Direct Rotary Drilling Services by Hitech Drilling Engineers

In the Direct Rotary Drilling Services method, the borehole is advanced by rapid rotation of a drill bit mounted on the end of the drill rods. The bit cuts and breaks the material at the bottom of the hole into small pieces (cuttings). The cuttings are removed by pumping drilling fluid (water or water mixed with a fluid enhancer, such as bentonite) down through the drill rods and bit and up the annulus between the borehole and the drill rods. The drilling fluid also serves to cool the drill bit and stabilize the borehole wall, to prevent the flow of fluids between the borehole and surrounding earth materials, and to reduce cross-contamination between aquifers.

Despite these obstacles, direct-mud rotary drilling can be the best alternative, especially for deep wells or wells completed into well-lithified rocks. When direct-mud rotary methods are used, hole diameters should be 3 inches to 5 inches larger than the outer diameter of the well casings to allow effective placement of filter and sealing materials. Two-inch diameter monitoring wells should, therefore, be installed within 5.5-inch or larger holes.