Patent ID: 7658228

Claim:
A marine riser system comprising a wellhead comprising a riser disconnect package to a lower riser package with a lower blowout preventer, said lower riser package being connected to a lower end of a high pressure riser ( 10 ) extending from said lower riser package to a near-surface blowout preventer stack ( 20 ) arranged near the sea surface ( 92 ), said near-surface blowout preventer stack ( 20 ) being connected to a lower end of a low pressure drilling riser ( 30 , 40 ) with a slip joint ( 80 ), said low pressure drilling riser ( 30 , 40 ) extending from said near-surface blowout preventer stack ( 20 ) up to near a drill floor ( 90 ) of a vessel ( 93 ), said riser system further comprising a high pressure extension sleeve ( 60 ) in said low pressure drilling riser ( 30 , 40 ) with a lower end ( 61 , 62 ) of said low pressure drilling riser ( 30 , 40 ) with a seal ( 61 ) being connected to a connector ( 25 ) on said near-surface blowout preventer ( 20 ), and a top end extending above said drill floor ( 90 ) and an upper end of said low pressure drilling riser ( 30 , 40 ), a workover blowout preventer with a wireline or coiled tubing interface ( 64 ) at an upper end of said high pressure sleeve ( 60 ), said high pressure sleeve ( 60 ) being arranged for hanging in a main block ( 70 ) during wireline or coiled tubing operations, said seal ( 61 ) being disconnectable from said connector ( 25 ) of said near-surface blowout preventer stack ( 20 ) so that said high pressure extension sleeve can be pulled up from said low pressure riser ( 30 , 40 ) after completion of wireline or coiled tubing operations.