The offshore oil and gas industry, even in times of low prices and abundant supply, is driven by the almost relentless search for new fields to replace those coming toward the end of their natural productive lives. Often this forces exploration in ever more challenging environments and places huge demands on the boundaries of technology.

And these challenges are no better exemplified than in the design and construction of subsea flowline infrastructure in very deep waters, where operators strive for ways to shorten project lead times to reduce both development costs and the time to ‘first oil,’ which is critical in terms of project cash flows. This has demanded innovation in both technology and working methodology—necessitating close working partnerships with clients and the supply chain alike.

Deepwater flowline infrastructure takes many different forms and configurations but a universal demand is for methods to retain position relative to vessels, wellheads and other subsea structures. Such methods must allow for tidal range, subsea currents, inherent buoyancy and variable weight. Critical in securing a solution is the method of holding or clamping equipment in place.

The demands this places on existing technology and design solutions is illustrated in the development of a tool-assisted piggyback blocking clamp system, designed to allow the development of the Laggan Tormore project off the Shetland Islands by Subsea 7.

During the installation and operation of pipelines, a secondary line is sometimes introduced attached to the main pipeline using a piggyback system to provide adequate support. The Laggan Tormore project required the simultaneous installation and long-term subsea deployment of 140 km (87 miles) of a primary 8-in. diameter pipe with a secondary 2-in. pipe attached or ‘piggybacked’ on top of it. This involved RED Engineering developing a new, semi-automated clamp and installation system in less than 12 months. As a result installation rates increased from 200 m/hr to 1,200 m/hr (656 ft/hr to 3,937 ft/hr) while generating savings of several million dollars due to tumbling installation times.

Another area to benefit from the latest in fast-track design and engineering innovation is around the economic, safe and efficient servicing and maintenance of subsea oil wells in deep water.

When FMC Technologies was developing its new vessel-based well intervention system, a requirement was identified for a subsea umbilical clamp as part of the equipment spread to securely ‘hold back’ a compressible control umbilical cable deployed to operate subsea hardware. This threw up a particularly challenging requirement as the umbilical cable was compressible and because it comprised of a series of cables and hoses (electrical, fiber-optic and hydraulic) couldn’t be squeezed excessively when clamping to avoid internal damage.

A clamp solution, featuring an innovative arrangement of spring-applied pads to give a consistent squeeze pressure over a 3 m (10 ft) length without resorting to a more complex electrohydraulic system, was designed and commissioned in less than seven months. Key to the success here was prior knowledge of the friction properties of subsea cables and the ability to quickly test and validate a potential solution.

There’s no doubt that as oil and gas reserves become more difficult and costly to recover, the demands for innovative technology will continue to grow, providing opportunities for engineering companies who have grown up on the back of innovation and engineering excellence, to show their capabilities. Investment in new technologies and engineering talent alongside experience gained working around the world will continue to secure a strong position for oil and gas service expertise in the times ahead.

— Joe Orrell, RED Engineering

Offshore