Design of jacket lifting and hang-off point for the Seesaw barge jacket removal concept

Design of jacket lifting and hang-off point for the Seesaw barge jacket removal concept

Böcker, B.M.

Massie, W.W. (mentor)
De Waard, O.L. (mentor)
Vrijling, J.K. (mentor)
Wardenier, J. (mentor)

Civil Engineering and Geosciences

Hydraulic Engineering

2001-11-30

The first platforms for oil and gas production in the North Sea have been installed around 1970. Since then about 500 platforms have been built to explore the North Sea oil and gas fields. Now, after 30 years of use, the first platforms are abandoned, creating a demand for innovative and economical removal concepts. Heerema Marine Contractors (HMC), considered to be the world market leader in the installation and transport of offshore platforms, has developed the Seesaw barge jacket removal concept. The jacket is lifted in one section or in the largest section possible (by the SSCV 'Thialf') and tilted onto a barge (the H-851-barge) in this concept. The rotation of the jacket during the removal procedure reflects the seesaw principle. Previous studies at HMC proved the Seesaw barge concept to be feasible for the removal of typical North Sea jackets. The Seesaw barge removal concept combines the capabilities and capacities of existing HMC equipment. An important aspect of the Seesaw removal barge concept is the optimal use of the jacket buoyancy during the removal procedure by submerging the stern of the H-851 barge. Other advantages are the minimum amount of sub sea operations and the possibility to re-use the jackets. The Seesaw barge removal concept consists of four phases. 1. Upending of the Extended Tilting Beams (ETB' s) 2. Mating and load transfer of the jacket 3. Rotation of jacket onto H-851 barge 4. Transportation on the barge Objectives ofthe thesis study • The primary objective of the thesis study is to design a lifting and hang-off system, compatible with the jacket configuration and strength, for jackets, that will be removed with the Seesaw barge removal concept • The secondary objective is to make the lifting and hang-off system re-usable or adjustable for jackets with different dimensions and structural configurations.

seesaw barge
jacket lifting
offshore structures

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Student theses

master thesis

(c) 2001 Böcker, B.M.