A real-time risk-informed BOP retrieval decision support tool to enable operators to determine when to retrieve the BOP for repair after a detected component failure.
DNV GL has launched the BOP-RDT, a real-time risk-informed BOP retrieval decision support tool to enable operators to determine when to retrieve the BOP for repair after detecting a component failure.
The tool transforms complex information, obtained by numerical computational algorithms, into a graphic visualization user interface. Users are presented with color-coded indicators of the reliability degradation of each BOP safety function due to any detected component or subsystem failure in the BOP.
THE DECISION SUPPORT TOOL FOR BLOW OUT PREVENTERS – REDUCE YOUR DRILLING DOWNTIME CAUSED BY BOP FAILURES
DNV GL’s new BOP Retrieval Decision Tool (BOP▪RDT) aims at improving drilling uptime
Unreliability of Blow Out Preventers (BOP) is among the major causes of downtime in drilling operations. The decision of BOP retrieval after detection of a failure can be one of the most costly decisions made in the drilling of a well.
In deep water the cost can be in the region of one or two million US dollars and in ultra-deep water conditions such as Brazil, West Africa and Gulf of Mexico this can easily double.
Undoubtedly, any detected failure in a BOP stack during drilling is an important cause of concern, but not all component failures are of equal importance. While the impact of some failures may lead to the total loss of a critical safety function, other failures may barely change its probability of failure on demand (PFD). Retrieval of the BOP for repair is a must in the first scenario. In the second scenario retrieval could be unnecessary. Between these two extreme cases there are a wide variety of intermediate cases where the retrieval decision must be made.
Many operators involved with offshore drilling have developed some kind of decision making process. While some are better structured than others, most of them are based purely on qualitative arguments.
Introducing the Real-Time Risk-Informed BOP Retrieval Decision Tool – Improving downtime and saving cost while managing risk
Developed by DNV GL’s industry experts in the Research and Innovation department, this tool provides the most comprehensive decision support system which escalates the decision-making process by substantially reducing its degree of subjectivity. Understanding the industry’s needs, it aims to help you reduce BOP downtime safely and effectively with noticeable cost savings on your drilling operations.
BOP RETRIEVAL DECISION TOOL
How does it work?
The BOP▪RDT incorporates both qualitative and quantitative methods to help guide your decision-making.
Using deterministic criteria, the BOP▪RDT has a comprehensive qualitative method which is entirely based on the losses of redundancy resulting from the impact of detected failures on the reliability of all BOP critical safety functions included in the Tool. The BOP condition states are reported to the user as a set of traffic light signals and block diagrams.
For organizations that are using probabilistic criteria, the BOP▪RDT offers a fully quantitative risk-informed decision support system. This is based on an advanced time-dependent reliability analysis of each safety function before (normal condition) and after one or more detected component or subsystem failures.
The quantitative method allows the evaluation of the PFD of each safety function in real-time. It provides a detailed graphic visualization of the impact of any component or subsystem failure on the values of the PFD of all BOP safety functions. The quantitative risk-informed criterion is based on the comparison of the PFD values of the safety functions with a range of Safety Integrity Levels (SIL) values as defined by IEC 61508.
Alternatively a combination of qualitative and quantitative methods and criteria can be used to support the BOP retrieval decision. Both in the qualitative or quantitative methods the BOP safety conditions (or status) are codified in four colours: green, yellow, orange and red.
Their general meanings are the same on both methods:
■ Green indicates a normal condition
■ Yellow represents a slightly degraded safety function
■ Orange indicates a seriously degraded safety but not disabled safety function
■ Red represents a very seriously degraded or disabled safety function
The detailed definitions vary between the two methods as they are based on different criteria: deterministic losses of redundancy in the qualitative method and comparison of PFD values with the ranges of SIL values in the quantitative method.
Advantages and benefits for the customer:
■ Reduces BOP downtime while maintaining acceptable safety margins
■ User friendly and intuitive operator interface (Excel based)
■ Provides deterministic qualitative and probabilistic quantitative results. Qualitative and quantitative methods allow its use in different regions of the world
■ No need for risk or reliability experience
■ Reduces subjectivity and improves consistency of BOP retrieval decisions
■ Speeds up the decision-making process by facilitating consensus
■ Increases transparency to various stakeholders and regulatory bodies
■ Includes three different failure rate models: exponential, Weibull and step-increase
■ Uses accurate numerical computational algorithms(multi-level testing)
■ Provides track record of failed and restored components
■ Fully customized to your BOP
Helping you work safer and smarter
About DNV GL
Driven by its purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification and technical assurance along with software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our 15,000 professionals are dedicated to helping our customers make the world safer, smarter and greener.
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