Drilling derrick for offshore drilling incorporating a stressed-skin and offshore platform

Abstract

A drilling derrick ( 1 ) for offshore drilling operations arranged to be a protecting enclosure ( 3 ) accommodating a drill pipe device adapted to perform drilling operations and allowing a pipe section to be moved to and from the drilling derrick ( 1 ), the drilling derrick ( 1 ) accommodating a pipe racking structure for stacking and retaining pipe sections for use in drilling operations, the drilling derrick ( 1 ) is adapted to be mounted on a deck ( 2 ). The drilling derrick ( 1 ) comprising a stressed-skin structure having external load carrying panels ( 3 ). The invention also relates to an offshore platform comprising at least one drilling derrick ( 1 ).

1 . A drilling derrick for offshore drilling operations arranged to be a protecting enclosure accommodating a drill pipe device adapted to perform drilling operations and allowing a pipe section to be moved in and out of the drilling derrick, the drilling derrick accommodating a pipe racking structure for stacking and retaining pipe sections for use in drilling operations, the drilling derrick is adapted to be mounted on a deck, characterised in that the drilling derrick comprising comprises a stressed-skin structure having external load carrying panels. 
     
     
         2 . The drilling derrick according to  claim 1 , characterised in that the external load carrying panels are external stiffened panels comprising of outer plating skins reinforced by inner vertical stiffeners and inner horizontal rib members in a substantially rectangular pattern, wherein the stressed-skin structure will provide the support load carrying structure for loads acting on the drilling derrick. 
     
     
         3 . The drilling derrick according to  claim 1 , characterised in that the external load carrying panels are external corrugated panels comprising of corrugated plates having vertical corrugations and horizontal rib members, wherein the stressed-skin structure will provide the support load carrying structure for loads acting on the drilling derrick. 
     
     
         4 . The drilling derrick according to  claim 1 , characterised in that the drilling derrick comprising closable openings. 
     
     
         5 . The drilling derrick according to  claim 1 , characterised in that the drilling derrick is positioned upon the deck on an offshore platform. 
     
     
         6 . The drilling derrick according to  claim 1 , characterised in that the drilling derrick has a substantially rectangular horizontal cross section. 
     
     
         7 . The drilling derrick according to  claim 6 , characterised in that the substantially rectangular horizontal cross section of the drilling derrick vary in size over the height of the drilling derrick, from a bottom part of the drilling derrick supported on the deck to a top part of the drilling derrick. 
     
     
         8 . The drilling derrick according to  claim 7 , characterised in that the cross section of the top part of the drilling derrick is smaller than the cross section of the bottom part of the drilling derrick. 
     
     
         9 . The drilling derrick according to  claim 6 , characterised in that corners of the drilling derrick are rounded. 
     
     
         10 . The drilling derrick according to  claim 1 , characterised in that the drilling derrick has a substantially round or elliptical horizontal cross section. 
     
     
         11 . The drilling derrick according to  claim 10 , characterised in that the substantially round or elliptical horizontal cross section of the drilling derrick vary in size over the height of the drilling derrick, from a bottom part of the drilling derrick supported on the deck to a top part of the drilling derrick. 
     
     
         12 . The drilling derrick according to  claim 11 , characterised in that the cross section of the top part of the drilling derrick is smaller than the cross section of the bottom part of the drilling derrick. 
     
     
         13 . The drilling derrick according to  claim 1 , characterised in that the drilling derrick comprises outward extending stiffened panels at a lower part of the drilling derrick where a cross section surface of the lower part is at least 50 percent larger than the largest cross section surface of the upper part of the drilling derrick, such that a larger enclosed area above the deck is provided. 
     
     
         14 . The drilling derrick according to  claim 13 , characterised in that the lower part of the drilling derrick is arranged to correspond with structures below the deck. 
     
     
         15 . The drilling derrick according to  claim 1 , characterised in that a raised drill floor is arranged and integrated in the drilling derrick above the deck. 
     
     
         16 . Offshore platform comprising at least one drilling derrick according to  claim 1 .