Enabling Formal Safety Assessment Method in Jack-Up Rig Operations

Abstract

Since the inception of jack-up rig operations in the early 1950s, series of hazardous accidents has been witnessed, and losses recorded. These events are approximated to occur at least twice in a year. With this statistics, the harsh offshore environment demands jack-ups of premium quality. Designing a premium self-elevating (jack-up) offshore structure is one that must be founded on well-proven principles, industry-accepted reliability techniques and criteria. Construction must also follow a suitable classification society’s guidelines for the different aspects and phases of the jack-up.Before designing and constructing a jack-up which can optimally operate within the harsh offshore environment, identifying the hazards associated with the structure in this environment and how to mitigate or manage them is essential. The Formal Safety Assessment (FSA) is the methodology employed in the maritime industry to identify and check these marine hazards, and to design ways to bring them under control in a cost effective manner. The five steps in FSA are hazard identification, risk assessment, risk control option, cost benefit analysis/assessment, and decision making steps. In this paper, the jack-up rig was introduced and its operation principle explained from the transit mode to the operation mode offshore. The hazards associated with self-elevating units were identified using the Preliminary Hazard Analysis (PHA). The Capsizing Hazard which was identified as critical was considered and analyzed using the Fault Tree Analysis (FTA). Consequently, the Fishbone Diagram was used to analyze, state the root cause of capsizing of jack-up structures through the risk factors of sampled incident cases, and recommend measures to curb the special problem. Some recommended measures are a bolster of existing guidance. Recommendations and improvements on how to eliminate or reduce capsizing of jack-ups through early design and construction, and before in-service operation were made.