Sidetracking
The process of drilling a deviated section initiated from the already drilled part of the original wellbore is called Sidetracking a well. Sidetracking can be planned, intentional, or maybe accidental as well. A sidetrack can be initiated from either a cased hole or an open hole depending on the reasons for a sidetrack.
Sidetracking a well requires a specialized set of equipment, exhaustive planning, and directional drilling expertise. A well can be sidetracked either from the vertical, deviated, or horizontal part of the original wellbore depending on the reasons for sidetracking.