To achieve the secondary production in multistage fracturing wells of tight oil, milling tools are usually used to remove the multistage fracturing ball seats to achieve production with a large diameter in later. In this paper, first of all, the working mechanism of milling tools for multistage fracturing ball seats was studied and a mechanical analysis model of single abrasive grain was established. Then, an experimental system for milling tools was developed, and the experimental tests of the flat, the blade, and the slope milling tool were conducted in order. Besides, the morphology of chips and the surface morphology of the workpiece after the experiment were analyzed. Also, the working performance of milling tools was evaluated from the perspectives of working safety, working efficiency, and wear resistance of the milling tool. The results show that the torque of the milling tool increases nonlinearly with the increase in the cutting depth of the abrasive grain and increases linearly with the increase in the cutting width. Also, the chips are irregular particles and the size is mainly from 10 to 50 μm. So, the chips should be pumped up with a small pump pressure and a large displacement. Besides this, the cutting depths of the abrasive grains are from 216.20 to 635.47 μm and the bottom surface of the milling tool should be eccentric to avoid the zero point of cutting speed. Furthermore, the torque of the slope milling tool is 23.8% larger than that of the flat milling tool, which is also 30.4% smaller than that of the blade milling tool. Compared with the flat milling tool, the working efficiency of the blade milling tool improves by 79.9% and the slope milling tool improves by 111.1%. Also, the wear resistance of the blade milling tool decreases by 102.7%, while the slope milling tool declines by 32.6% when compared with the flat milling tool. Therefore, the slope milling tool has the characteristics of moderate torque, stable working conditions, the highest working efficiency, and fine wear resistance, which is preferably used to mill multistage fracturing ball seats. This study provides a theoretical basis and guidance for milling multistage fracturing ball seats on-site and realizing production with a large diameter in later stages of multistage fracturing wells.

为了在致密油的多级压裂井中实现二次生产，通常使用铣削工具去除多级压裂球座，以在以后实现大直径的生产。本文首先研究了多级压裂球座铣削刀具的工作机理，建立了单磨粒力学分析模型。然后，开发了用于铣削刀具的实验系统，并依次进行了平面，刀片和倾斜铣削刀具的实验测试。此外，分析了切屑的形态和实验后工件的表面形态。此外，从铣削工具的工作安全性，工作效率和耐磨性的角度评估了铣削工具的工作性能。结果表明，铣刀的扭矩随磨粒切削深度的增加而非线性增加，随切削宽度的增加而线性增加。另外，碎片是不规则的颗粒，尺寸主要为10至50μm。因此，应以较小的泵压和较大的排量来抽吸切屑。除此之外，磨粒的切削深度为216.20至635.47μm，并且铣刀的底面应偏心以避免切削速度的零点。此外，倾斜铣刀的扭矩比平面铣刀的扭矩大23.8％，也比刀片铣刀的扭矩小30.4％。与平板铣刀相比，刀片铣刀的工作效率提高了79。9％，坡口铣刀提高111.1％。此外，与平面铣刀相比，刀片铣刀的耐磨性下降了102.7％，而斜角铣刀则下降了32.6％。因此，该斜面铣刀具有扭矩适中，工作条件稳定，工作效率最高，耐磨性优良的特点，优选用于多级压裂球座的铣削。该研究为现场碾压多级压裂球座和在多级压裂井后期实现大直径生产提供了理论依据和指导。斜铣刀具有扭矩适中，工作条件稳定，工作效率最高，耐磨性好等特点，优选用于多级压裂球座的铣削。该研究为现场碾压多级压裂球座和在多级压裂井后期实现大直径生产提供了理论依据和指导。该斜面铣刀具有扭矩适中，工作条件稳定，工作效率最高，耐磨性好等特点，优选用于多级压裂球座的铣削。该研究为现场碾压多级压裂球座和在多级压裂井后期实现大直径生产提供了理论依据和指导。