Floating offshore production installations: From challenge to opportunity?
The world’s Floating Production Storage and Offloading (FPSO) fleet is getting older. Fifty-five FPSO units in the global fleet are reaching the end of their design life in the next five years, and a further five have life extension in place. With 19 more FPSOs currently being evaluated for life extension, is the industry doing enough to transition from challenge to opportunity?
ABS is no stranger to the FPSO market, Fig. 1. It classed the first FPSO vessel in US waters in 1978 and continues to lead safety and innovation with new technology that supports larger, more complex FPSOs operating in ultra-deep water and in the pre-salt region of Brazil.
With more than 60% of all FPSOs in service being classed by ABS, and over 70% of FPSOs in Brazil operating under ABS Class, ABS—the Houston headquartered global provider of classification and technical advisory services to the marine and offshore industries—is committed to setting standards for safety and excellence in design and construction.
Focused on safe and practical applications of advanced technologies and digital solutions, ABS twelve months ago brought together leading companies in the FPSO sector. The vision was to form a consortium to help address the safety challenges produced by a fleet where more than half of the FPSO vessels are over 30 years old, and a quarter are over 40 years old.
It is a bold move that aims to advance industry best practices to protect people and the environment—bringing together industry leaders to address risks within the current and anticipated FPSO fleet. Two overriding goals of this consortium include:
- Identifying critical risks posed to the offshore industry by an aging global FPSO fleet.
- Determining the steps to mitigate safety and environmental risks posed by aging FPSOs.
Aging units require more maintenance effort to maintain in class, and maintenance needs to increase with age to reduce downtime. Across the industry, it is widely accepted that increases in life extensions put an increased burden on aging asset maintenance issues.
The consortium—which includes Chevron, Shell, Petrobras, MODEC, and SBM Offshore, as well as the Bahamas Maritime Authority, the Republic of the Marshall Islands Registry, and the U.S. Coast Guard 8th District—has created five joint industry projects (JIPs), aimed at using technology to tackle a range of FPSO safety issues. These include:
- JIP to establish/update acceptance criteria for composite repairs of steel structures
- JIP to establish acceptance criteria of the life extension of wire ropes
- JIP to develop an application to support management of gauging data
- JIP to support applications of 3D LiDAR Laser Scanning
- JIP on the application of Image Recognition Technology.
The JIPs, which make up much of the work activity of the consortium, are in advanced stages and are used to help share experience, knowledge, ideas and ways in which critical risks can be better managed from a safety, efficiency and cost perspective.
Members of the consortium are discussing how new learning can be factored in to future FPSO design (Fig. 2), including how class rules can be enhanced to further provide support for tomorrow’s FPSO designers, newbuilds and operators, in addition to emissions reduction. A number of rule changes have gone into effect during 2022 and will have an impact on the way industry mitigates challenges on aging structures and systems. Class rules have been improved, and several new measures have been implemented, aimed at improving the safety of the aging units and mitigating the challenges identified by the consortium. These include:
- Changes to the New Construction and Conversion Rules for FPSOs
- Changes to the Commissioning Rules for FPSOs
- Changes to the Rules for Inspection and Maintenance of Existing FPSOs
Three recent reports containing 10 best practices also have been published and accessed by industry stakeholders. These include Enhancing Safety on FPSOs: Practical Considerations for Operations and Maintenance; Enhancing Safety on FPSOs: Leveraging Digital Technologies; and Emissions Reduction Insights for Floating Production Installations.
LOOKING AHEAD TO 2023 AND BEYOND
The consortium is addressing issues on future units in tandem with a series of rule changes to address issues that have been verified on the existing aging fleet and to prevent the same safety issues from reoccurring on future units.
Challenges that have been addressed now require changes in the design phase, to mitigate some of the issues and costs for retrofitting and changes further down the line. Items such as corrosion aspects, structural design parameters and other more granular measures have been developed and included in the rules.
However, there are challenges beyond the well-known corrosion, structural integrity and systems integrity that need to be implemented, to address the growing concerns with environment and human aspects.
GREENER, CLEANER OFFSHORE OPERATIONS
Guiding industry across the energy transition and how best to address offshore emissions in meeting sustainability objectives is a continuing focus for ABS, Table 1.
The new ABS Guide for Sustainability Notations details the requirements for greener, cleaner offshore operations, and is the first sustainability guide to target the offshore industry that is developed with the involvement of major offshore industry clients from ABS to cover offshore asset compliance requirements.
It addresses topside functions on offshore assets, such as emissions and discharge, based on feedback from ABS clients, including ExxonMobil, SBM and MODEC. The guide outlines how carbon reduction technologies, such as zero-flaring and zero-methane slip policies, can enable assets to receive the SUSTAIN-2 notation—a key component of the energy transition—and it is an example of how class and operators can work together to develop a more sustainable industry.
As the search for oil continues in offshore deepwater environments, there is a need to build new installations for these locations. To align with the sustainability goals set by the U.N., the first step is examining the challenges faced in creating a low-emissions floating production facility unit.
If any net zero or global warming targets are to be met, we also need to factor in how to make current practices in key energy sectors, such as oil and gas, more sustainable. Vital infrastructure serving the offshore oil and gas industry, such as floating production installations, also warrants attention: floating, production, storage, and offloading (FPSOs); floating, storage, and offloading (FSOs); spars; tension leg platforms (TLPs); and semi-submersibles are just some examples. Floating production installations assist in the production, storage and transportation of hydrocarbons.
Why do they matter in net zero circles? Put simply, these offshore installations are important because of their operational characteristics and contribution to emissions and greenhouse gases, namely carbon dioxide (CO2), methane (CH4), fluorinated gases, nitrous oxide (NOX) and sulfur oxides (SOX).
As the leading class for offshore assets worldwide, ABS has a key role to play in supporting the industry through the energy transition, and the new ABS Guide for Sustainability Notations provides a pathway for industry to work together, to help reach its sustainability objectives by reducing offshore emissions.
INSIGHTS FOR FPSOs
In the Emissions Reduction Insights for Floating Production Installations white paper, ABS explored some of the major challenges faced in reducing emissions from a floating production facility unit.
As the search for oil in offshore environments continues, new installations will be needed. If we can address some of the emissions-related challenges, the sector can contribute to global decarbonisation efforts.
There are seven important issues, as follows.
Offshore application of technologies. Floating offshore production installations have various limitations and constraints. Often, these installations are located offshore in deep or ultra-deepwater depths. The topside production footprint is limited, due to space constrictions, which creates obstacles for accommodating additional equipment that otherwise would be able to operate on land. To reduce emissions from a facility requires the adoption of new or redesigned technologies that can be used for offshore applications.
Conventional methods generate emissions. Most installations use gas turbines to generate electricity to power vital equipment, such as compressors. This energy generation contributes to roughly 80% of all CO2 emissions from offshore activities—a situation which is exacerbated by the fact that these turbines are generally of low efficiency.
Even though the gas turbine method can provide a better alternative to flaring excess natural gas, emissions are still generated by the process. The use of emissions-capturing technology, or post-combustion emissions treatment processes, should therefore be considered to improve sustainability credentials.
Venting releases harmful gases into the atmosphere. Hydrocarbons and other harmful gases are released into the atmosphere during venting, a process which takes place during the loading and unloading of cargo tanks. The composition of these vapors depends on the crude oil in the tanks and various processes aboard the vessel; indeed, the amount of hydrocarbon that is mixed with the inert gas depends on many variables. It may vary from total inert gas with a combination of nitrogen, carbon dioxide, oxygen and traces of NOX and SOX, to complete hydrocarbon mixtures.
Pressurised systems and some loading phases may involve higher concentration levels of hydrocarbons, with vapors being cold-vented into the atmosphere, if there are no emission control systems installed. While there is heavily regulated guidance relating to venting, attention does need to be paid to operations and technologies that can reduce or even eliminate the need to vent such gas mixtures.
Excess gas can result in flaring. Flaring (the burning of excess gas) can occur for many reasons. The most common factors include a lack of local market capacity or demand, lack of storage and transportation systems, government tax incentives, operational challenges, original design limitations and changing reservoir performance.
Flaring emits greenhouse gases (GHGs) to the atmosphere. During the process, methane is oxidized to carbon dioxide and water through combustion. While this method is more favorable than venting, as CO2 is less impactful than methane as a GHG over a longer time span, methane may still escape unburned, depending on the efficiency of the equipment and gas composition.
Unplanned emissions can occur at almost any time. Another challenge associated with offshore production installations is the release of what is commonly referred to as fugitive emissions. These are unplanned events, whereby hydrocarbon gases and vapors are released into the atmosphere, and they can be associated with leaks, faulty equipment and other operational issues. Specifically, fugitive gases may be released during maintenance, piping joint leakage, valve leakage, relief valve discharge and flaring operations.
Water disposal and hazardous waste practices can be improved. Water is produced and utilised during, and for, various operations on offshore production installations and should be treated before disposal. Whether it’s produced water, hydrostatic testing water, cooling water, desalination brine or other wastewater like sewage or food waste, there is potential to cause serious harm if it is not managed appropriately.
Meanwhile, hazardous materials, such as chemicals, trash (gloves, rags and pads), oily water, paints, coatings and solvents should be either disposed of, or recycled, properly. Processes and equipment maintenance should also be optimised to reduce the risk of hazardous waste spillages and help protect marine life.
Noise disruption to marine life. Topside equipment and the associated supply vessel operations of floating production installations can generate considerable noise. This can lead to a domino effect of problems for marine life. By fleeing noisy areas, marine creatures face shrunken habitats, and vital activities, such as migration, food gathering and breeding, are disrupted. As a result, populations could decline and reduce ocean biodiversity.
FPSO SUSTAINABILITY DRIVES
A WORLD-FIRST FOR INDUSTRY
Recently, the ABS-classed Liza Unity FPSO was awarded ABS’s SUSTAIN-1 notation—the first FPSO in the world to receive it. The SUSTAIN-1 notation demonstrates the vessel’s alignment with key elements of the Environmental, Social and Governance (ESG) requirements outlined in the United Nations’ Sustainable Development Goals (SDGs). This includes the design and construction of the unit, which is assessed against the requirements of the ABS Guide for Sustainability Notations.
The Liza Unity FPSO is the second FPSO to be built for ExxonMobil’s Stabroek Block development in Guyana. It is also the first FPSO delivered under SBM Offshore’s Fast4Ward® program and has an installed production capacity to produce approximately 220,000 bopd.
SOLUTIONS FOR FPSOS
Whether it is noise pollution, gas flaring, or use of inefficient turbines to generate energy to power equipment, there is a range of challenges that operators of floating offshore production installations, generating 220,000 bpd, need to address.
There are solutions to help overcome these issues. Every oil company/operator is making serious commitments to reach the net zero emission targets. Further guidance on decarbonization and digitalization are covered in detail in ABS’s white paper, which contains practical steps and insight on technologies which, in combination, could help transform the sustainable credentials of the sector. By taking even some of these steps, operators can demonstrate that offshore oil and gas can contribute to safer, sustainable and affordable energy from the oceans.
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