围压下牙轮钻头单齿对不同岩石的破岩试验

为牙轮钻头的设计提供可靠的试验数据，利用模拟深井井筒试验架模拟深井钻井环境，选取具有代表性的3种岩心进行试验，测量得到了牙轮钻头单齿在不同的围压条件和岩石下载荷、位移、围压-单位能量破碎体积以及围压-破碎坑体积等试验数据。对试验结果进行分析，得到了围压作用下对于所试验的岩石和齿形，压入载荷和压入位移成线性关系；岩石破碎坑的体积随压入载荷的增加而减小；在以相同齿形压入相同岩石的条件下，岩石的破碎面积和体积随围压的增加而减小。在相同的岩石和相同围压的条件下，抛物线形齿破碎岩石所需载荷最小，楔形齿次之，球齿所需载荷最大。同时还得到了岩石性能对破碎效率的影响规律以及破碎比功随破碎体积的变化规律。

EXPERIMENTAL RESEARCH ON ROLLER BIT''''S SINGLE TOOTH CUTTING ON DIFFERENT ROCKS UNDER CONFINING PRESSURE

By means of simulating deep hole conditions and by using three kinds of representative cores, experimental data of the load and displacement, confining pressure-rock breaking volume by unit energy and confining pressure-breaking pit's volume are measured for cone bit's single tooth under different confining pressures. Through analysis it is concluded that for a given rock and given tooth profile, the cut in displacement (depth) is in a linear relationship with cut in load, the volume of breaking pit decreases with the increased cut in load, and the rock breaking area and volume will decrease with the increased confining pressure for the same tooth profile cutting into same rocks. Under the same confining pressure for the same rock, the load required for of paracurve tooth to break rock is the smallest, wedge tooth requires a bigger load, and the spherical tooth requires the biggest one. Also the effects of rock properties on breaking efficiency and the variation rules of rock breaking specific power with the breaking volume are summarized.