气井管柱腐蚀机理研究及防治

文23气田是一个整装块状砂岩气田，主块气井不产地层水，只含少量凝析水。投产5年后陆续发现生产管柱大都腐蚀穿孔，严重的则断裂落后，研究发现是由天然气中CO2气体与凝水或地层水作用形成的碳酸水腐蚀。且腐蚀速度及腐蚀程度主要与气井产CO2总量，CO2分压，气流速度密切相关。气井应用加注缓蚀剂，应解决注药工艺及分散性问题。加强对CO2井内监测，及时进行工况诊断，定期检换生产管柱，改进油管节箍组装结构，而优质防腐涂层是延长气井寿命的重要措施。

The Corrosion Mechanism of Gas Well Production String and Its Protection

Wen-23 gas field is a clumpy sandstone gas field.It doesn't produce fromation water,but has less condensate water.After putting into production for 5 years,most production strings are corroded.Through research,the corrosion mechanism of production string is found,and corrosion speed and degree of corrosion is relative to CO 2 amount,CO 2 partial pressure and gas flow velocity of gas well.In order to protect the string corrosion, a series of measures are adopted,such as:strengthen the monitoring of CO 2 in well;periodically check and exchange production string and improve the assembly structure of tubing coupling.But the most important measure of extending the life-time of gas well is to use quality anti-corrosion insulation.