Keep drilling when others stop

Matrix LGS® (Longitudinal Groove System) has been designed to reduce VIV and drag to allow rigs to keep drilling when they would normally have to stop. Based on simulated eddy profiles for the Gulf of Mexico, this can translate into an annual increase of 20% more uptime during eddy current events which equates to hundreds of hours, potentially saving around $15 million in lost time per annum.

Matrix LGS® delivers a significant increase in rig capability at a small capital cost and will give those who adopt this new technology a clear advantage over competitors who don't. Matrix's engineers are ready to carry out detailed riser VIV analysis to estimate just how much your operation would benefit from using Matrix LGS®.

LGS is a registered trademark of AMOG Technologies Pty Ltd

Key features

  • Significantly reduces VIV and drag when compared with conventionally floated risers
  • 20%-30% increase in raw operable current speeds (in regions of the world investigated), including crabbing advantages
  • Estimated 20% more uptime during eddy current events
  • VIV fatigue damage rates five to ten times lower
  • Comparable buoyancy and manufacturing costs to conventional modules
  • Easily stacked both vertically and horizontally
  • Inherent anti-roll stability on moving decks
  • Can be used with existing riser handling and storage equipment


Introducing Matrix LGS riser buoyancy systems

Matrix LGS® - Proven and tested



Paper (2017): Drilling riser case studies comparing the drag performance of LGS technology to conventional buoyancy units and fairings

Johnstone, D., Potts, A.E,, Marcollo, H., and Kurts, P., (2017) Proceedings of the 36th International Conference to Ocean, Offshore and Artic Engineering ASME 2017 OMAE, June 25-30, 2017 Tondheim, Norway.


Deepwater drilling risers have a substantial portion (>70%) of buoyancy modules covering their entire length. The circular cross-section of these modules acts as a bluff body exhibiting significant Vortex-Induced Vibration (VIV) response, resulting in fatigue in the riser/wellhead and drag force amplification of the riser. 

Drilling operations can be suspended when the drag force on the riser adversely affects the top and bottom angles, a response which is exacerbated by drag force amplification due to VIV.

In 2015 and 2016, Longitudinally Grooved Suppression (LGS)1 technology was developed to field qualified Technology Readiness Level (TRL of 6) [1] offering a technical advantage to drilling operators over existing options.

In order to investigate the relative performance and quantify the benefits of LGS over conventional cylindrical Drilling Riser Buoyancy Modules (DRBMs) with and without fairings, a series of case studies encompassing typical operating conditions at drilling locations in several regions around the world (including the Gulf of Mexico, Brazil, the North Sea, and Australia) have been carried out to examine the performance in terms of drag (affecting operability due to top angle) and fatigue damage rate of the riser. The results indicate that LGS outperforms conventional buoyancy risers and fairings-equipped risers with regard to riser operability limits and fatigue.

Copyright © 2017 ASME 

Paper (2016): Drag reduction and VIV suppression behaviour of LGS technology integral to drilling riser buoyancy units

Marcollo, H., Potts, A.E., Johnstone, D., Pezet, P, and Kurts, P. (2016) Paper number OMAE2016-54689 published in proceedings of ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2016, Busan, Korea, June 19-24 2016.


Drilling risers are regularly deployed in deep water (over 1500 m) with large sections covered in buoyancy modules. The smooth cylindrical shape of these modules can result in significant vortex-induced vibration (VIV) response, causing an overall amplification of drag experienced by the riser.

Operations can be suspended due to the total drag adversely affecting top and bottom angles. Although suppression technologies exist to reduce VIV (such as helical strakes or fairings), and therefore reduce VIV-induced amplification of drag, only fairings are able to be installed onto buoyancy modules for practical reasons, and fairings themselves have significant penalties related to installation, removal, and reliability.

An innovative solution has been developed to address this gap; LGS (Longitudinally Grooved Suppression). Two model testing campaigns were undertaken; small scale (sub-critical Reynolds Number flow), and large scale (post-critical Reynolds Number flow) to test and confirm the performance benefits of LGS.

The testing campaigns found substantial benefits measured in hydrodynamic performance that will be realized when LGS modules are deployed by operators for deepwater drilling operations.

Copyright © 2016 OMAE