In-house safety engineering expertise for FPSOs
As a deep-sea pioneer, Total has been implementing increasingly high-performing floating production, storage and offloading (FPSO) units for almost twenty years. They are designed and built according to internal technical standards in order to optimize and adapt their design to the operational requirements of each offshore field. Building on this experience, the Group has developed expertise and specific technical tools in the field of safety engineering for these FPSOs. Effectively preventing all risks associated with operating the units, these tools cover every stage in the life of a project.
Deep offshore: technical responses to new challenges
A special technical framework for FPSOs
The experience Total acquired by designing several FPSOs that are now in operation resulted in the drafting of internal design guidelines in 2009. This general specification details the safety philosophy and the methods intended to prevent the occurrences and limit the consequences of major accidents.
It ensures consistency between the international safety rules that apply in the offshore environment and those applicable to sea transport. This safety engineering framework is continuously enhanced by our operational experience and aims to guarantee a high standard of safety.
The safety engineering framework deals with fire and explosion risks through a special approach known as FPSO sectorization. This concept of segregated and independent “fire zones” significantly reduces the likelihood of the domino effect between zones in the event of a fire or explosion.
The Safety Concept, applying the framework to each FPSO installation
Applied to each FPSO unit, this framework can be adapted to the operational context in question. It establishes a general design framework that ensures standardization from project to project. Based on this general framework, we develop a single document for each project, the Safety Concept. It describes all the design guidelines having to do with safety that will be applied to the industrial context for a given FPSO. It ensures consistency between the prevention and protection methods for major risks: preventive measures at the design level, equipment installation principles, sectorization, detection principles and the automation that goes with them, core fire prevention design, etc.
Analyzing differences between standards
This “structured” framework can also be used to effectively analyze and compare internal standards with external ones. This approach makes it easier to analyze differences in safety engineering design. It defines the best possible options for a project that uses a different reference base. Applied to the Kaombo project, for example, it enabled the contractor’s proposal to be analyzed in detail and the safety engineering aspects to be defined for the solution, which involved converting two crude oil tankers into FPSOs.
Moreover, the Technological Risk Assessment (TRA), which is performed as a matter of course during the basic engineering and detailed engineering phases, ensures that the overall industrial risk is reduced to the “As Low As Reasonably Practicable” level (ALARP).
Effective risk studies for preventing major risks
Starting in the design phase of each FPSO, we conduct in-depth studies on the risks associated with gas cloud combustion and explosion to minimize the occurrences and consequences of these incidents.
The risk studies implemented for each FPSO involve analyzing many possible accident scenarios and modeling their potential consequences:
- 3D modeling of how the different modules are distributed on the FPSO helps to better simulate the consequences of an explosion, and accurately quantify and pinpoint the overpressure peaks they cause.
- Fixed fire and gas detection systems are positioned according to a smart mapping of locations where fire or gas leaks might start, so that they are detected as quickly as possible. Combined with a pressure relief system, an emergency stop and rapid system isolation, this detection minimizes the duration and the consequences of hazardous events.
- Protecting personnel is of the utmost importance, which is why evacuation routes are provided based on fire and explosion scenarios to ensure that they will be accessible and secure in the event of an accident. The location, the architecture and the size of living areas also satisfy safety criteria determined by analyzing a myriad of simulations: overpressure resistance, non-exposure of personnel to fire risks, etc. This approach helps to define “secure” zones from which controlled evacuation of the installation will be possible.
A comprehensive method for each project: Technological Risk Assessment (TRA)
For each project, before it is put into production, we deploy a scenario-based methodology known as TRA, i.e. Technological Risk Assessment.
Begun during basic engineering and updated right through to detailed engineering, TRA is used to estimate a project’s overall level of risk, to control it with safety barriers and to ensure that the risk is at the “As Low As Reasonably Practicable” level (ALARP).
This Group-specific methodology utilizes a detailed description of the installations, their procedures and their environment. It analyzes accident scenarios that generate major risks for staff, facilities or the environment, based on the selected options in the Safety Concept. The identified scenarios are evaluated, based on the likelihood that they will occur and the severity of their consequences.
This makes us feel confident that the technical prevention, control, mitigation and evacuation elements put in place do in fact minimize risk to the level expected in the risk prioritization matrix developed by Total. These safety aspects will be tested and inspected during the operational phase to ensure their effectiveness.