Description | This study uses event tree analysis to estimate the reduction in risk associated with alternative configurations of blowout preventer (BOP) systems used in deepwater drilling. The report summarizes information from the SINTEF database, which covers 573 blowout events, dating back to 1/1/1955 and as recent as 11/23/2009 and builds on an earlier study on the same subject done by DNV for the Canadian National Energy Board. This study determines the risk reduction associated with BOPs having two sets of blind shear rams and the risk reduction associated with each of several alternative emergency back-up control systems. The main contributions of this study are sensitivity analyses on the reliability assumptions for individual BOP subsystems used in the earlier analysis and an identification of which alternative back-up control systems offer the best improvement in overall system reliability. |