The percussionandrotarydrilling of hydraulic impactor may heighten drilling velocity several times, when it is been applying in drilling geothermic well.
液动冲击器冲击回转钻进技术应用于地热井钻进中，可以数倍提高钻进速度。
2
In rock drilling process with percussion-rotary drill rotating drilling tool bears two toques: dynamic torque which drives drilling tool into rock mass, and resistance torque of rock mass.