Definitions for "HORIZONTAL DRILLING"
See Directional Drilling.
n: deviation of the borehole from vertical so that the borehole penetrates a productive formation in a manner parallel to the formation.
The newer and developing technology that makes it possible to drill a well from the surface, vertically down to a certain level, and then to turn at a right angle, and continue drilling horizontally within a specified reservoir, or an interval of a reservoir.