【摘要】 本文对使用三牙轮钻头时在井底岩面上形成三凸起型式的原因进行了深入详细的研究和探讨，同时对三凸起型式存在的一些争议问题进行了较全面的分析和阐述，得到了一些有实际意义的结论，为以后分析和诊断钻头及钻柱在井下的振动特征奠定了理论基础更多还原

【Abstract】 In this paper the forming mechanism of three lobes pattern on the bottomhole rock surface is studied deeply when the tricone bit is used. At the same time some questionable problem about three lobes pattern are analysed round about. Some practical conclusions are obtained. It is theoretical basis to analyse and diagnose the vibration characteristics of bit and drillstring downhole.更多还原