With the scene now apparently set for a long-awaited global decommissioning drive, RBG director Roger Esson discusses what it takes to retire offshore installations safely and efficiently.
Despite the high oil price and drive to extract more reserves from existing fields, decommissioning projects across the globe are on the rise as many installations near the end of their life-cycle. Oil & Gas UK advised in its Decommissioning Insight report, released October 2010, that it expects around £27 billion to be spent on decommissioning services in the UKCS over the next 40 years. In March this year, the US Bureau of Ocean Energy Management, Regulation & Enforcement (BOEMRE) said that the Iron Idle legislation could lead to a spike of 25% in decommissioning activity in the Gulf of Mexico over the next three years.
As the industry approaches the challenges of cessation of production and the decommissioning of assets it is essential that in the effort to reduce costs, projects are carried out safely, efficiently and competently. Contractors that provide integral support services, such as specialist cleaning, waste removal and management, NDT (non-destructive testing) and access solutions, have a direct role in delivering decommissioning to these high standards.
RBG has established an extensive 12-year track record providing integrated services on major decommissioning projects such as Maureen, MCP01 and North West Hutton. The lessons learned and experience gained demonstrate that involving contractors in the early planning process, having a key focus on safety and training, and developing and deploying innovative technology significantly improves the safety, efficiency and cost-effectiveness of the related workscopes.
Working together
Clarifying the workscopes, developing the methodology, working practices and quantifying the resources required to progress the project, will help ensure it is delivered in a safe and efficient manner. The detailed plans developed as a result of this process will allow the work to be scheduled to maximise resource utilisation, optimise activity and improve logistics. Integrated project plans with multi-skilled teams is one way to improve efficiency while reducing the numbers of personnel offshore, for example, mobilising multi-disciplined technicians that utilise rope access solutions.
One significant challenge in the minimisation of offshore manhours is ensuring the cleaning of process systems is carried out to a standard of cleanliness that is safe and acceptable, without being excessive. This will vary from system to system and RBG works with operators to develop a specific guidance on cleanliness (GOC) document to minimise offshore cleaning on installations, based on the client's requirements and the knowledge gained from previous projects. This GOC document has been used to challenge workscopes developed by operators and, in one case, demonstrated a 50% reduction in offshore cleaning manhours.
Safety standards
Decommissioning can be seen as just another phase in an asset's lifecycle; however, it is important those working on the installation recognise the profile of risks will change significantly. The move from hydrocarbon production to an active reduction in the hydrocarbon inventory changes the working practices and other specialist service providers, such as waste handling specialists and heavy lift contractors, become involved in the project. While safety is always of paramount importance on a producing platform, introducing new people, processes, equipment and changes to the installation's operating philosophy means everyone has an even greater role in ensuring that safety remains the primary focus and the highest standards are maintained during decommissioning.
An important difference from 'steady state' producing operations to the decommissioning process is that the physical operating environment is constantly changing. For example, the number of first aid injuries from debris in eyes can increase as people access areas of installation that may not have been entered for a number of years, such as redundant modules and the splice areas between modules. Air movement in these areas will increase the levels of dust and, if not properly considered, can present an issue. One such situation was remedied by the onboard asbestos crew building improved welding habitats, rather than using the conventional scaffold and tarpaulin approach. Following this implementation, no further eye injuries were sustained by the welders onboard. Also, due to ongoing workscopes in all areas of the installation, safety escape routes may not be available as they were during the operational phase and can change on a daily basis.
According to James Broadribb, RBG's operations manager, who was heavily involved in the successful delivery of the North West Hutton topside decommissioning: 'The introduction of large numbers new personnel who are unfamiliar with an installation can often be perceived as a potential risk by the existing platform team. However, people that are new to the installation can offer a different perspective and see potential hazards that may have not been spotted. Feedback like this is invaluable and should be actively encouraged.'
Broadribb adds: 'In-depth inductions are crucial for new personnel. They must be fully aware of the project scope, working practices and potential hazards. Their competency levels must also be evaluated to determine where additional training is required. This will ensure the most suitable teams are mobilised for each project and workscope.
'Safety sessions held by the project manager are also an important part of the induction process. Each and every member of the project team needs to fully understand the importance of achieving the highest safety standards so that everyone goes home safely at the end of their trip.'
RBG has expended more than 500,000 manhours without a single LTI on decommissioning projects. This has involved various disciplines completing often complex and potentially hazardous workscopes such as those encountered in the decommissioning of MCP01, where a significant part of the activity focused on the removal of asbestos and utilised 60 skilled operatives. This scope was singled out by operator Total E&P, and RBG was awarded its 2006 Safety Award for excellence in this area.
Applying innovations
Developing and deploying innovative technology also plays a major role in delivering decommissioning projects to the highest HSEQ standards. In response to current and future legislation tightening the requirement to control overboard discharges, RBG developed its advanced sandwash system to provide a cost effective and environmentally sound method of disposing produced solids. Units were introduced following a 12-month development period and incorporate a mix of field proven equipment and techniques, and a novel approach to the chemistry and fluid dynamics of three phase separation to allow the clean-up of solids prior to overboard discharge. Since the introduction to RBG's service offering, the sand discharge results achieved are often below 1% oil content, which is well within 6% limit governed by the UK's Prevention of Oil Pollution Act (POPA) 1971.
As asbestos removal forms a significant part of many decommissioning workscopes, ensuring personnel on board are not exposed to the potentially deadly material is crucial. Under the Control of Abestos Regulations 2006, exposure to asbestos dust is restricted to 0.01 fibres per cubic metre of air over four hours. To comply with this legislation, controlled wetting techniques are often deployed. A wet strip injection system, which comprises a series of needles hooked up to a water pumping system, is used to remove material from pipework. The needles are inserted into the lagging around the pipework at a constant rate to saturate the asbestos and significantly reduce the level of debris released into the atmosphere upon removal.
A number of innovations were developed and introduced for the decommissioning of BP's North West Hutton platform topsides removal project in the North Sea, which afforded time savings and increased safety, whilst adhering to environmental requirements.
A specifically designed semisubmersible pump was successfully used to remove oil from the overboard dump caisson before its removal. Due to the restricted access and potential hydrocarbons, a small air operated pump was designed for use within a custom built lifting frame, which had to be small enough to insert within the caisson access point and lowered 25m. This small pump, measuring no more than 8in in diameter, was used successfully with all oil removed and transferred to suitable waste receptacles for onshore disposal without release to the environment.
Another first was the safe handling and removal of densitometers, a radioactive sealed source of Caesium 137 attached to the legs of the jacket which had been used during its installation. Whilst the RBG specialist cleaning personnel were trained, competent and experienced at handling Naturally Occurring Radioactive Material (NORM), it was the first time that the handling and packaging of a sealed radioactive source, which originated from the initial platform construction, had been carried out. The team were trained in the handling and packaging of radioactive sources for safe onshore disposal under the guidance of the Radiological Protection Advisor onboard.
During the NDE (non destructive examination) phase, it became apparent that problems would exist in carrying out inspection of nodes on the flare that had previously been coated using thermal sprayed aluminium. It was simply not practical for the coating to be removed to carry out the examination. As a result, the NDE team developed a specific procedure that enabled the tests to be carried out without removing the coating, a first for the industry.
In addition, the welds on the drilling derrick structures were found to be galvanised. As a result, new procedures for ultrasonic testing had to be developed and new calibration blocks were ordered and galvanised so that NDT (non destructive testing) technicians could be trained and competency checks completed.
Conclusion
Decommissioning an offshore installation is a long and complex process which requires the operator and contractors to work together to safely deliver the project. Involving contractors in the early planning stages can significantly improve the efficiency of workscopes and optimise the working processes to reduce manhours and personnel onboard.
Safety remains of the utmost importance and the relevant training must fully explain the potential hazards of moving from a live to a hydrocarbon reduction environment and the changes in risk profile. As well as ensuring the correct personnel with the right skills are mobilised, deploying innovative technology and working practices, such as RBG's advanced sandwash system can bring real HSEQ benefits. Working to these standards and operating practices, contractors can help operators reduce costs while ensuring a focus on achieving the highest safety standards are maintained.
Roger Esson was appointed RBG's decommissioning director in April 2011. A BSc graduate from Robert Gordon University, Esson has more than 10 years' experience in senior management and operational roles in the energy industry. He project managed the successful delivery of the major North West Hutton topsides and MC P01 decommissioning project.
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