Drill String Circulation Apparatus

A method of sealing around a drill string to enable controlled fluid circulation in a borehole, while retaining the ability of the drill string to be reciprocated and rotated within said borehole, comprising the steps of:

• a) providing an apparatus comprising:
• a sleeve member comprising an elongated tubular body with a longitudinal bore therethrough, said sleeve member comprising an outer diameter suitable for being sealingly gripped by a blowout preventer;
• and
• a drill string having an outer diameter sized to fit within said sleeve member bore, said drill string comprising one or more seals disposed on an exterior surface thereof, said seals sized to create a seal between said sleeve member and said drill string, when said drill string and said one or more seals are positioned within said sleeve member bore, while said drill string is still capable of movement within said sleeve member when said seals are within said sleeve member bore;
• b) positioning said apparatus in a blowout preventer assembly comprising two or more annular blowout preventers, such that said sleeve member is positioned within and sealingly gripped by the uppermost of said two or more annular blowout preventers;
• c) sealingly gripping said sleeve member with said uppermost annular blowout preventer;
• and
• d) positioning said drill string so that two or more seals are positioned within said bore of said sleeve member.

A wellbore assembly, comprising:

• a blowout preventer assembly comprising a plurality of blowout preventers having an uppermost blowout preventer;
• a sleeve member sealingly gripped in said uppermost blowout preventer, said sleeve member comprising an elongated tubular body with a longitudinal bore therethrough and having enlarged outer diameter sections proximal the upper and lower ends thereof, said sleeve member further comprising one or more pressure relief passages in said enlarged outer diameter section proximal said lower end;
• and
• a drill string having an outer diameter sized to fit within said sleeve member bore, said drill string comprising a plurality of seals disposed on an exterior surface thereof, said seals sized to create a seal in said bore of said sleeve member between said sleeve member and said drill string, said drill string and two or more of said plurality of seals positioned within said sleeve member bore.