冲击类钻井提速工具专用PDC钻头设计与试验

Design and Test of PDC Bit for Impact Drilling Speed-up Tool

针对冲击类钻井提速工具与PDC钻头不匹配的问题,进行专用PDC钻头设计与试验。分析了冲击类钻井提速工具与地层的适应性,得出扭力冲击器适用于深部硬塑性地层,螺杆式液动冲击器适用于深部硬脆性地层。通过模拟的方法,分析了钻头长度、截面积等结构参数对冲击能量利用率的影响规律,得出钻头截面积越大、钻头长度越短,冲击类提速工具冲击能量利用率越高,越能发挥出工具的冲击破岩能力。基于以上分析,结合硬地层PDC钻头优化设计原则,设计了冲击类钻井提速工具专用PDC钻头,主体刀翼5～7个、双排高密度布齿,切削齿后倾角20～25°。试验结果表明,专用PDC钻头与冲击类钻井提速工具的匹配性良好,但也存在一定的不适应性,需要根据现场应用情况进一步优化,着力增强钻头的耐磨性、攻击性和抗冲击能力。

A special PDC bit was designed and tested for the problems of mismatching of between the impact drilling speed increasing tool and the PDC bit. The adaptability of the impact-type drilling speed-up tool to the formation was analyzed. It is concluded that the torsion impactor is suitable for deep hard plastic formation, and the screw-type hydraulic impactor is suitable for deep hard and brittle formation. The influence of structural parameters such as drill length and cross-sectional area on the impact energy utilization rate were analyzed through the simulation method. it is concluded that the larger the cross-sectional area of the drill bit with the shorter the drill bit length, the higher the impact energy utilization rate of the impact-type speed-up tool. Based on the above analysis, combined with the design principle of hard-layer PDC bit optimization design, a special PDC drill bit for impact-type drilling speed-increasing tools was designed. The main blade has 5~7 double-row high-density cloth teeth, and the cutting tooth has a back inclination angle of 20~25°. The test results show that the matching of the special PDC drill bit and the impact drilling speed-up tool is reasonable however with certain incompatibility, which needs to be further optimized.