小直径带压切割工艺在顺南气田的改进和应用

Improvement and Application of Minor Diameter Cutting Technology under Pressure in Shunnan Gas Field

顺南气田因高温、高压,高含CO_2、H_2S等情况,井内管柱腐蚀严重,管柱通径变小,常规切割弹无法完成该地区施工井的切割施工任务,必须做出相应改进。先期的改进是,加厚切割弹外壁,适当提高承压能力(由80 MPa提至105MPa),调整药型罩结构,缩小切割弹外径(由68mm减小至60mm)。顺南5-2井和顺南401井的切割实践显示,切割弹未能将油管完全切除,两次切割油管均有4~6cm的粘连。后期是在原有改进的基础上为切割弹设计加装了一对扶正弹片,使切割弹发火前尽量在管柱中处于居中位置,解决因切割弹偏靠造成的间隙过大,威力不够的问题。顺南4井的实践表明,添加扶正弹片后小直径切割弹能顺利完成切割任务。

Shunnan Gas Field features high temperature, high pressure and highly containing CO2 and H2S, leading to serious downhole string corrosion, smaller string drift diameter, which make cutting operation impossible using common jet cutter. Two relevant improvements are made. The first improvement includes thickening external wall of the jet cutter to properly enhance its loading capacity, adjusting medicine type cover structure and shrinking exter- nal diameter of the jet cutter. And then a pair of centralizer shrapnels is installed in the jet cutter to ensure that the jet cutter is in the center of the string before it catches fire to solve the problem of insufficient power brought by ex- cessive gap due to the jet cutter＇s deviation. The application shows that the improved jet cutter finishes cutting opera- tion successfully.