WAVE IN DECK ANALYSIS OF JACK UP PLATFORM MOPU DUE TO SUBSIDENCE
As more offshore platforms reach its end life, subsidence became an increasingly important problem. Such phenomenon, which mainly occurs due to reservoir compaction, permits the occurence of wave in deck loading that became a notable concern in assessing the integrity of fixed offshore platforms....
Saved in:
| Main Author: | |
|---|---|
| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/69751 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | As more offshore platforms reach its end life, subsidence became an increasingly
important problem. Such phenomenon, which mainly occurs due to reservoir
compaction, permits the occurence of wave in deck loading that became a notable
concern in assessing the integrity of fixed offshore platforms.
This study is focused on a jackup type Mobile Offshore Production Unit (MOPU)
which consists of shell plated hull, tubular steel legs, and mudmat foundation. The
generation of the finite element model comes naturally and is presented consisting
of the detailed geomtery and mesh manipulation in order to obtain an acceptable
model.
Three scenarios are included in this study with concurently decreasing airgap and
thus increasing the wave in deck inundation to the hull. Scenario 1 will not have
any wave in deck occurence as it is assessed in positive airgap scenario, instead,
the goal of scenario 1 is to propose steel strenghtening of the structure. Scenarios
that involve wave in deck, i.e., scenario 2 and 3 were each subjected into different
wave in deck loading calculation method.
Wave in deck calculation method that are compared in this study is API, MSL,
and BE method. Since BE method is only applicable when the bottom of steel of
the hull is below still water level, which only occurs in scenario 3, scenario 2 will
only compare API and MSL method while scenario 3 will compare all three.
The comparison basis of different wave in deck methods in this thesis includes
stress, vertical plate deflection, and stability analysis of the MOPU. The latter was
examined in its bearing, sliding, and overturning capacity. Result shows that the
MSL method consistently produce the most conservative result, followed by API
and BE method. Additional conclusion include combination of the methods is
necessary to yield a better result and represent accurate wave in deck phenomenon
accordingly.
|
|---|