Patent ID: 6581692
Filing Date: 2003-06-24
Classification: E21B

Abstract:
An apparatus for connecting and disconnecting tubulars and a tubing string suspended in a well and for axially displacing that tubing string, comprising:a suspension structure; a top end connecting unit including at least one connector for connection to a tubular axially projecting from said at least one connector, and at least one main high pressure conduit communicating with said at least one connector for providing circulation through a tubular connected to said at least one connector; a connecting shell bounding a connecting chamber, said connecting shell having an upper passage and a lower passage for receiving tubulars, means for sealing off said passages against tubulars extending through said passages, a preventer for separating an upper portion of said connecting chamber from a lower portion of said connecting chamber, and a back-up high pressure conduit communicating with said lower portion of said connecting chamber; a first engagement structure for engaging a tubular projecting from above into said upper portion of said connecting chamber, said first engagement structure being carried by said suspension structure; and a second engagement structure for engaging a tubular projecting from below into said lower portion of said connecting chamber; wherein at least said top end connecting unit is movable up and down relative to said suspension structure; and said connecting shell is located below said top end connecting unit; characterized by a pressure compensating structure for compensating axial force exerted by pressure in said upper portion of said connecting chamber pressing a tubular projecting from said upper portion of said connecting chamber in an axial direction out of said connecting chamber, said pressure compensating structure including at least one pressure chamber and at least one pressure transfer member formed by the connector or by a separate pressure transfer member connectable to a tubular; said pressure chamber having a passage and means for sealing off said passage against said at least one pressure transfer member, said at least one pressure chamber being connected to said connecting chamber for maintaining a pressure in said at least one pressure chamber corresponding to pressure in at least said upper portion of said connecting chamber, and said at least one pressure transfer member being displaceable in said at least one pressure chamber and arranged for transferring a force axially pressing the tubular into said connecting chamber in reaction to pressure in said at least one pressure chamber.