天然气管道不停输带压封堵施工创新技术

Leakage blocking with pressure in gas pipelines under non-stop service

天然气管道不停输带压封堵技术可有效避免资源浪费和环境污染,同时还能减少下游天然气用户的经济损失。为此,在比较膨胀筒式带压封堵器和皮碗式带压封堵器的优缺点基础上,选取前者进行了深入的应用研究。为了使该技术在生产实践中更加安全、规范,通过厂房试验、现场试验以及不断地技术改革和创新探索,最终形成了以下天然气管道不停输带压封堵施工创新技术:①将短管与封堵堵盘连体放回原位,解决清管卡球问题;②减小气流压差对膨胀筒就位过程的影响;③缓慢泄压,减少管口对封堵胶皮的剪切作用;④进行压力平衡,减少压差对封堵作业的影响;⑤开孔引气泄压动火施工。应用该项技术,中国石油新疆油田公司2007—2010年共完成了大小封堵52次,封堵压力最高达到3.14MPa,封堵口径达到500mm,节省了天然气放空燃烧和注氮气置换费用,节约资金达千万元。

The leakage blocking with pressure in gas pipelines under non-stop service can not only effectively avoid resource waste and environment pollution but reduce the economic loss for downstream natural gas users.This paper hereby makes a comparison between cylinder-type and cup-type plugging devices and an in-depth analysis has been made of the former.In order to make the above technology safer and better in accord with regulation,tests in the plants,on-site tests,and continuous technical research and improvement have been conducted to finally achieve the following innovative techniques.(1) The conjunct short tube and the plugging plate are placed in situ in order to solve the problem of spherical pig blockage.(2) The impact of the air flow pressure difference is reduced on the expandable cylinder preparation.(3) The pressure is released slowly to reduce the shearing action caused by the orifice on the plugging gum.(4) The pressure balancing is done to reduce the impact of pressure difference on the plugging operation.(5) An exhaust opening is cut to release pressure and start construction.The PetroChina Xinjiang Oilfiled Company had completed pipeline leakage blocking operation for 52 times during 2007-2010 by using the above innovative techniques with the maximum blocking pressure of 3.14 MPa and the maximum diameter of 500 mm,which not only avoided the waste of natural gas but saved the costs on nitrogen injection,as a result,totally 10 million Yuan RBM has been saved.