DESIGN AND PERFORMANCE OF SAFETY INSTRUMENTED SYSTEMS TO AVOID ENVIRONMENTAL RELEASES: A CASE STUDY OF THE BOP

Abstract

Blowout preventers (BOPs) are safety-related instrumented systems used during drilling or well intervention operations mainly to stop kicks. It is desired to stop a kick because of its potential to damage the environment and also to prevent the accident that can lead to loss of people and asset. The main focus in this project, however, has been on role of BOPs in avoiding environmental releases.

Following the Deepwater Horizon accident in the Gulf of Mexico, the world’s attention has fallen on the blowout preventers. This is mainly because of the vital role of BOP in accident prevention and mitigation. There are not a lot of studies on subsea BOP reliability, however the most applicable studies are performed by Rausand (1983), Holland (1999), and WEST (2009).

This study focuses on BOP reliability in a qualitative approach. Standards and regulations in relation to BOP are reviewed and classified. Also, Failure modes and causes of individual component failures are identified and classified according to IEC standards using a failure modes, and effects analysis (FMEA). Finally, a fault tree analysis (FTA) is carried out to define the reliability of a BOP when a kick is present. In this report, it is tried to not only focus on the BOP itself, but consider it as a part of larger safety system. Recommendation for future standards based on literature review and results of this study are made. The current report is provided basis for a quantitative study of subsea BOP reliability.