腐蚀引起钻柱刺漏的机理分析及预防措施

详细分析了腐蚀引起钻柱刺漏的机理，得知：造成钻柱刺漏的主要原因是空气中的O2、地层中的硫化氢和二氧化碳、钻井液残液、钻井液中的盐类对钻柱的腐蚀和钻井液对钻柱的冲蚀。针对引起钻柱刺漏的原因，制定了去除钻井液中的O2、监测钻井液腐蚀性并加入相应的添加剂去除CO2和H2S、定期对钻杆进行检测、对存放的钻杆进行防腐处理、使用厚过渡区改进型钻杆等措施。在苏丹某区块现场实践证明，采取这些措施，由腐蚀引起的钻柱刺漏事故大大减少，在该区块的T-1井和D-1井钻进的3个月中，仅发生一次钻柱刺漏事故。

Mechanism Analysis and Preventive Measures of Drill String Washout Caused by Corrosion

The detailed analyses of drill string washout caused by corrosion indicate that such corrosion mainly results from oxygen in the air, hydrogen sulfide and carbon dioxide from formations, drilling fluid retained in the pipe, salts in the drilling fluid and drill string erosion by drilling fluids. Many countermeasures therefore are developed such as removing oxygen contained in drilling fluids, monitoring drilling-fluid causticities, eliminating carbon dioxide and hydrogen sulfide by adding additives into mud, inspecting drill stems periodically, anti-corrosion treatments for drill pipes in storages and using improved drill pipes with a thick transitional section, etc. Field tests with above measures in one block in Sudan show that frequency of drill string washout caused by corrosion was decreased greatly. There was only one case happened in three months while drilling T- 1 Well and D-1 Well.