SUBSEA PIPELINE DESIGN AND CROSSING ANALYSIS

• Main Author: Gloriani Putri - NIM 15514038 , Irene
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/28110
• Institution: Institut Teknologi Bandung

<p align="justify">The selection of subsea pipeline must have many considerations. One of it is to avoid crossing with existing pipeline which has already installed. Along with the increasing demand of oil and natural gas, the crossing of new and existing pipeline is inevitable. Pipeline is expected not to have crack, corrosion, and fatigue when it is installed on seabed. The design process of subsea pipeline refers to several design standards. The undertaken process is pipeline’s wall thickness, on bottom stability, installation analysis, and free span analysis. Wall thickness is determined by four criteria based on DNV-OS-F101 design standard. The highest number obtained becomes the wall thickness to prevent pipeline from internal corrosion. On-bottom stability will determine concrete coating thickness. This coating can help pipeline to remain stable on seabed. On-bottom stability refers to DNV-RP-F109. Furthermore, lay barge specification for pipe installation can be determined from installation analysis. Design is continued with free span analysis which refers to DNV-RP-F105. From this analysis will be obtained the allowed free span length. The entire design process is carried out under three conditions: installation, hydrotest, operation. In this thesis, the obtained free span length is 7.5 m and this value is used for crossing analysis. This analysis is also affected by the height of support structure. The stress obtained from crossing analysis will be checked to fulfill the allowed stress. Two models are designed which are four concrete mattress structures with one concrete sleeper structure and seven concrete sleeper structures. Both of these models have met the allowable stress.<p align="justify">