The two-step Underreamer has six cutting arms and these can be made of tungsten carbide inserts or polycrystalline diamond compact cutters (PDC) has a lower connection to attach a drill bit or a bull’s nose and in turn could be combined with set of arms of different sizes or composition to perform a much faster and more efficient drilling in a single descent.
Available Double Step Underreamer Tools
Body diameter: 5 3⁄4 in.
Opening diameters: 9, 11, 13, 16, 20 in. (Combined different diameters below and above)
Top connection: (IF box) 3 1⁄2 in.
Bottom connection: (REG box) 3 1⁄2 in.