Full Scale Fibre Rope Deployment System – Joint Industry Project
BMT Marine Projects Limited supported by BMT Fluid Mechanics Limited and OTM Consulting Limited have successfully convened and embarked on Phase 1 of the latest Fibre Rope Deployment System, a Joint Industry Project consisting of major Oil Companies, Deep Sea Installation Contractors and Specialist Suppliers.
The offshore oil and gas industry is starting to explore in water depths at the limits of current development technology and has plans to access acreage in up to 3,500m. It is developing subsea production systems in preparation for ultra deep production which are larger than prior equipment deployed in deep water. In addition, the drive towards more complex subsea equipment (subsea metering, subsea processing) will increase the overall number of components installed on the seabed. The time scale for ultra deep production systems installation is approximately 2012, but the planning will need to take place around 2009 with the confidence that a system for installing equipment has been developed and proven.
As field developments have progressed into ever deeper waters, traditional methods for lowering subsea hardware on steel wire ropes have become increasingly inefficient, because a greater proportion of the winch capacity is required to support the weight of the wire rope. Large and heavy payloads have alternatively been installed in deep water from the drillstrings of large drilling semi-submersibles, but the day-rates for these rigs are high, and their availability is limited. The availability and financial implications of using large drilling semi-submersibles make this an unattractive option. Flotation devices have also been used to help decouple the motions of the payload and installation vessel, but these systems have limitations in flexibility and speed of deployment.
Therefore, a key technology for the future economic development of deepwater fields will be a system which can be installed on a conventional construction vessel, which is capable of deploying large objects to great depths, and is also efficient for installing the many smaller lifts associated with modern subsea systems.
The industry has recognised the need to develop systems for the reliable deployment of equipment to the seabed in very deep water (beyond 2,000m) and has funded several JIP activities (e.g. through DISH and DEMO 2000) in order to develop the technology. The focus had been on the use of fibre ropes to replace steel wire rope, and the JIPs have advanced understanding of fibre rope behaviour and developed the technology for fibre rope deployment systems (FRDS) at 1/5 load scale.
Individual winch manufacturers have developed conceptual winch designs. Installation contractors have considered both how existing wire systems can be stretched to their limits, and the functional and practical requirements for fibre rope systems. The capability and limitations of buoyancy-supported systems have also been evaluated.
To date, however, it has not been possible to demonstrate the practicality of FRDS systems at full scale. The requirement is now to build on prior work and to develop, test and demonstrate a full scale FRDS. This cannot be done convincingly on a laboratory test rig or at small scale. In planning the way forward it is appropriate to consider how prior activity, which has been largely complementary but not co-ordinated, can be made more efficient by bringing the development activity into a single focussed JIP.
The FRDS JIP is now underway with Phase 1 culminating in the production of a full functional specification for the system, industry wide invitation to tender and response assessment to complete the ‘due diligence’ process. This will finally lead to an independent recommendation from BMT for the most economic and risk mitigated option to take forward into Phase 2 - full scale manufacture, testing and demonstration.
BMT Marine Projects Limited is specifically being used to facilitate and coordinate the FRDS JIP process because of its independence from manufacture and experience with high value, technically demanding and high risk projects.