Buoy supported riser installed at Guara-Lula

Automation systems provider Cougar Automation has developed and commissioned a control system for Balltec to use on the first buoy supported riser (BSR) system installed on Brazil’s Guara-Lula project.

Buoy supported riser tether adjustment, using a linear chain tensioner.  Photos from Cougar Automation.

Guara-Lula is the largest engineering, procurement, installation and commissioning subsea umbilicals, risers and flowlines contract ever to be awarded in Brazil.

Operated by Petrobras and located in Santos Basin about 100mi off the coast of Rio de Janeiro, the BSR system consists of four submerged buoys each weighing approximately 2000-tonne, laying about 300m below sea level.

Cougar Automation was commissioned by Balltec to design a dedicated control and automation system, consisting of a surface-mounted primary control that would control the movement of the buoy support system via tether adjustment, using a linear chain tensioner. This was required in order to manage the tension in the risers.

The system allows surface control of the subsea tensioner system via an ROV. Once over-boarded, the ROV facilitates establishment of the data pathway linking the surface control to the subsea control modules. The surface control is then used to effect buoy movement as required

The system enables the controller to make adjustments to the position of the buoy using the tensioners, via visual monitoring and control using surface-mounted touch-screen human machine interfaces.

The surface control system is also able to automatically interrogate and identify the exact tensioner it is connected to, as well as generating advanced statistical reporting, operational and historical data for convenient trouble-shooting and audits.

The control system can also make rapid decisions in real-time to protect the equipment and facilitate safe operation; which a human would be incapable of. This includes highlighting of any anomalies to the operator and the generation of events during normal operation. This ensures that the system can be protected against any damage quickly and efficiently.