The majority of existing fire and explosion consequence models currently used in the offshore LNG process facilities focus on modelling individual accidental hazard. However, such undesired events can occur simultaneously leading to multiple consequences. This study focuses on developing a model-based Bayesian network (BN) approach to envisage the most probable accidental scenario in complex offshore process facilities by considering the evidence of primary causes. The proposed methodology comprises of evolving scenario identification, accident consequence framework development, accident scenario likelihood estimation, and ranking of the scenarios. The approach was tested and demonstrated with a case study for an offshore LNG process facility (Floating LNG). The developed methodology using the BN approach was found to be effective in determining the most credible accidental scenario.
Offshore process operation is a highly complex system due to its varied equipment, control and process activity. Floating Liquefied Natural Gas (FLNG) is the most recent addition to floating process facilities and is dynamic in nature and can be characterized by complex subsystems, distributed processes, uncertainty and a high degree of automation. Chemicals or hydrocarbon release from these facilities can escalate to catastrophic events which may result in casualties and significant damages to the environment and coastal marine ecosystems (HSE, 1996). The production of hydrocarbons in the offshore process industry has the potential for events involving major fires and/or explosions (Krueger and Smith, 2003). This is reflected in examples of several offshore accidents, such as the 1988 Piper Alpha incident in the UK North Sea (Pate-Cornell, 1993), capsizing and sinking of the Petrobras P-36 in Roncador, Brazil (Atherton and Gil, 2010), explosion on the Cidade de Sao Mateus (PGJ, 2015), and fire on the Pemex Abkatun Alpha platform in the Gulf of the Mexico (Turner-Neal, 2015). According to Pate-Cornell (1993), the Piper Alpha tragedy caused 165 deaths due to an explosion after releasing of hydrocarbons. Atherton and Gil (2010) reported on series of explosion that had occurred in the Petrobras P-36 platform claiming 11 lives and a loss of up to $1 billion a year (Keep, 2001). Recent explosion on Floating Production Storage and Offloading (FPSO) unit of Cidade de Sao Mateus caused 5 deaths and 4 missing crews. According to the Pemex press release, a fire outbreak in the Abkatun Alpha platform killed 4 people and injured as many as 16 others.