为研究注入水中添加亚硫酸钠除氧剂控制注气井管柱氧腐蚀的有效性,为现场注气井管柱腐蚀防护提供依据,采用高温高压反应釜对注气井油管管材进行腐蚀模拟试验,利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和能谱仪(EDS)等对试样腐蚀产物膜的成分及结构进行表征,研究了除氧剂添加对管材腐蚀行为的影响,并初步讨论了其腐蚀机理。结果表明:因注氮气驱油工艺引入的溶解氧会对P110与P110S油管管材带来严重的腐蚀风险,并具有较高的局部减薄失效风险;P110与P110S管材的全面腐蚀速率分别达到1.511 mm/a与1.404mm/a,最大减薄速率达到12.085 mm/a与4.240 mm/a;通过在注入水中适量添加除氧剂,P110与P110S管材的全面腐蚀速率分别降低至0.035 mm/a与0.030 mm/a,有效地降低了管材的腐蚀风险。
In order to study the effectiveness of adding sodium sulfite in injected water to inhibit oxygen corrosion in gas injection wells and provide reference basis for corrosion protection in gas injection wells,using the high temperature and high pressure reactor to simulate the corrosion experiments for oil well pipes,the morphology and chemical composition of the corrosion product film on sample were studied by scanning electron microscopy( SEM),X-ray diffractometer( XRD) and energy dispersive spectroscopy( EDS). Furthermore,the effect of adding oxygen scavengers on the corrosion behaviors was analyzed,and the mechanism of oxygen corrosion in the gas injection wells was initially discussed.Results showed the dissolved oxygen introduced by nitrogen flooding would bring serious corrosion risk to P110 and P110 S tubing,as well as higher sensitivity of failure due to local thinning. Moreover,the general corrosion rate of P110 and P110 S reached 1. 511 mm/a and 1. 404 mm/a,and the maximum thinning rate reached 12.085 mm/a and 4.240 mm/a. Therefore,the entire corrosion rate of P110 and P110 S could be effectively reduced to 0. 035 mm/a and 0. 030 mm/a by adding the oxygen scavenger reasonably in the injection water,which could decreased effectively the corrosion risk of pipes.
Journal of Materials Protection
gas injection wells
oil well pipe