Abstract:Downhole motor is a drill tool which can transform energy form drill fluid into a dynamic of breaking rocks.Compared with traditional drill tools,there are some merits in the drilling process,such as high capacity usage ratio,low drilling cost and so on.In some westen developed country,downhole motor has been confirmed as one of the best drilling tools in directional well,cluster well,highly-deviated well,horizontal well and emergency rescue.Now,the downhole motor drill with low speed and high torque is the main direction to research.However,among the downhole motor drills at present,turbodrill has a character of high speed and high torque,which needs to coordinate with speed reducer to reduce its speed;positive displacement motor drills can realise low speed and high torque drilling easily,but they have a bad resistance to high temperature and high pressure;electric drill have a complex structure which confines its application.After the investigation and research to the drilling process at present,a new-type vaned drill was designed.Its working principle was similar to vane motor which applied the differential pressure of the vane to drive rotor to run.The new-type vaned drill was also easily to realize low speed high torque of drilling.