新型液压滑套式随钻安全接头的研制

A novel hydraulic sleeve-type drilling safety joint

海洋深水钻井具有高风险、高投资和高技术的特点,一旦发生井下钻井事故,则损失巨大,如何迅速解除卡钻事故,降低钻井风险和事故损失是当前钻井工作的当务之急。在对钻井事故处理不断探索和总结的基础上,针对现有倒扣式和剪断式安全接头结构上的局限性和缺陷,研制出了一种能很好地处理井下卡钻事故的新型随钻安全接头。其工作原理为:在正常钻井作业中,它连接在钻具易卡部分的上端,当遇卡钻事故时,停钻、停泵,拆下回压凡尔以上工具(钻具内水眼需畅通)向钻具内投入钢球,接上方钻杆,开泵憋压使钢球入座滑套上端;由于泵压的上升,推动中心滑套剪断定压定位螺钉,使中心滑套上月牙键脱离键槽;当泵压下降后停泵,然后正转钻具,使上下反扣接头处分开,提升、取出钻具;然后再进行下一步套铣、打捞工作。对该工具进行了详细的强度分析计算,室内试验和在渤中34-5油田的两口井中使用表明,该安全接头具有安全可靠、操作简单、处理事故快等特点。

Deep water drilling is featured by high risk,high investment and high technology.Any downhole accident means a great loss.So how to free the sticking timely to reduce drilling risks and loss is urgent for drilling operation.Through study and analysis of previous experiences in sticking freezing,considering the limitations and defects of now available backoff type and shear type safety joints,a novel drilling safety joint was developed.It works effectively to solve the problem of downhole sticking.During normal drilling operation,it is connected above the tool where the sticking point is possibly to be.Once any sticking occurs,stop drilling and stop pump,and dismount tools above the back pressure valve (to ensure a way through the nozzles of drilling tools) before dropping a steel ball down the drilling tools.Then connect the kelly,and start the pump and hold the pressure to seat the steel ball on top of the sliding sleeve.If pressure increases,the central sliding sleeve will be pushed to shear the locating screw at a certain pressure,the upper key will go out of the key seat on the sliding sleeve.After the pressure drops,stop the pump,and turn the drill string clockwise,the upper and lower left-hand joints will disconnect.Then the drilling tools can be lifted out of the hole.The subsequent milling or fishing job will be finally conducted.The detailed strength calculation,lab experiment and field application on two wells at the Bozhong 34-5 Oilfield all prove this safety joint is safe,reliable,easy to operate and timely in sticking freezing.