Risk Assessment of Subsea Pipeline of Natural Gas in The Cross Area: Case Study in West Java Waters

Abstract

The Risk assessment for 20 inches’ pipeline of the Natural Gas from the Floating Storage Regasification Unit (FSRU) to the landing point which has long about 14 km is made due to the crossing pipes between existing and incoming pipe which has effect to ship activity of the Patimban Port and Operations Office (KSOP) working area. The depth of water in the assessed pipeline varies in the range of 0-16 m, from the outermost coastline 14 km to the FSRU. After the subsea pipeline installation, the area becomes a restricted/restricted zone so that only ships from existing and incoming who can operate in the area. The risk assessment of this gas pipeline is based on the assumption of the worst-case by ships operating around the pipeline. Assumed also that ships with the largest and heaviest anchors in each group of ships will drop and pull anchors so there is a risk of the existence of this gas pipeline. In the area of pipe crossing, the risk assessment will be carried out on the stability of the pipe stretch and land subsidence. The risk assessment methodology on this gas pipeline is carried out using Det Norske Veritas – recommended practice - F107 risk assessment of pipeline (DNV-RP-F107) as a reference. The frequency and consequences of several conditions and groups of ships are analyzed which will produce the level of risk, presented in the form of a risk assessment matrix to describe three risks as dropped anchor, dragged anchor and sinking ships also possibility impact of the damage. The results of the risk assessment become a reference for mitigation making and recommendations needed to improve the level of risk and impact of each case, therefore it can be ensured for all conditions do not have values that endanger the pipeline.