Patent ID: 7762744

Claim:
A method for removing an offshore jacket structure ( 15 ) standing on the seabed ( 16 ) in a body of water, said method comprising the steps of: (a) providing a ballastable seagoing vessel ( 1 ) having a generally float-like main buoyancy section ( 2 ) being generally planar and being generally horizontal in the normal floating condition of the vessel ( 1 ) and having two elongate auxiliary buoyancy sections ( 3 ) protruding above and on either side of the main buoyancy section ( 2 ) in said normal floating condition; (b) bringing said vessel ( 1 ) into the vicinity of the jacket structure ( 15 ); (c) ballasting the vessel ( 1 ) so that the entire vessel is at first rotated less than 90° from the horizontal, next it is lowered so that a lower end ( 11 ) of the vessel rests on the seabed ( 16 ) adjacent to the jacket structure ( 15 ), and whereupon the vessel is rotated beyond 90° to bring the main section ( 2 ) into contact with the jacket structure ( 15 ) while its lower end ( 11 ) is in contact with the seabed ( 16 ); the auxiliary buoyancy sections ( 3 ) now being located on opposite sides of the jacket structure; (d) securing the vessel ( 1 ) to the jacket structure ( 15 ) and deballasting the auxiliary sections to rotate the vessel with the jacket structure, and further de-ballasting the vessel so as to raise the vessel with the jacket structure to the water surface ( 17 ) while rotating the vessel so that the main section assumes the generally horizontal position.