Stand-alone, information-packed chapters of the 12th edition of the definitive rig operations manual, the new IADC Drilling Manual, are now available in convenient electronic form. More than 100 renowned technical experts contributed to the first major rewrite of the IADC Drilling Manual in 22 years.
[pdf] Directional drilling (or slant drilling) is the practice of drilling non-vertical . It can be broken down into four main groups: directional drilling, utility installation directional drilling, (horizontal directional drilling - HDD), and surface in seam (SIS), which horizontally intersects a vertical bore target to extract . Horizontal directional drilling bores underneath obstacles with a guided bit. The operator steers the bore head utilizing an angled pipe, pressurized fluids, and a steering tool that provides depth and positioning feedback.
[pdf] Wells are drilled directionally for several purposes: • Increasing the exposed section length through the reservoir by drilling through the reservoir at an angle.• Drilling into the reservoir where vertical access is difficult or not possible. For instance an oilfield under a town, under a lake, or underneath a difficult-to-drill formation.
[pdf] 
