WELL HEAD SEALING DEVICE Russian patent published in 2006 - IPC E21B33/03 

FIELD: well head sealing device used during drilling string trip operation and drilling string rotation with kelly stem.

SUBSTANCE: device comprises hollow cylindrical body with upper and lower flanges provided with borings. Body also has central through channels for stem with production equipment receiving. Device also has rotor installed in the body and supported by rotary supports. The rotor comprises sealing member and connection members to connect sealing member with rotor. The connection members are formed as upper and lower bushes cooperating with rotary supports and the borings. Device comprises hydraulic working chamber made as annular cavity between the body and sealing member and filled with working agent. Control unit, which regulates force of sealing member pressing to stem, is hydraulically connected with working hydraulic chamber. Device is provided with hydraulic channels and pressure equalizing unit, which equalizes pressure between hydraulic working chamber and well bore. The equalizing unit is installed on body between the flanges and is formed as hydraulic cylinder with spring-loaded piston, which divides the hydraulic cylinder into two cavities. One cavity is hydraulically connected with hydraulic working chamber. Another cavity is hydraulically connected with shutoff valve and through orifice. The through orifice is formed in lower flange and extends from outer surface to the boring. Control unit is made as hydraulic cylinder provided with piston. The piston has displacement mechanism made as screw drive. The sealing member is formed of two coaxial members, namely outer annular diaphragm and inner replaceable seal. The borings have sealing members cooperating with upper and lower rotor bushes.

EFFECT: reduced labor inputs, increased operational reliability and simplified structure.

1 dwg