The offshore oil and gas industry still shows difficulties to develop a further improvement in hydrocarbon leak (HCL) prevention. As an initiating event of major accident 1 scenario, an HCL shows potential failures that under slightly circumstances could lead to severe consequences. Once an HCL occurs, there are learning opportunities that can lead to overall safety improvement, but recurrence or similarities between different events challenge the confidence about the completeness of improvement mechanisms and their ability to develop learning. Created after major accidents and broadly used in main offshore provinces, the functional regulatory regime (FRR) assign to companies the risk ownership, a clear mandate to develop all necessary actions on risk control. The main challenges for FRRs make the goals clear among risk owners, to lead conditions to a proper selection of risk constraints, and to support risk control by sustaining a high-risk awareness among all stakeholders. However, an accident shows failures in risk control, despite laws, regulations or other tools designed to avoid it. This article compares the Brazilian and Norwegian oil and gas offshore functional safety regulatory approaches considering the circumstances from selected HCL case studies. Accidental causation models are also considered in the discussion to support the assessment of the case studies' background, the socio-technical interactions, and the regulatory strategies, identifying improvement opportunities for HCL prevention and recurrence avoidance.

This study aims to analyze different indicator's programs from regulators and other organizations, select and apply methods to normalize and compose global indicator. Using obtained information related to risk management system and incidents from 67 oil and gas production platforms in Brazil, the results show a new method to follow offshore performance and its companies, in lagging and leading focuses, showing a tool to improve Regulator's overview.

Several incidents in the offshore oil and gas industry have human errors among core events in incident sequence. Nonetheless, human error probabilities are frequently neglected by offshore risk estimation. Human Reliability Analysis (HRA) allows human failures to be assessed both qualitatively and quantitatively. In the petroleum industry, HRA is usually applied using generic methods developed for other types of operation. Yet, those may not sufficiently represent the particularities of the oil and gas industry. Phoenix is a model-based HRA method, designed to address limitations of other HRA methods. Its qualitative framework consists of three layers of analysis composed by a Crew Response Tree, a human response model, and a causal model. This paper applies a version of Phoenix, the Phoenix for Petroleum Refining Operations (Phoenix-PRO), to perform a qualitative assessment of human errors in the CDSM explosion. The CDSM was a FPSO designed to produce natural gas and oil to Petrobras in Brazil. On 2015 an explosion occurred leading to nine fatalities. Analyses of this accident have indicated a strong contribution of human errors. In addition to the application of the method, this paper discusses its suitability for offshore operations HRA analyses.