Directional Drilling and Trajectory Design

Directional Drilling and Trajectory Design

Directional drilling may be considered the "intentional, controlled deflection of a wellbore to intersect pre-determined targets." In the early days when wooden derricks were erected so close that they touched each other, wellbores that were believed to be vertical occasionally intersected nearby wellbores, proving that the wells were in fact deviating from vertical. This was not directional drilling because this behavior was neither intentional nor controlled. Modern directional drilling is based on an understanding of the reservoir and how the wellbore should be constructed for its proper placement in the reservoir for optimum productivity.