SINGLE BORE RISER SYSTEM

摘要

A single bore riser (12) system is disclosed which is based on a dual bore completion tree (16). An eccentric offset sub (14) is coupled to the top of the tree (16) and which can be sealed by BOP pipe rams. The completion tree (16) has a main bore (18) and an auxiliary bore (20) with ball valves (22, 24) located in the respective bores. A remotely actuatable annulus plug (28) is located in the bottom of the annulus bore (2) and is moveable between a first position allowing fluid flow through the annulus bore (2) and a second position sealing the annulus bore (2) to provide control of various operations. Embodiments of the invention are described.