子洲-米脂气田气井腐蚀因素及腐蚀规律研究

随着子洲-米脂气田的大规模开发，产水气井及产水量的逐年增多，因腐蚀而引起的管筒穿孔、断脱，井口及集输管网渗漏问题的日渐突显，给气田生产造成了严重危害和经济损失。为了准确掌握井下油套管腐蚀状况，需要系统分析影响井下管串腐蚀的主要因素、腐蚀程度及防腐效果及进行腐蚀规律研究。本文主要对子洲一米脂气田生产井的腐蚀性影响因素及腐蚀规律开展研究，通过整理检测气田整体区块的气质、水质和凝析油基础物性，结合对井筒的腐蚀挂片试验，通过应用腐蚀机理研究，分析判定了子洲-米脂气田天然气属于微含硫、低含CO2干气气藏，气井存在的腐蚀和结垢趋势，气田腐蚀主要表现为CO2腐蚀，对CO2分压、pH值、H2S、凝析油等主要因素和次要因素进行了系统分析，将来为下一步筛选合理缓蚀剂提供理论依据。

Study on Corrosion Factors and Corrosion Rule of Gas Wells in Zizhou- Mizhi Gas Field

With large-scale development ofZizhou- Mizhi gas field, amount of water-production gas well and water production rate increase year by year. Because of muff perforation and dropout caused by corrosion, leakage problem of wellhead and gathering pipe network increase obviously, which has caused serious harm and economic loss for gas field production. In order to accurately know corrosion conditions of the underground oil casing, main influencing factors, corrosion degree, anticorrosive effect and corrosion law of the underground pipe string need be analyzed and studied. In this paper, corrosion factors and corrosion rule of gas wells in Zizhou-Mizhi gas field were studied. Physical properties of water, gas and condensate oil were detected, combined with wellbore corrosion coupon test, the corrosion mechanism was researched. The results show that Zizhou-Mizhi gas field belongs to micro sulfur dry gas reservoir containing low CO2 content, the gas wells have corrosion and scaling tendency, which is mainly caused by CO2 corrosion. Main factors and secondary factors such as CO2 partial pressure, PH, H2S, condensate oil were studied ,which can provide the theory basis for screening rational corrosion inhibitors.