An Integrated System-Oriented Methodology for the Risk Analysis of Offshore Oil and Gas Drilling Industry: AcciMap and Bow-Tie United
Authors: Tabibzadeh Maryam , Mokhtari Mohammad 
Published: April 2018

Abstract
The analysis of previous (offshore) oil and gas drilling accidents indicates that Human and Organizational Factors (HOFs), in addition to technology- and work processes-related elements, play a critical role in contributing to those accidents. These HOFs are originated from different layers of key involved decisions-makers, both internal and external to an organization. This paper proposes a system-oriented methodology for the risk analysis of oil and gas drilling industry by integrating the two powerful frameworks of AcciMap and Bow-tie.
In the first phase, the AcciMap framework, which was originally proposed by Professor Jens Rasmussen in 1997, is used as a systematic accident investigation methodology for the analysis of the BP Deepwater Horizon (DWH) blowout, as a case study. This graphical representation, by incorporating associated socio-technical factors into an integrated framework, provides a big-picture to illustrate the context in which an accident occurred as well as the interactions between different levels of the studied system that resulted in that event. In the next phase, the results from analyzing the BP DWH accident using the AcciMap framework are used as a foundation for the development of a Bow-tie model. This model, as a barrier-based risk assessment framework, introduces both preventive and mitigation barriers that by incorporating them into an analyzed system, respectively, the likelihood of occurrence of future accidents and their negative consequences will be reduced.
The analysis of the BP DWH accident indicates that aside from influencing external components, organizational factors such as economic pressure as well as communication and interoperability issues, both in regular and emergency situations, were the root contributing causes of this accident. This analysis is then used for the identification and development of appropriate barriers in our proposed Bow-tie framework. In addition to organizational factors, human factors and technological elements have contributed to this accident and other cases. Those are also identified and used to develop approporiate barriers in our Bow-tie framework.
The integration of the two frameworks of AcciMap and Bow-tie, which are compatible with each other and complement each other, provides a novel comprehensive perspective to better analyze operations in high-risk systems such as the oil and gas drilling industry. It is noteworthy that although the utilized AcciMap framework was developed for the analysis of the BP DWH blowout, our defined preventive and mitigation barriers in our Bow-tie framework are generalized to represent other (offshore) oil and gas drilling cases as well. Therefore, our proposed integrated methodology can be used for the risk assessment of operations in the entire (offshore) oil and gas drilling industry. Furthermore, this paper and its proposed methodology provides a roadmap that can be adopted by any safety-critical industry; e.g. petrochemical processing, transportation and nuclear power, for the risk analysis of its operations.