Publications

PT Pertamina Hulu Energi Offshore North West Java (PHE ONWJ) field has been in operation for 45 years and is located offshore north of West Java Island with an area of 8,300 square km. PHE ONWJ has more than 2125 km of subsea pipelines and segmented to 437 individual pipeline. To maintain pipeline reliability and defined pipeline priority for inspection, maintenance and repair (IMR), pipeline risk assessments were conducted by internal and external parties using several different methodologies. For a better understanding of the Risk Assessment result, each methodology should be compared. The sensitivity analyses should also be reviewed to determine the main contributor to the risk condition. Sensitivity is the effect of changes in any variable on changes in the risk results. The most common subsea Pipeline Risk Assessment Methodology used by PHE ONWJ is Muhlbauer 2004, Muhlbauer 2015 and Risk-Based Inspection. This study evaluated five oil and gas subsea pipeline segments. In general, there are two objectives: first, comparing risk results among the Risk Assessment Methodologies applied; second is comparing the sensitivity. The risk assessment methodologies are translated into a mathematical model and computed in Monte Carlo-based simulation software. The risk value result shows that in high and medium-risk pipeline segments, all methodologies are valid with a 16% deviation from the maximum range. The sensitivity analysis result shows that the Muhlbauer 2004 methodology is sensitive to the internal fluid sample data, In-Line Inspection (ILI) result, coupon analysis, and riser condition. The Muhlbauer 2015 methodology is sensitive to internal corrosion, external corrosion, and geohazards. The Risk-based inspection methodology is sensitive to intrinsic damage mechanisms. The comparison and sensitivity data can be adopted to develop a more sensitive subsea oil and gas pipeline risk assessment methodology to enhance reliability analysis at PHE ONWJ.