杏北油田聚驱注入系统管道腐蚀因素分析

Pipeline Corrosion Factor Analysis of the Polymer Flooding Injection System in Xingbei Oilfield

为揭示油田聚驱注入管道严重腐蚀原因,以杏北油田为例,对聚驱注入系统失效管道进行了宏观观察及微观分析,并根据现场工况设计了室内模拟实验。观察了失效管段内涂层及基材,分析了腐蚀坑的形貌、成分及腐蚀产物,探讨了聚驱注入介质流速、含氧量、聚合物质量浓度对腐蚀速率的影响和作用。实验结果表明:管道内涂层失效是导致管道穿孔的重要因素;管道基体存在原发性缺陷大大降低了管道的使用寿命;细菌,特别是硫酸盐还原菌的存在加速了管道腐蚀;溶解氧的存在显著增加了腐蚀速度。以上几个因素是导致杏北油田注入系统严重腐蚀的主要原因。

In order to reveal the reason of severe corrosion of oilfield polymer flooding injection pipe-lines,taking Xingbei Oilfield as an example,the ineffective pipeline of the polymer flooding injection system is macroscopically observed and microscopically analyzed,and the laboratory simulation test is designed according to the field conditions.The inner coating and basic material of the ineffective pipe-line section are observed,the morphology,ingredient of corrosion pits and corrosion products are ana-lyzed,and the influence and effect of injection medium flow velocity of polymer flooding,oxygen content and polymer mass concentration on the corrosion rate are discussed.The experiment results show that the failure of pipeline inner coating is an important factor for pipeline perforation;the exis-tence of primary defects in the base of the pipeline greatly reduces the service life of the pipeline;the presence of bacteria especially the sulfate reducing bacteria accelerates corrosion;the presence of dis-solved oxygen greatly increases the corrosion speed of pipelines.The above factors are the main factors that lead to the serious corrosion of the injection system in Xingbei Oilfield.