Persistence of Low Windspeeds and Effects on Risk Estimates in QRAs

Quantitative Risk Assessment (QRA) and related studies have been used for more than fifty years to assess risks from major accident hazard facilities. Historically, QRA has primarily been used as tool for demonstrating risk to the public and workforce to meet regulatory compliance. Over the years, QRA and its application has evolved and now plays a significant role earlier in the project design to compare concepts, optimize design and cost effective risk management.

During the early design and engineering phases of offshore production platforms project, a number of critical design decisions are made including concept selection, capacity/throughput, technology and equipment selection, layout finalization, subsurface design, type of fixed or floating structure. All of these have significant impact on the inherent risk of a facility. The use of QRA in early design decision making enables the benefits of an inherently safer facility to be realized and can support effective risk management to achieve an optimal risk-based solution

Developing the QRA early in the project design phase poses challenges due to the limited details of engineering design data available. The challenges have been overcome by a screening-based version of the QRA, which utilizes data and information gathered from previous production design projects to supplement the design data so that the QRA can be applied early in the project to support project decisions.

Traditional methods for gathering and collating input data for the QRA are labor intensive and time consuming. Recent development, have enabled electronic data extraction directly from native engineering documentation, for example from piping and instrumentation diagrams (P&IDs) and 3D Models. These enhancements in information processing allow greater flexibility of the application of QRA and enables the study to respond to design changes throughout the project design phase and give feedback to the design teams more rapidly than before.

This paper identifies the lessons learned and best practices in designing safer production facilities that can be realized from the key advancements in the process and application of QRA. This paper will discuss the following advancements that have been developed and tested to improve the efficiency and quality of the risk studies:

• Enhancements in QRA tools through automated data extraction and processing of native engineering documentation.
• QRA screening techniques that utilize data from previous project designs to supplement sparse engineering data early in project lifecycles.
• The application of QRA results in early project phases to provide project teams with sufficient data to support decisions that are key to providing an optimal risk-based design that recognizes the inherent risk implications of concept selection and early layout decisions.