Method for enhanced redeployability of hyjack platforms
First Claim
1. A method for redeploying an offshore platform structure from a first site to a second site of different water depth, comprising:
- releasing the connection between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site, said releasing comprising cutting through a plurality of pile sleeves and the piles locked therein to remove pile-to-pile sleeve connections in an extended first stage of the pile sleeves;
vertically raising the offshore platform structure by pumping air into a plurality of the tank members, each being an elongated cylinder vertically aligned in load bearing relationship with underneath a discrete contact point of the subsea rig support interface corresponding to the to the footprint of a jack-up rig;
resizing a surface tower supported upon subsea jacket base while the jacket base is vertically raised;
towing the offshore platform structure to the second site;
vertically lowering the offshore structure by ballasting the tank member;
installing the platform at the second site with the surface tower above the ocean surface and a subsea rig support interface presented within the depth capability of a jack-up rig.
1 Assignment
0 Petitions
Accused Products
Abstract
A method is disclosed for redeploying an offshore platform structure from a first site to a second sight of different water depth in which the connection is released between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site. The offshore platform structure is vertically raised by pumping air into a tank member at the top of the subsea jacket base and the surface tower which is supported upon subsea jacket base is reworked while the jacket base is vertically raised. This operation is less difficult than attempting operations offshore on a horizontally disposed surface tower. The offshore platform structure is transported to the second site and the tank member is ballasted to vertically lower the offshore platform to the second site where it is installed.
74 Citations
10 Claims
-
1. A method for redeploying an offshore platform structure from a first site to a second site of different water depth, comprising:
-
releasing the connection between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site, said releasing comprising cutting through a plurality of pile sleeves and the piles locked therein to remove pile-to-pile sleeve connections in an extended first stage of the pile sleeves; vertically raising the offshore platform structure by pumping air into a plurality of the tank members, each being an elongated cylinder vertically aligned in load bearing relationship with underneath a discrete contact point of the subsea rig support interface corresponding to the to the footprint of a jack-up rig; resizing a surface tower supported upon subsea jacket base while the jacket base is vertically raised; towing the offshore platform structure to the second site; vertically lowering the offshore structure by ballasting the tank member; installing the platform at the second site with the surface tower above the ocean surface and a subsea rig support interface presented within the depth capability of a jack-up rig.
-
-
2. A method for redeploying an offshore platform structure from a first site to a second site of different water depth, comprising:
-
releasing the connection between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site; vertically raising the offshore platform structure by pumping air into a tank member at the top of the subsea jacket base; resizing a surface tower supported upon subsea jacket base while the jacket base is vertically raised; towing the offshore platform structure to the second site; vertically lowering the offshore structure by ballasting the tank member; installing the platform at the second site with the surface tower above the ocean surface and a subsea rig support interface presented within the depth capability of a jack-up rig. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
-
Specification