DESIGN AND CROSSING SUBSEA PIPELINES ANALYSIS AT MADURA STRAIT USING CONCRETE SLEEPER AS SUPPORT

• Main Author: Gunawan, Jeremy
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/57043
• Institution: Institut Teknologi Bandung

80% of this world consume oil and gas energy. Because of highly demand of oil and gases, exploration for oil and gas is needed. Subsea pipeline is a facility used for supporting oil and gas exploration. Before pipeline is used for exploration, it is necessary to design and analysis for the pipeline. The first step in designing pipelines is analysing wall thickness using DNVGL-ST-F101. In this standard, wall thickness is designed to withstand Internal Pressure Containment Collapse, External Over Pressure Collapse, Propagation Buckling Collapse, and Combined loading criteria failure. After the wall thickness is selected, on bottom stability analysis is performed using DNV-RP-F109 codes to check if pipeline is stable at seabed in vertical or lateral direction. Installation analysis is performed using OFFPIPE software to check the configuration of roller, tensioner, and stinger so it will not exceed maximum stress criteria. Pipelines will not be installed perfectly because of the seabed morphology. Sometimes any spans will happen. Free span analysis is then performed to check allowable free span during pipelines installation until operations using DNV-RP-F105 codes. Pipelines is designed to pass screening fatigue criteria. In installation process, sometimes another hazard is already on the selected route for example existing pipelines. To do the crossing pipelines, support like concrete sleeper is needed. The support structures are needed to pass the stability structure criteria, like ultimate bearing capacity, sliding, dan overturning. The structure installation will make settlement so it must be checked wether the support height meets the minimum crossing criteria after consolidation settlement happened. A support structure forced pipelines to bend so stress analysis must be performed using software CAESAR II using ASME B31.8 Chapter VIII design codes. The design has been performed using pipelines with 273.05 ???????? outer diameter, the selected wall thickness is 12.7 ???????? or 0.5 ????n, with concrete coating thickness 40 mm and allowable free span 14.9 m. Installation analysis has been performed and meet the stress criteria using configuration of 1° trim and 3° hitch. Concrete sleepers have been designed and have met stability criteria for support structure and meet the stress criteria after checked using ASME B31.8 Chapter VIII design Codes.