塔河9区高含H_2S凝析气藏地面集输管道防腐蚀选材与内涂层防腐蚀考察

Anti-Corrosion Material Selection and Undercoat Investigation for Gas Gathering Pipelines in Condensate Reservoir with High-Concentration H_2S in the 9th District of Tahe Oilfield

塔河油田9区生产层为奥陶系,采出介质具有"高H_2O、高H_2S、高CO_2、高Cl^-、低pH值"的"四高一低"强腐蚀特性,集输工况具有高温、高压特点,现有普通碳钢管材质已无法适用现场使用寿命要求。通过分析腐蚀环境,开展了抗腐蚀管材评价试验、内涂层适应性评价试验。基于试验结果进行技术可行性分析与全生命周期经济性对比分析,推荐9区地面单井集输管道采用825内衬双金属复合管,天然气外输管线采用L245NS抗硫管材+缓蚀剂,可为治理"H_2O、H_2S、CO_2、Cl^-"腐蚀环境下的集输管道腐蚀提供借鉴。

The production strata of the 9th district of Tahe oilfield is the Ordovician, and the produced medium is of ＂four high and one low＂ severe corrosive characteristics-＂high H2O, high H2S, high CO2, high Cl^-, low pH value＂. Besides, the gathering and transportation condition has the characteristics of high temperature and high pressure. Currently, the existing ordinary steel pipe has been unable to meet the requirement of the service life. On the analysis of corrosion environment, the evaluation test was conducted to optimize anticorrosion materials and inner coating. Technical feasibility analysis and life-cycle economy comparative analysis were conducted based on the experimental results. Results showed that 825 double metal composite pipe was recommended to be used in the gathering pipeline, and the method of L245NS ＋ corrosion inhibitor was suggested to be used in natural gas export pipeline. This work provided some references to resolve the corrosion problem in corrosion environment containing H2O, H2S, CO2 and Cl^-.