DESIGN AND UPENDING ANBALYSIS OF FOUR LEG JACKET PLATFORM STRUCTURE ON THE NATUNA SEA

• Main Author: Noor Yuliansyah, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43188
• Institution: Institut Teknologi Bandung

Offshore platform is one of the offshore facilities that support oil and gas exploration, exploitation, and production activities. When the structure operating, it will bear the load either from the operating equipment or environment. Remembering the circumstance, it is exceptionally important to analyze the strength of the structure in terms of bearing the load. Several structures analysis which always performed over offshore platforms is in-place analysis, seismic analysis, and fatigue analysis. Some of the parameters that represent the strength of the structure and will be assessed during the analysis are member UC, Joint UC, and pile axial capacity. Not limited to those parameters, deflection and service life of the structure also assessed in the process. During the installation process, the structure will go through upending process hence in the process of offshore structure planning, it is necessary to upending analysis over the structure to prevent the failure when the upending process takes place. Upending with controlled flooding method use buoyancy tank to provide the upending force, then simulated through Flotation and Upending SACS 5.7. Results from in place analysis has to satisfy the following criteria, actual stress < allowable stress, both on the member and the joint. In the software is defined in terms of unity check (UC) < 1. Results from in place analysis operating condition, obtained maximum UC member was 0.95 and storm condition has 0.86 for maximum UC member. In addition, the maximum UC joint punching shear from operating condition was 0.499 at operating condition. Results from seismic analysis, obtained maximum UC member was 0.65 at DLE condition, the maximum UC joint punching shear from DLE condition was 0.288. From in-place and seismic analysis, obtained the value of deflection and pile safety factor number that had fulfill the requirements of SNI – 03 – 1729 – 2000 dan API RP2A WSD. Fatigue analysis result declared the entire member connections has a service life more than 20 years. Results from upending analysis, the scenario does not meet the minimum stability and mudline clearance criteria of Noble Denton 0028/ND. Therefore, the structure has fulfilled all criteria.