This is a specialty service provided by various companies to assist the oil company in drilling a well that starts at one place on the surface of the earth and ends up at a specific target underground. This can also refer to horizontal drilling or extended reach drilling. The tools and techniques are similar for each of these methods. There are numerous specialty tools used in directional drilling such as rotary steerable drilling motors, conventional drill motors, steering tools, bent-housing drilling motors, measurement while drilling (MWD) tools, logging while drilling (LWD) tools, and others. Each tool is used to be able to drill the type of well desired and to transmit information to the surface. This information is used to “steer” the drill bit in the desired direction. Directional drilling is expensive and manpower intensive. It is used primarily offshore but is also used extensively in the non-conventional gas plays for drilling horizontal wells and extended reach wells. Companies that provide this service and tools are Sperry Sun (owned by Halliburton), Schlumberger, Baker Hughes, Scientific Drilling Controls, Weatherford International. There are many niche companies that supply this service and tools as well. There is not a recognized industry leader.