Developing Probabilistic Risk Assessment, PRA, for a BOP System Reliability

Recent regulatory changes have moved in the direction of more oversight and more prescriptive solutions. One of the areas that can help operators and drillers alike deal with the new regulations is improved risk analysis. This paper addresses a methodology for Probabilistic Risk Analysis (PRA) modeling of blowout preventer (BOP) systems. The PRA utilizes a combination of event trees and fault trees to determine the probability of a hazard under a given set of conditions. The fault trees are populated with reliability data from the best available sources. Traditional BOP risk analysis was done on a deterministic approach. The probabilistic approach will allow a logical method to assess top level hazards resulting from specific component failures. This approach has been used in other industries such as nuclear power and space exploration. A method of combining testing intervals with PRA results to determine the probability of failure on demand is also included.