Directional drilling
Directional drilling Directional drilling (or slant drilling) is the practice for drilling non-vertical wells. It can be broken down into three main groups: Oilfield Directional Drilling, Utility Installation Directional Drilling (or H.D.D. or Horizontal Directional Drilling) Directional boring, and SIS (surface In Seam), which horizontally intersects a vertical well target to extract coal bed methane.