Offshore Drilling Experience with Dual Derrick Operations

摘要

Smedvig took delivery of the fully class 3 dynamic positioned new generation drilling units West Navion and West Venture in Fegruary 2000. Both are equipped with full capacity dual Ramrigs with the dapability of running two strings in the water simultaneously. In a single well application the advantage lies in using the dual system for parallel making and breaking bottomhole assemblies, tool strings and pipestands and in running casing/BOP in parallel with drilling top hole. In a multiwell subsea template situation there is an additional potential in performing simultaneous in-water opeerations. While the main rig is in a BOP/riser drilling mode, the auxiliary rig can drill tophole and install surface casings in the next well. With proper planning, this could imply subsequent moving the BOP to the next well without having to come back to surface. In later phases the Xmas tree or other modules may be installed in other slots/positions in parallel with the main activity. The paper describes enhancement of drilling operations through a selection of cases that are experienced and proves that utilisation of the dual activity feature leads to a paradigm shift in drilling and completion operations.