Operational risk in the oil industry may lead to environmental disasters and to heavy loss of human lives. This program discusses models to analyse and to assess the operational risk at the drilling, primary transport and refining stage of the oil supply chain. For the drilling stage, three sub-methods, one for each period of the plant life cycle (design, construction and production) are considered. For the primary transport stage, two different risk management processes are presented: one for allowing the risks resulting from processes, procedures and physical components (other than oil-pipelines) to be identified, assessed and controlled, and the other for allowing risks arising from the pipeline breakdowns to be faced. Finally, for the refining stage, a preliminary phase is recommended to prioritise each equipment of the refinery, and several techniques and tools are suggested. For Risk Managers and Analysts in the Oil and Gas supply chain covering upstream, midstream and downstream operations.