Abstract: To solve the technical bottleneck problem of slow footage and rapid wear rate of milling tools for workover under complex wellbore conditions, the early recommended slope milling tool for workover was taken as the research object based on previous research. First of all, a mechanical analysis model of the abrasive grain based on the shear slip line theory model was established, and the quantitative relationship between abrasive grain angle and working torque of the milling tool was clarified. Then a single abrasive grain cutting simulation software based on the secondary development of ABAQUS in Python language was developed, and the parametric modeling of single abrasive grain cutting simulation model was realized. Besides, the milling tool for workover with single abrasive grain of different angles was developed and the cutting experimental tests were completed. At last, the preferred angle of the abrasive grain was determined from five aspects including angle type, chip formation process, chip morphology, cut scar morphology and work characteristics. The results show that the cutting force of the abrasive grain with zero angle has the fastest growth rate, the value of the abrasive grain with positive angle is the largest, and the value the abrasive grain with negative angle is the smallest with a smoothly fluctuating in the range of 642.5-785.3 N. With the increase of the angle of the abrasive grain from 0° to 45°, the chip volume gradually decreases, the chip length decreases from 5 mm to 2 mm, and the chip shape changes from roll-like type to irregular granular type. When the angle of the abrasive grain is 5° and 10°, the cut depth of the workpiece surface is the largest that reaching 1.0 mm. When the angle of the abrasive grain is 8°, the material removal mass is the largest that reaching 9.49 g, and the working torque is only 28.7 N ·m, which shows the working process is relatively smooth. Considering the working efficiency as well as working safety, the preferred angle of the abrasive grain on the slope milling tool for workover is -8°.

Key words: milling tools for workover, abrasive grain, cutting angle, operating characteristics, metal junk

摘要： 针对复杂井筒工况下修井磨鞋钻进慢、磨损快的技术瓶颈问题，以前期优选的旋进式修井磨鞋为研究对象，基于剪切滑移线理论模型建立磨粒力学解析模型，明确磨粒布齿角度与修井磨鞋工作扭矩定量关系，基于Python语言的ABAQUS二次开发编写单磨粒切削仿真软件，实现单磨粒切削仿真模型参数化建模，试制不同布齿角度单磨粒修井磨鞋并完成实验测试，从布齿类型、成屑特征、切屑形态、切痕形貌和工作特性5个方面确定优选布齿角度。研究结果表明，零布齿角磨粒切削力增长最快，正布齿角切削力数值最大，负布齿角磨粒切削力数值最小且平稳波动变化，波动范围为642.5~785.3 N。随着磨粒布齿角度在0°~45°范围内增大，切屑体积逐渐减小，切屑长度由5 mm减小为2 mm，切屑形状由卷筒状变为不规则颗粒状。当布齿角度为5°和10°时，实验工件表面轮廓深度最大，达到1.0 mm。当磨粒布齿角度为8°时，材料去除质量最大，达到9.49 g，同时工作扭矩仅为28.7 N ·m，工作过程较为平稳。综合考虑工作效率和工作安全，旋进式修井磨鞋的优选布齿角度为-8°。

关键词: 修井磨鞋, 磨粒, 布齿角度, 工作特性, 金属堵塞物