CDD110B型旋铣引鞋强度及流场特性分析

Analysis of Strength and Flow Field Characteristics of CDD110B Rotary Milling Guide Shoe

为提高通井作业中井壁光滑性和有效性,设计了一种新型井下螺旋式动力修整工具。旋铣引鞋是该动力修整工具的重要部件,具有井壁修整和通井双重功能。根据旋铣引鞋的工作环境,利用数值模拟方法分析了其在不同钻压、扭矩、排量、转速下的强度及液流特征。分析结果表明:旋铣引鞋的最大应力和最大变形量均随扭矩和钻压的增加而增加,最大变形位置分布于后切削刃和叶轮上,最大应力在旋铣引鞋腰部与后座连接处;旋铣引鞋通过流体在其内部形成的高强度涡流对井壁形成的切削修整能力随转速和流量的增加而增强;钻头处所受压力最大并且随流量的增加而增加;在流量从25 L/s增加到35 L/s的过程中,旋铣引鞋的压降、扭矩和效率均有所增加,其中压降增加77.14%,扭矩增加40.00%,效率增加42.10%;其最优工况点时的转速为75 r/min,流量为35 L/s,压降最大为0.124 MPa,效率最高为47.25%,扭矩最大达11.86 kN·m。研究结果可为旋铣引鞋的结构优化与改进提供技术指导。

In order to improve the smoothness of side wall and the effectiveness of drifting operation,a new downhole spiral power dressing tool was designed.As the key part of the power dressing tool,the rotary milling guide shoe has the dual functions of sidewall dressing and well drifting.According to its working environment,the strength and fluid flow characteristics under different WOBs,torques,displacements and rotational speeds were analyzed by using the numerical simulation method.The results show that the maximum stress and the maximum deformation of the rotary milling guide shoe increase with the increase of torque and WOB;the maximum deformation is distributed on the rear cutting edge and impeller;and the maximum stress exists at the connection part between the waist and the back seat of the rotary milling guide shoe.The cutting and dressing ability of the rotary milling guide shoe on the sidewall comes from the strong eddy current produced by the fluid in the rotary milling guide shoe,which increases with the increase of the rotational speed and flow rate.The pressure on the drill bit is the highest and it increases with the increase of flow rate.When the flow rate increases from 25 L/s to 35 L/s,the pressure drop,torque and efficiency of the rotary milling guide shoe increase.Particularly,the pressure drop increases by 77.14%,the torque increases by 40.00%and the efficiency increases by 42.10%.The optimal operating condition is at the rotational speed of 75 r/min and the flow rate of 35 L/s.Under this optimal condition,the maximum pressure drop is 0.124 MPa,the maximum efficiency is 47.25%,and the maximum torque is 11.86 kN·m.The research results provide technical guidance for structural optimization and improvement of rotary milling guide shoes.