Oil and gas borehole drilling implies using rotational method exclusively, carrying the rock particles to the surface through circulating fluid jet. Depending on the location of the engine the drilling techniques are divided into two major groups: rotor drilling, when the engine is installed on the surface, activating the drill bit at the bottom by rotating the entire drill string and downhole motor drilling that demands using a drill motor or turbine when the engine is located close to the borehole above the drill bit. Read More →