Evaluation Method Of Offshore Blowout Preventer Integrity Assessment Based On Risk Assessment

Offshore Blowout Preventer(BOP)is regarded as the core of secondary well control equipment to ensure subsea drilling.Once BOP failed,it may cause catastrophic consequence.Analying BOP integrity and researching integrity evaluation methods of BOP in service can provide technical support for Offshore BOP integrity management and ensure the safety of offshore gas well.The research launches the work emphatically on the following several spots:(1)BOP integrity concept is proposed by introducing concepts of structural integrity and physical integrity,which based on the study of structure and function of BOP.From the three aspects of human,machinery and environment,the integrity evaluation index system of offshore BOP is established.(2)BOP system hierarchies into components layer,equipment layer and system layer since BOP is a complex construction with multiple parts and system integrated.The hierarchy will outline how a BOP work and whether a failure has an adverse effect on the overall functionality.It provides a basis for calculating the system failure rate and characterizing the integrity degradation of the system.(3)Considering the factors of human,equipment,environment,the evaluation index system for the failure consequence of BOP is proposed.Considering offshore working condition,the quantitative criteria for the classification of the failure consequence of offshore BOP is established.The failure consequence is divided into 5 levels.It is using extension set theory and matter-element theory that gives the evaluation method of failure consequence.(4)On the basis of risk analysis,the integrity evaluation criteria of mechanical indexes such as such as damage and sealing are established by using magnetic memory method,which provides the basis for judging the integrity of the system.(5)The integrity management software of offshore BOP is developed,which is to consolidate information management such as BOP stacks parameters,testing and monitoring information,risk assessment,accident management.The goal of this software is to provide individuals and companies convenient tools for field application.Bsed on the research,a set of integrity evaluation process for offshore BOP is established,which provides a foundation for the practical application of the project.