Shell Global Solutions Retrofits VIV Strakes on Medusa Spar

Shell Global Solutions (US) Inc. has successfully completed the industry's first replacement of vortex-induced vibration (VIV) helical strakes with patented ROV retro-fit fairings along a 595-ft. stretch of catenary pipeline riser on Murphy Oil Corporation's Medusa SPAR, located at 2250 ft. water depth in the Gulf of Mexico. By combining the patented RIVET NB(TM) VIV suppression fairing installation tooling and helical strake removal tooling developed by Shell Global Solutions, the replacement took just 24 days, including mobilization and demobilization. This deepwater catenary riser retrofit is an efficient method for replacing high drag helical strakes with lower drag fairing-style VIV suppression devices.

The RIVET NB installation system was developed and tested by Shell Global Solutions. It easily adapts to different diameter fairings to accommodate a wide range of pipeline sizes. The compact system requires relatively little deck space, which allows the use of small offshore construction vessels or minimal deck space onboard an existing structure. The RIVET NB system is mated to the ROV remotely, while subsea, and can then be taken as far as the ROV excursion tether allows to install its fairing / thrust collar set. The RIVET NB system takes two fairing / load collar sets per trip, minimizing vessel time on location. Also developed for the project was a set of strake removal tools that can accommodate any size strake to be removed. The helical strake removal tool set and the RIVET NB tool systems are designed for low impact operation on an existing deepwater vessel or platform.

Patented suppression fairings from Shell Global Solutions offer superior VIV suppression and very low drag loading when compared with conventional helical strakes. The high suppression and low drag properties of these fairings can significantly reduce deepwater pipeline costs by reducing the over-design needed to accommodate high drag and vibratory loads. When installed for stabilization of horizontal spans, they can also eliminate circuitous pipeline routes around sub sea canyons and steep slopes, saving time and money.

With over 2800 professionals, Shell Global Solutions helps its customers to maintain their competitive edge, optimize plant and process performance, formulate and develop new products and manage operational safety and environmental challenges more effectively. Shell Global Solutions provides solutions to a range of customers in the oil, gas, additive, chemical, motor sport and industrial sectors.

RIVET NB (Remotely Installed VIV Equipment Tool - Neutrally Buoyant) is a registered trademark of Shell Global Solutions (US) Inc. Notes to editors Vortex-induced vibration (VIV) is recognized as a hazard for deepwater offshore oil and natural gas producers. Vortices, or spinning eddies, are created (or shed) when a current of water collides with structures such as risers, tendons or pipelines. These vortices can cause severe oscillations of tubular structures in deepwater exploration and production environments. Oscillations caused by VIV can result in the bending of offshore tubular structures. This bending can create extremely expensive and environmentally hazardous fatigue failures. Fairings and strakes are devices that are attached to the tubular to suppress the vibration caused by vortex shedding. Notes to editors In addition to pipeline riser and span retrofit remediation, the VIV team from Shell Global Solutions also offers VIV analysis, VIV testing, suppression hardware supply and suppression installation services. Notes to editors Shell Global Solutions is made up of seven independent technology companies within the Royal Dutch/Shell Group of companies. Together, they can draw upon more than 50 years experience in research, development, technical services and operational expertise.