FMECA / FMEDA subsea drilling BOP (electrical and hydraulic systems)

MAR Consulting facilitated and documented a Failure Modes, Effect, Criticality and Diagnostics Analysis (FMECA / FMEDA) of the electrical and hydraulic control and safety systems of a major drilling contractor’s subsea drilling BOP. This work is part of an extended partnership to deliver such a product to the entire fleet of drilling rigs and ships. Description of projects MAR Consulting has been involved as part of this partnership: FMEA of electrical and control systems in subsea BOP · MAR Consulting; FMECA of redundant subsea BOP deadman-autoshear · MAR Consulting; FMECA electrical and control systems in subsea BOP · MAR Consulting; FMECA of blow-out preventer hydraulic system · MAR Consulting.

Purpose of the FMECA / FMEDA of the subsea drilling BOP

MAR Consulting facilitated the failure mode, effects, and criticality analysis (FMECA) based on the methodology described on international standard IEC60812. Since it also included analysis of diagnostic capabilities, it could also go by the FMEDA designation (failure mode, effects, and diagnostic analysis). However, the purpose was significantly different than most FMEAs. Typically, an FMEA evaluates a design with the objective to unveil its weaknesses (and strengths). As a result, this information can form the basis of a cost-benefit analysis for design improvement opportunities. In this project, however, in addition to the above, the drilling contractor/ operator will use the output to report hard failures to relevant authorities. In other words, the purpose was to build a database of reports to be queried when a failure does occur. Reporting of failures in deployed BOPs is an operational requirement in many parts of the globe.


The assessments covered the electrical and hydraulic control systems of the BOP, including subsea and surface equipment. The scope of the assessment included the electrical equipment involved in the activation of any particular function or emergency functionality. In conjunction with the hydro-mechanical assessment, an end-to-end FMECA / FMEDA assessment has been performed for all control and safety functions of the BOP system in the analysis.

Furthermore, MAR Consulting developed reliability block diagrams (RBDs) and qualitative fault trees (FT) to complement the assessment. They are meant to provide the drilling operator and their clients (operators) a better understanding of the reliability of the system, specifically when given failures occur.

The client integrates the assessment output into their trademarked and patented BOP simulation software. Main use cases of the software are visual failure analysis and testing of solutions; and an educational platform.


MAR Consulting facilitated the assessment partly in Houston and partly online. It builds on the shared knowledge and experience of the participants (drilling contractor and client personnel). MAR Consulting contributed with a solid background in electrical and hydraulic control systems, in addition to facilitation and scribing skills, to successfully deliver on this assignment.

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