摘要
钻井过程中钻具经常会因扭矩过大而"憋停",当扭矩达到某一值后钻具会突然快速释放,这种现象通常称为钻具粘滑。钻具的粘滑经常伴随井下震动,容易引发金刚石钻头崩齿,从而缩短钻头寿命,也会引起井下仪器(MWD/LWD)失效。钻具的粘滑跟井下钻具组合和所钻地层岩性有关。粘滑现象是一种阈值现象,即低于临界转速粘滑就会发生。软扭矩系统针对粘滑现象作用机理而研发,通过降低临界转速,有效地控制了钻具粘滑。该系统在长北气田进行了推广应用,从源头上消除了钻具粘滑现象,保护了钻头和井下仪器,应用效果良好。
Drilling string will be stopped rotation due to over-torque while drilling, and drilling string will be released suddenly when the torque reached the peak torque, this phenomenon is be called drilling string stick-slip. Drilling string is vibrating while stick-slip occurring, and results in teeth of PDC bit broken easily, so shorten bit life, and leads to down hole MWD/LWD lost signal. Drilling string stick-slip is related with BHA and formation. Stick-slip is one kind of threshold phenomenon, so will be happened when drilling string rotary speed lower critical rotary speed. Soft torque system is studied special for preventing stick-slip phenomenon through decrease critical rotary speed. This system has be applied in Changbei gas field widely and avoid drilling string stick-slip phenomenon, protect bit and down hole instruments. The application result is very effectieve.
出处
《石油化工应用》
CAS
2012年第12期51-55,共5页
Petrochemical Industry Application
关键词
钻具粘滑
扭矩
临界转速
软扭矩系统
振动
drilling string stick-slip
torque
critical rotary speed
soft torque system
vibration
