油气井钻进的经验表明 ,随着钻井深度的增加钻头的工作指标就下降 ,其主要原因是被破坏的岩石井底条件的改变。研究孔隙、地层、差动和总的水静力、水动力压力 ,以及岩石的力学特性等影响因素十分必要。很多实验室已经对上述因素如何影响岩石井底条件作了研究 ,并得出以下结论 The experience of oil and gas well drilling shows that the working index of the drill bit decreases as the drilling depth increases, mainly due to the change of the rock bottom conditions of the damaged rock. It is necessary to study the influencing factors such as pore, formation, differential and total hydrostatic pressure, hydrodynamic pressure and mechanical properties of rock. Many laboratories have studied how the above factors affect rock bottom conditions and have concluded that