4 LEGS OFFSHORE PLATFORM DESIGN AND ON-BOTTOM STABILITY ANALYSIS ON RIG TO REEF JACKET MODULE

• Main Author: Denzar Syah Aldebaran, Mohammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86440
• Institution: Institut Teknologi Bandung

Indonesia is a country rich in crude oil, with more than 600 offshore oil and gas platforms scattered across Indonesian seas. However, over 100 platforms have ceased operations. In this study, a model of an offshore platform structure is created to undergo in-service analysis as well as on-bottom stability analysis. After the platform meets in-service conditions and has ceased operations, it will undergo a decommissioning process. Decommissioning is the process of repurposing the platform to ensure that the non-operational platform does not pose potential hazards to the surrounding environment. The decommissioning method used in this study is toppling, where the platform’s jacket will be placed in a horizontal position on the seabed at the final stage to serve as an artificial reef, commonly referred to as 'rig-to-reef'. For a jacket transformed into an artificial reef, there are several recommended limitations that must be met to ensure that the jacket does not pose a hazard to human activity in the surrounding area. These limitations include maintaining a clearance from MSL of 26 meters, placing a navigational buoy on top of the jacket, and registering the artificial reef on international maritime navigation maps. Therefore, it must be ensured that the jacket does not shift location during its time as an artificial reef. This shift can be analysed through on-bottom stability analysis, which checks for failures such as sliding failure, caused by horizontal forces leading to displacement, and overturning failure, which causes the structure to rotate or tip over. The analysis will be conducted using structural modelling software, AutoCAD, and Microsoft Excel to obtain the safety factor values, which will refer to the API RP2A-WSD standard."