陇东油田Y区块油井管柱腐蚀特性及防护技术

Corrosion Behavior and Protention Technology for Strings in Oil Well of Y District in Longdong Oilfield

对陇东油田Y区块油井管柱腐蚀的现场情况开展详细调研,抽取现场样本井采出水进行水质分析。在采出水中对N80钢进行动/静态腐蚀试验,通过扫描电镜观察、能谱分析、电化学试验等分析了Y区块油井管柱腐蚀的主要特性。结果表明:N80钢不仅发生了均匀腐蚀,还发生了CO_(2)、H_(2)S等酸性气体腐蚀和SRB细菌腐蚀;在结垢趋势强的采出水中,形成的垢致密,附着于腐蚀界面起到防腐蚀作用,在结垢趋势相对弱的采出水中,腐蚀产物疏松,附着于界面而加速了局部腐蚀。通过对腐蚀特性研究,提出管柱材料处理和优选缓蚀剂HSJ-02(用量150mg/L并配合适宜含量的杀菌剂)的综合防腐蚀措施,该防腐蚀措施使3a内现场腐蚀开井维护作业量降低了56%。

The field situation of strings in oil well of Y district in Longdong oilfield was investigated in detail.Water quality analysis of produced water from field sample wells was conducted.The main characteristics of string corrosion in oil well of Y district were analyzed by observation through scanning electron microscopy,energy spectrum analysis and electrochemical testing in the dynamic/static corrosion test of N80steel in the produced water.The results show that N80steel was not only uniformly corroded,but also corroded by CO_(2)and H_(2)S acidic gases and SRB bacteria.In the produced water with a strong scaling tendency,the formed scale was densely attached to the corrosion interface to prevent corrosion.In the produced water with a relatively weak scaling tendency,the corrosion products were loosely attached to the interface to accelerate localized corrosion.These anti-corrosion measures reduced field corrosion well maintenance operations by 56%over a period of three years.