Operators on opposite sides of the world are mobilising European walk-to-work systems in support of offshore maintenance campaigns
MMA Offshore adopted a walk-to-work (W2W) crew transfer solution for a maintenance operations project on an energy company’s assets in Australia’s North West Shelf region.
MMA Pinnacle, an 87.8 m multi-purpose supply vessel (MPSV) was fitted with a pedestal-mounted gangway from Safeway for the two-scope project, which is the first application of such a system for platform shutdown maintenance in the region.
“So far, the system has performed exceptionally well,” says MMA Offshore deputy chief executive David Ross.
“We successfully completed 40 W2W transfers with over 1,200 personnel transfers,” he adds, noting: “The first scope of the project was completed within schedule and without incident. “
“The solution led to a significant improvement in productivity and reduced overall shutdown time for our client, due to the ability to implement two maintenance shifts. This was a key factor in differentiating this solution from the alternatives.”
MMA Offshore's use of a gangway has improved productivity and reduced overall shutdown time
While the gangway and mast were manufactured by Netherlands-based Safeway, a custom-designed pedestal, built in Singapore, was required to achieve the desired height access and allow for the integration and securing of the gangways system to vessel structures and systems.
Explaining how the W2W system was selected and the project developed, Mr Ross says: “A motion-compensated gangway solution was core to achieving the safest and most efficient means of transferring the personnel.”
The primary conceptual considerations were largely focused on platform transfer heights for the facilities, which are approximately 30 m above sea level, as well as the significant wave heights that the vessel was required to work in, notes Mr Ross, adding: “These two criteria were onerous in combination.”
At the next level, MMA sought a suitable vessel with sufficient accommodation capacity and high standards of comfort, serviceability and vessel motion behaviour: “We soon realised that all options required an elevated platform to raise the gangway off the vessel deck to meet the required platform heights,” says Mr Ross.
“When designing the pedestal and gangway system, we made every effort to ensure that mobilisation and demobilisation between projects could be achieved in a timely and cost-effective manner”
MMA Offshore undertook a series of studies which combined an analysis of the vessel and gangway performance, prevailing weather conditions and the expected optimum DP orientation of the vessel to the platform, to determine equipment and its position on deck. With a gangway type identified, more detailed operational considerations were analysed, including prevailing weather conditions (eg currents, wind and wave magnitude and direction), gangway functionality, number of passengers and frequency of transfer, safe access, traffic flow, DP and gangway operability.
“Throughout the entire process, personnel safety remained the ultimate criteria, while ensuring strict compliance to statutory and Australian Standards,” says Mr Ross. Several joint hazard identification (HAZID) sessions with the client, equipment suppliers and vessel operations staff were conducted with outputs feeding into the design.
Working in close partnership with the energy company client and equipment supplier from concept through to execution was essential to the success of the project, says Mr Ross.
Stable and safe transfers
This co-operation extended from site visits to Europe, to inspect equipment for suitability, through to design plan approval, HAZID sessions, client risk management, National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) Safety Case Approval, scheduling, logistics, project management and operational procedures.
“The gangway is motion compensated and allows for very stable and safe transfer of personnel in differing weather conditions at a height of 30 m above sea level,” says Mr Ross.
“The vessel’s DP hold capabilities, combined with the length-to-beam ratio of the hull and the gangway’s motion compensated systems, achieve a very good result.”
Daily health-checks, data recording and identification of potential faults are enabled by digital technologies integrated into the gangway system, which Safeway engineers can remotely access via VSAT communications systems and MMA data links on the vessel.
“By recording data such as wind strength, wave height and vessel roll through the equipment sensors, MMA is able to analyse the capability for future projects and the reliability of workability and simulation software,” says Mr Ross.
Currently, MMA Offshore has two work scopes committed for the project, the first of which ran from late April to mid May and the second of which is due to start in September. However, it is keen to market the system for further campaigns in the region.
“When designing the pedestal and gangway system, we made every effort to ensure that mobilisation and demobilisation between projects could be achieved in a relatively timely and cost-effective manner,” says Mr Ross.
“This allows us to remove the gangway and pedestal between contracts to ensure the vessel remains a flexible asset for a broad range of tasks.”
Elsewhere, MMA Offshore is providing W2W solutions to clients in three other projects, in Southeast Asia, India and Africa. Multipurpose work vessel MMA Privilege is currently operating as an accommodation and W2W vessel supporting FPSO maintenance in Côte d'Ivoire; it recently marked the 100,000 safe personnel transfer completed using an Ampelmann gangway that was installed on the vessel in January 2018.
“The solution led to a significant improvement in productivity and reduced overall shutdown time for our client, due to the ability to implement two maintenance shifts”
Offshore Brunei, MMA Pride is working as a W2W vessel using another Ampelmann gangway, performing boat-to-boat transfers, cargo lifting to and from facilities, and construction and maintenance support. And another multipurpose work vessel, MWV Falcon, has been fitted with an A-type Ampelmann Gangway to enable topside maintenance work in Mumbai for the 2018-19 Indian season for the last six months to June.
Louisiana-based Harvey Gulf Offshore Marine has also opted for a European W2W gangway system, having mobilised an Ampelmann A-type motion-compensated W2W gangway system as part of a project to perform maintenance work at an oil and gas platform in the Gulf of Mexico.
Harvey Gulf’s president Robert Gwinn explained the thinking behind the gangway mobilisation, detailing how it will facilitate the company’s aims for the project, and the company’s plans for crew access systems.
The A-type gangway has been mounted on Harvey Blue-Sea, a multipurpose support vessel (MPSV) that is providing flotel services for the maintenance campaign, which has an estimated duration of four to five months, according to Mr Gwinn.
The unnamed client had specified a W2W system be used for personnel transfer for the project, and Ampelmann’s solution met the specifications, he adds, noting that Ampelmann and Harvey Gulf worked together to tailor the system to meet the project’s requirements.
The A-type is mounted on a specially designed 10 m pedestal, enabling it to reach landing locations of 20 m and higher. The gangway will be operated by Ampelmann on a 24/7 basis, providing the client with greater time flexibility and an extended weather window.
Under the current contract, Harvey Blue Sea is operating purely as a flotel, so the gangway installation does not interfere with its ability to carry out other operations and is a temporary addition to its capabilities. However, Harvey Gulf is considering installing a motion-compensated gangway system on the upper superstructure – which would require reinforcement – of either Harvey Blue-Sea or sister vessel Harvey Sub-Sea. This would enable the vessel to carry out W2W transfers as well as undertaking other work, such as the deployment of up to two work-class ROVs or lifting operations, using its 250-tonne active heave-compensated knuckle-boom crane.