Offshore platform

Abstract

Offshore platform comprising a bottom structure ( 1 ) comprising a polygonal base ( 5 ) resting on the sea floor ( 2 ) having suction piles ( 10 ) joined to its corners and a first support frame ( 8 ) connected to the polygonal base ( 5 ) including interconnected open-ended pipes ( 15 ), conductors ( 33 ) extending from above the water surface ( 36 ) into the seabed through the open-ended pipes ( 15 ) of the first support frame ( 8 ), and at least one further support frame ( 22, 24 ) including interconnected open-ended pipes ( 25 ) extending around the conductors ( 33 ), wherein each further support frame ( 22, 24 ) is secured to the conductors ( 33 ) at a predetermined level.

We claim:  
     
         1 . A method of installing an offshore platform on a sea floor, which method comprises the steps of: 
 (a) providing the sea floor with a set of releasably interconnected support frames comprising a bottom structure including a polygonal base having suction piles joined to its corners and a first support frame connected to the polygonal base including interconnected open-ended pipes that are arranged perpendicular to the base, and at least one further support frame, wherein each further support frame includes interconnected open-ended pipes and has the same cross-section as the first support frame, and wherein the suction piles are fixed in the seabed;    (b) lowering conductors into the seabed to a predetermined depth through open-ended passages formed by the open-ended pipes of the at least one further support frame and the first support frame such that the upper ends of the conductors extend to above the water surface; and    (c) lifting the at least one further support frame to a predetermined level and securing the at least one further support frame to the conductors.    
     
     
         2 . The method according to  claim 1 , wherein step (a) comprises lowering to the sea floor the bottom structure; allowing the suction piles to enter into the seabed; and lowering the at least one further support frame to the bottom structure so as to form the set of interconnected support frames.  
     
     
         3 . The method according to  claim 1 , wherein step (a) comprises lowering to the sea floor the set of releasably interconnected support frames comprising the bottom structure and the at least one further support frame; and allowing the suction piles to enter into the seabed.  
     
     
         4 . The method according to  claim 1 , wherein the set of releasably interconnected support frames comprises at least two further support frames.  
     
     
         5 . The method according to  claim 1 , wherein the uppermost further support frame is provided with a platform deck.  
     
     
         6 . An offshore platform comprising a bottom structure comprising a polygonal base resting on the sea floor having suction piles joined to its corners and fixed in the seabed and a first support frame connected to the polygonal base including interconnected open-ended pipes that are arranged perpendicular to the base, conductors extending from above the water surface into the seabed through the open-ended pipes of the first support frame, and at least one further support frame having the same cross-section as the first support frame and including interconnected open-ended pipes extending around the conductors, wherein each further support frame is secured to if the conductors at a predetermined level.  
     
     
         7 . The offshore platform according to  claim 6 , comprising at least two further support frames.  
     
     
         8 . The offshore platform according to  claim 6 , wherein the uppermost further support frame is provided with a platform deck.