Directional Sidetrack or Directional Redrill
Directional Sidetrack or Directional Redrill : (Abbreviated as S/T) A drilling effort in which an additional hole is drilled by leaving a previously drilled hole at some depth below the surface and above the total depth. A whipstock is set in the previously drilled hole which is the starting point for the sidetracking operation. This section of new hole is directionally drilled to a new objective bottom hole location (target). (Bul 12A)