Inherently Safer Choices in Early Design of Offshore Oil and Gas Installations: A Multi-Target KPI Approach

As offshore oil & gas activities are currently evolving towards more productive yet complex situations, the availability of efficient safety metrics has become essential in the early stages of offshore oil & gas projects to underline potential major accidents hazards and clearly communicate safety criticalities. Inherent safety has demonstrated to be a widespread concept in offshore risk management strategies, but there are few preliminary studies in the existing literature about systemic indexing to orient the conceptual and basic design stages of the project lifecycle. In the present work, a methodology for the selection of inherently safer solutions was developed as a support tool for decision-making in early design activities of offshore oil & gas installations. The expected inherent safety performance of alternative design options is assessed by means of a comprehensive set of key performance indicators (KPIs) based on the simulation of consequences of offshore accident scenarios and credit factors of the possible loss of containment events from offshore equipment. The proposed KPIs aim to capture the hazard level of single units and to address selectively multiple targets of the potential threats than personnel and process equipment on the installation, such as marine organisms on the sea environment. Moreover, overall aggregated KPIs were introduced as a sound synthetic measure of the inherent safety performance of the offshore system. The method was applied to the assessment of alternative designs of an offshore production facility, particularly characterized by environmental and safety concerns. The results from the case study evidenced the capability of the proposed method in ranking the potential and credible critical units of each alternative configuration and identifying the relative magnitude of targets contributions to the global safety profile of the installation.