Response of a Semi-sub Platform to Environmental Load

The increasing usage of floating platforms such as semi-submersibles in the exploration and production of oil & gas has increase the number of research on floating platforms. One of the important researches is to investigate and predict the movement of floating platforms caused by environment...

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Bibliographic Details
Main Author: Mohd Faiz Bin Mohd Yaacob, Mohd Faiz
Format: Final Year Project
Language:English
Published: Universiti Teknologi Petronas 2010
Subjects:
Online Access:http://utpedia.utp.edu.my/1013/1/0001.pdf
http://utpedia.utp.edu.my/1013/
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Summary:The increasing usage of floating platforms such as semi-submersibles in the exploration and production of oil & gas has increase the number of research on floating platforms. One of the important researches is to investigate and predict the movement of floating platforms caused by environmental loads. One of the major components in the design of a semi-submersible platform is to predict its motion response due to waves. Nowadays, engineers have computer software to do the calculation and simulation to predict the response of a floating structure. Not many would do an experiment to compare and see if there is any agreement between the computer analysis value and the experimental value. So from this research, exclusive experimental value will be achieved and a comparison can be made between computer analysis value and experimental value. Later these results can and will contribute to the designs of future semi-submersibles platform. This research will be based on real life model testing of a scaled down semi-submersible platform. The model was based on a prototype semi-submersible platform design for Malaysian waters by a group of students from a foreign university. The study targets to fill a vacuum in the design of such important structures by conducting physical modelling. Changing the wave height, wave period, and ballast conditions, a series of laboratory tests was achieved at 20 mx 10 mx 1.2 m wave basin of the Coastal Engineering Laboratory, Universiti Teknologi PETRONAS, under regular waves and random waves while the semi-submersible is moored by 16 mooring lines connected to the basin floor. The dynamic response of the semi-submersible was monitored by photographic methods and the heave, surge and pitch of the structure were plotted vs. time. The analysis of the maximum responses showed the significance of the wave period and ballast condition. The scale modelling data show a satisfactory similarity with the prototype. An equation of motion for heave motion was also constructed and it can be applied to predict the motion response of the semi-submersible. A force test was also conducted to get the value of force from wave and current towards the semisubmersible model. The force calibration result can later be applied to compare theoretical force calculation with experimental values.