用于深水套管切割的水力式内切割装置设计及研究

随着中国进入深水勘探阶段,机械式割刀越来越难以快速、高效地进行深水套管切割。针对此问题,在课题组前期研究的基础上,设计了一种用于深水套管切割的水力式内切割装置,并针对其结构特点,对其工作原理进行了介绍。结合水力式内切割装置的结构与工作原理,建立了活塞与割刀的几何模型,分析了割刀刀尖切割半径与活塞位移间的关系,并得到了工具切割套管所需最大扭矩和井口转盘所需提供的最小扭矩的关系式;最后通过建立的相关数学模型,借助MATLAB软件对影响其切割效率的因素进行了分析,结果表明:(1)随着割刀端面角的增大,活塞所需移动位移也增大但工具切割扭矩却降低;(2)工具切削扭矩随钻井液驱动力的增加而增加;(3)井口扭矩随切削深度的增加而增加,在切削深度不变时,井口扭矩随着转速的增大而增大,并给出了最好切削效果下的割刀端面角和切割转速的建议。研究结果对用于深水套管切割的水力式内切割装置设计和优化具有参考价值。

Design and Research of Hydraulic Internal Cutting Device for Deep Water Casing Cutting

As our country enters deep water exploration stage, it is increasingly difficult for mechanical cutter to carry out deep water casing cutting quickly and efficiently. Aiming at this problem, a hydraulic internal cutting device for deep water casing cutting is designed on the basis of previous research, and the working principle is introduced for its structural characteristics. Based on the structure and principle of hydraulic internal cutting device, the geometrical model of piston and cutter is established, the relationship between the cutting radius and the piston displacement is analyzed, and the relation between the maximum torque required for tool cutting casing and minimum torque required for wellhead rotary table is obtained. Finally, the factors affecting the cutting efficiency are analyzed with MATLAB software based on the establishment of relevant mathematical models. The results show that: 1) the piston displacement increases with the increase of cutter face angle, but the cutting torque of the tool decreases; 2) the tool cutting torque increases with the increase of drilling fluid driving force; 3) the wellhead torque increases with the increase of cutting depth; When the cutting depth is constant, the wellhead torque increases with the increase of rotational speed. What"s more, the suggestions for cutter face angle and cutting speed of cutter with the best cutting effect are given. Conclusions of the study may provide necessary reference for the design and optimization of hydraulic internal cutting device for deep water casing cutting.