Combined and Re-Deployable Platform and Storage Solutions for Stranded Reserves

Abstract Unlock marginal and stranded reserves in shallow waters that are far away from existing infrastructure. The solution is a system that employs a jack-up based mobile offshore production unit (MOPU) in combination with a modular subsea storage system. The storage system is an unmanned solution that is designed with an integrated offloading system. Integrated into a single, integrated system, this robust solution encompasses all necessary components thus reducing both CAPEX and OPEX. The case is based on standard MOPU designs with compact process modules to reduce weight and cost. Additional cost savings come from standardization and placing fully integrated components subsea. An integrated process train ensures the right quality of oil or condensate is sent to the subsea storage tanks, ready for tanker pick-up. This paper also describes how the associated gas will be handled. The field-proven offloading system is linked to storage, ensuring correct metering and safe mooring for any vessel. Combining modular subsea solutions with field-proven components gives operators access to technologies that provide an increased return on invested capital. The storage system is developed based on existing storage solutions. It is an energy-efficient system with a low environmental footprint. Recent engineering studies and testing have proven the feasibility of operating a subsea storage unit with a flexible membrane defining the horizontal interface between oil and seawater. This paper presents new results from a downscaled subsea storage system model testing conducted by an original equipment manufacturer (OEM) together with a major operator. The innovative cluster design will enable re-deployment of the storage units, which opens new combination possibilities with MOPU's. Interfaces between the various system components have been streamlined to create an integrated system and when deploying these different building blocks in that way, a custom field solution can be provided for marginal field developments – including an option to modify and re-deploy. Research has shown that replacing the floating storage and offloading vessel (FSU/FSO) with subsea storage reduces offshore manning and the environmental footprint. This technical paper explains the modularity and the economics of an installation-friendly design. Lower complexity, in combination with cost-effective installation, introduces new opportunities for field developments. The integrated solution is also designed with the option to operate below wax appearance temperature and can make even smaller field developments profitable at a lower cost, in an energy-effective manner, and with a low environmental footprint. With this new solution available, the market can take a whole new view on small pool developments.