PERFORMANCE ASSESSMENT OF CONVENTIONAL STEEL RISERGUARDS UNDER ACCIDENTAL IMPACT FOR OPERATIONS IN MALAYSIAN WATERS

The operation of offshore platforms largely depends on the support it receive from
offshore logistics, which come in the form ofoffshore support, service and supply
vessels. These vessels make frequent trips to offshore platforms depending on the
location, to provide essential supplies. Vessels approaching platforms for berthing
increases the risk of a potential accidental collision with platform risers. Risers are
overhanging pipelines which transport highly flammable oil and gas from the
reservoir below seabed to the processing facilities on the platform. In view of that,
platform operators in Malaysian waters have installed protective structures called
riser-guards to prevent accidental impact on risers by operating vessels. The
commissioning of riser-guards have resulted in several pre and post-installation
issues which demand further design improvisation or development of an alternative
protection system for risers. Prior to undertaking any design improvisation efforts,
the currently employed conventional steel riser-guard must be analysed and its
response to accidental impact must be studied. Lack of in-depth study and published
materials on the response of conventional steel riser-guard to accidental vessel
impact becomes the major motivation for undertaking this research. In this research,
dynamic analysis is performed using the well-established finite element analysis
methodology. The outcome ofthis dynamic analysis will be used to establish design
criteria which will serve as a baseline for engineers to design an alternative system
for the conventional steel riser-guard.