High-pressure high-temperature (HPHT) oil fields in the Gulf of Mexico demand upstream subsea production system (SPS) equipment such as trees, connectors, and manifolds rated for 20-ksi or 400°F.This paper covers the project execution of production equipment for the world's first developed 20-ksisubsea field. This paper includes introduction of new technologies, digitalization efforts, and challenges encountered during the development, manufacturing, and factory testing of this equipment.
The development phase of the project began as a multi-year joint venture between OEM and energy companies. This phase included API qualifications and design of core components to industry guidelines such as API 17TR8. Digital analysis tools such as computer-aided design and 3D modeling and tolerancing(CAD and CATS), structural and fatigue analysis using finite element methods (FEA), simulated assembly and operation of equipment in a virtual involvement, and integrated multiplatform optimization software were leveraged for rapid final product development with minimal need for physical testing. To push design ratings to HPHT levels, it was necessary to implement new patented technologies into the design such as couplers, seals, tooling, and lockdowns.
The equipment-build phase included upgrading involved plants to state-of-the-art manufacturing and testing facilities. New processes were developed such as using custom fastener pre-load equipment, ultrasonic inspection methods, virtual-build simulations, and new high-pressure test cells with automated remote monitoring and testing capabilities. Subsea deployment of this equipment is planned for 2023.
Production systems rated to 20-ksi were built and tested for the first time. New technologies and processes were successfully integrated and validated in an overall assembly. Higher capacity systems introduced new failure modes. The general strategy for HPHT component design is to leverage existing, lower capacity designs but to make the geometry bulkier and the material stronger. A second strategy for design is to reduce the overall loads by reducing pressurized areas, pressure balancing, and offsetting weights. Both approaches lead to new challenges such as weight management, material failures, material sourcing difficulties, seal failures, size restrictions, industry requirement interpretations, cost requirements, assembly complexity, and safety considerations. Development of equipment for 20-ksi fields can be completed in a safe and sustainable manner.