Products & services / Buoyancy & SURF
Matrix LGS® SURF
Reducing costs and fatigue
The need to compromise between drag loading and VIV suppression has always been a design challenge for SURF engineers. Matrix Composites & Engineering is proud to offer a solution to overcome this conundrum: Matrix LGS®.
Matrix LGS's® innovative profile was inspired by the Saguaro cactus whose modest root system manages to keep the slender plant upright even when buffeted by the strongest of winds. It's the cactus' grooved profile that ameliorates the effect of high winds by interfering with the vortex formation process.
Designed for use across a range of applications, the system’s passive and low profile reduces the amplitude of any VIV response while maintaining drag loads at, or below, the level of the bare cylinder.
Matrix LGS® is easily installed before or after deployment, increasing operational flexibility whilst significantly reducing life cycle costs.
- VIV suppression: Typical VIV suppression efficiency up to 80% at full coverage
- Low drag: Typical static drag coefficient of 0.6 (at LGS® OD)
- Reduced drag amplification compared to bare cylinder (Vandiver equation ideal cylinder)
- Fully qualifed system:
- Hydrodynamic performance independently qualified in small- and large-scale lab tests
- Full scale field trials (LGS® on drilling riser buoyancy) confirm findings from lab tests
- Materials fully tested and qualified to meet API 17L requirements for abrasion protection equipment
- Manufacturing processes in line with pertinent DNV and API requirements.
- Fully developed response models:
- Riser Systems: Force model integrated into Shear7
- Pipeline and Jumpers: Response model corresponding to DNVGL-RP-F105 methodology, including adjustment factors for partial coverage
LGS® Retrofit products offer all the features of our standard LGS® Strakes but can be fit onto the host structure after these have been installed. This may be useful in scenarios where VIV fatigue was not expected. For instance, when seabed scour leads to excessive pipe spans, or other sources of fatigue occur during operation, such as unexpected slugging in spools.
Furthermore, the ROV Retrofit option is particularly useful when there is a need to retroactively reduce riser displacement in an effort to free up space for new additional risers in a tie-back development.
LGS® Integrated Buoyancy
The option to integrate the LGS profile into buoyancy modules reduces costs and requirements for secondary equipment attachments. As Steel Lazy Wave Risers (SLWR) become more widely used, heave induced VIV is becoming a real issue; LGS® integrated buoyancy modules offer a simple and cost-effective solution. LGS® integrated buoyancy also opens up new design solutions for spool/jumper design.
BENEFITS BY APPLICATION
Matrix LGS® is appropriate for use across a range of application including:
- Dynamic risers (Flexible riser, Steel Catenary Riser, SLR, umbilical risers)
- Fixed risers and jumpers/spools
- Pipeline spans.
Benefits are far reaching and have been summarised in the following table according to application and associated Matrix LGS® feature (low drag, VIV suppression, and low and benign profile). Please note "dynamic risers" refers to flexible risers, steel catenary risers, SLR and umbilical risers.
Matrix LGS® benefits are common across all product categories.
Note: LGS is a registered trademark of AMOG Technologies Pty Ltd.
Matrix LGS - tested and proven
Paper (2019): Field trial of vortex-induced vibration suppression technology for drilling riser buoyancy.
OMAE2019-96426. 9 - 14 June 2019, Glasgow, Scotland.
Editorial (2019): VIV Suppression
Paper (2018): Mitigation of pipeline free span fatigue due to vortex induced vibration using longitudinally grooved suppression.
OMAE2018-77716. 17 – 22 June 2018, Madrid, Spain.
Paper (2017): LGS technology for Drilling Risers: Reducing Costs by Increasing Operability while Improving Safety.
Australasian Oil & Gas Exhibition & Conference (AOG). 22 – 24 February 2017, Perth, Australia.
Paper (2017): Drilling riser case studies comparing the drag performance of LGS technology to conventional buoyancy units and fairing.
OMAE 2017-62219. 25 - 30 June 2017, Trondheim, Norway.
Paper (2016): Drag reduction and VIV suppression behaviour of LGS technology integral to drilling riser buoyancy units.
OMAE 2016-54689. 19 - 24 June 2016, Busan, South Korea.