The Ocean Ranger Oil Rig Disaster: A Risk Analysis

This paper analyzes quantitatively the design of the Ocean Ranger off-shore oil drilling rig that capsized and sank on February 15, 1982 off the coast of Canada. A review of the actual disaster is also included based on evidence gathered by the Canadian Royal Commission. The risk analysis includes the construction of a failure modes and effects analysis (FMEA) table, a fault tree, and a quantitative evaluation including common cause failure of the rig components. In the case of the Ocean Ranger ballast control system, it was shown that the analysis was able both to successfully model the catastrophic system failure of the portholes, the actual system failure mode, and identify a common cause failure mode of the pump system. This study represents an application of reliability and risk techniques to the oil services industry.