2019 : Risk Assessment of Subsea Gas Pipeline Due to Port Development Located at Narrow Channel

Prof.Dr.Ir. Ketut Buda Artana ST., M.Sc.

A.A. BGS. Dinariyana Dwi Putranta S.T., MES, Ph.D

Dr. Dhimas Widhi Handani ST.,M.Sc

Abstract

Background and Objective: Offshore gas pipeline is one of the methods to distribute gas from gas field to receiving facility. There is 16" subsea export gas pipeline exporting gas from Poleng gas field to ORF (Onshore Receiving Facility) in Gresik. Due to plan of port development in Socah-Bangkalan, the pipeline segment located in KP 49-55 could be eventually affected by the development plan both during construction of the port and during its operation. This study aimed to assess the risk possessed by the export gas pipeline due to port development plan during the construction and operation period. Materials and Methods: The ranks of frequency and consequences were mapped into risk matrix according to DNV-RP-F107. The mitigation was selected by implementing Multiple Attribute Decision Making (MADM) approach using Analytical Hierarchy Process (AHP) method. Results: Based on the result, during construction period, risk profiles laid in acceptable and ALARP regions. These mean that technically in practical, the risk still acceptable and no further mitigation was required for hazard possess by the pipeline in acceptable and ALARP regions. During operation of Jetty, the risk to pipeline was unacceptable, except for hazard of dropped and dragged anchor caused by the tugboat. The most preferable pipeline risk mitigation method was lowering the pipeline segment located in front of the jetty to 2 m below the water depth of final capacity development of port and installing additional of navigational aid (yellow buoy) to indicate the existence of the pipeline. Conclusion: Therefore, the risk assessment should be taken for every activity that …