Dual bore riser

Abstract

A dual bore riser system is described which includes a conventional monobore riser (12) for production access and an independent coil tubing (14) disposed in parallel with the monobore riser (12) for providing annular access. The monobore riser includes discrete A joints of tubing, casing or drill pipe and the coil tubing riser may be any suitable size but is normally between 23/8" and 27/8" outside diameter. The standard monobore riser (12) and coil tubing riser (14) is fed from a coiled tubing reel (78), which is conventional, via a sheave (80) and straightening rollers into the well with the tubing riser. The coiled tubing is clamped to the tubing riser by clamps (16) at intervals along its length corresponding to a joint every 30 ft. The upper end of the landing spool adaptor (28) receives the tubing (14) and also contains a termination for the coiled tubing which is typically a swage device (32). The 5".times.2" landing spool adaptor (28) and landing spool (29) has an 18" outside diameter to fit into the BOP stack (42), and the landing spool (29) has a smooth outside surface for co-operating with the interior of the annular BOP.

Dependencies are inferred from the claim text.