OFFSHORE OIL-DRILLING RIG AND METHODS FOR INSTALLING SAME ON AN OFFSHORE OIL-DRILLING SITE

摘要

The invention concerns an offshore oil-drilling rig, of the type comprising a deck (1) mounted mobile on legs (2) each including a support base (8) on the seafloor and a pontoon (10) open at its base and designed to penetrate into the seafloor. Each pontoon (10) is arranged inside the leg (2) and is mobile in the axis of said led (2) between a retracted upper position and a projecting lower position and anchored on the seafloor. The invention also concerns methods for installing such a rig on an oil-drilling site.