程中,由于H2S、CO2、Cl-以及元素硫等腐蚀因素的存在,导致材料存在不同程度的腐蚀。针对这种情况,先后采用常压腐蚀评价、高压腐蚀评价、动态高压腐蚀评价以及现场在线腐蚀评价等电化学腐蚀评价方法,综合分析后认为室内腐蚀评价方法与现场在线腐蚀评价方法相结合能较好地反映现场材料的腐蚀状况,并研究了主要腐蚀影响因素对材料腐蚀的影响。在此基础上,形成了一套以材料防止SSC、缓蚀剂防止电化学腐蚀为主的技术措施。评价了碳钢、耐蚀合金钢以及玻璃钢和内衬材料的耐蚀性能,并对这些材料在现场的耐蚀性能进行总结。针对目前川渝气田采用的碳钢+缓蚀剂的防腐工艺、所用的缓蚀剂及其效果进行了总结。结合现场应用,对目前常用的4种监测方法进行了评述。最后对川渝地区下一步气田防腐蚀工作提出了建议。

In the exploitation processes of sour gas wells,the presence H2S、CO2、Cl-can cause different degrees of corrosion behavior.Based on these situations,the electrochemical corrosion evaluation methods including normal pressure corrosion evaluation,high pressure corrosion evaluation,dynamic high pressure corrosion evaluation and on-line corrosion evaluation were used.After the integrative analysis,it was determined that the corrosion properties of on-line materials were preferably reflected through combination of laboratory and on-line corrosion evaluation methods.Technology mainly about SCC prevention using special materials and electrochemical corrosion prevention through injecting corrosion inhibitors was formed based on the further understand of all kinds of corrosion influence facts.In this paper,the corrosion resistances of carbon steel,corrosion resistance alloy,GFRP and lining material in laboratory and on-line conditions were separately studied.Furthermore,the effects of corrosion inhibitors currently used in Sichuan and Chongqing gas fields were summarized contraposing anti-corrosion technology using the carbon steel combining with the corrosion inhibitor.In addition,in order to resist the corrosion of annulus,anti-sulfur corrosion inhibitor which can prevent CO2 and O2 corrosion was used for gas wells with packer.Finally,the materials corrosion and protection testing were detected on-line by weight loss method,ER probe method,LPR probe method,hydrogen probe method,ultrasonic measuring thickness method,Fe ion analysis and corrosion inhibitor residual concentration analysis method.