Operational risk analysis of blowout scenario in offshore drilling operation

Abstract

Offshore drilling is a complex and hazardous operation. The safety of the drilling operation is a strong function of many time-dependent parameters. The traditional risk analysis model fails to capture the impact of spatial and temporal variations of these parameters. This paper presents a Bayesian Network (BN) model for the offshore drilling operation. The model uniquely considers the evolution of hazards as a function of time and space, and failure of the safety barriers. The model development is explained using the bowtie approach, which is routinely used in the industry for risk management. The bowtie model is subsequently transformed into a BN model and simulated for the well blowout scenarios. The blowout risk is updated based on operational field observations. An uncertainty analysis is also conducted to capture the spatial variability of the parameters. The results of the BN model provide a dynamic risk profile of the blowout accident during the drilling operation. Other possible accident scenarios, such as lost circulation, can also be analyzed using the proposed model. The proposed BN model serves as a robust tool for risk management of offshore drilling operations.