冷冻暂堵技术在赵兰庄高含硫井换装井口中的应用

Application of Freezing Temporary Plugging Technology in Rehandling Wellhead of Zhaolanzhuang High-sulfur Well

在华北油田赵兰庄高含硫隐患井治理中,鉴于安装井口和修复换装受腐蚀损坏井口施工时的安全需要,施工前必须首先对安装井口装置载体的油层套管及井筒进行临时封堵,采用了井口冷冻暂堵技术,通过在套管外围采用干冰降温,使进入井筒内的暂堵剂冻结,形成冰冻段塞密封井筒,封隔井内压力和阻止H2S逸出通道,其后自然融化。该技术具有快速冷冻、密封效果好、成本低等优势,在赵12等井得到有效的应用,对以后类似井有重要的借鉴作用和一定的现场指导意义。

The wellhead device plays an important role in the pressure control and flow control. During the treatment with Zhaolanzhuang high-sulfur hidden wells affiliated to Huabei Oilfield,to meet safety demand of wellhead installation and repairing and rehandling of corrosion damage wellhead construction,temporary plugging must be carried out on reservoir casing and wellbore of wellhead device carrier before field operation. The wellhead freezing temporary plugging technology is adopted. Through the use of dry ice cooling outside casing,temporary plugging agent in the wellbore is frozen,forming a frozen slug which melts naturally thereafter and sealing the wellbore. The well is pressurized and prevents H2S from escaping. This technology has the advantage of quick freezing,effective sealing and low cost. In the application of Zhao12 well, freezing temporary plugging technology has been effectively carried out,which has important reference and certain field guiding significance for similar wells in the future.