Cable installation offshore Brazil

The Mero (formerly Libra) development in the Santos Basin required the installation of a PRM Permanent Reservoir Monitoring (PRM) system, consisting of a complex subsea assembly: a dynamic umbilical riser connected to a Data Unit Transfer Assembly (DUTA) with five pigtails extending from the hub. The products needed to be deployed as a single system to maintain connectivity, but the geometry of the bundle introduced handling challenges, particularly in controlling the pigtails without creating uneven loading or overstressing the lines. Maersk Supply Service required a lay methodology that would ensure predictable handling throughout the deployment.

MDL carried out a FEED study to determine how best to manage the bundle through initiation, transfer and overboarding. The study compared multiple tensioner configurations and evaluated deck layouts, squeeze requirements and routing paths. A hybrid solution was developed, incorporating bespoke W-pads to allow one of the tensioners to grip the umbilical and pigtails as a single, stable package, alongside MDL's unique Wheeled Horizontal Lay System (WHLS) to guide the assembly through the vessel moonpool.

MDL enabled Maersk I-Class vessel, the Skandi Involver, with a complete back-deck spread, featuring four tensioners, a Generation 2 Reel Drive System, hydraulic winches and the WHLS. The back-deck arrangement of the tensioners and custom deflectors enabled the complex multi-line installation without undue stress on the product; while MDL's large-capacity tensioner combined with the WHLS frictionless wheel mechanism facilitated low-friction deployment, reducing drag and ensuring optimal product integrity during installation. The campaign demonstrated the value of defining the installation methodology early and reinforcing MDL’s track record in supporting complex cable and riser lay scopes in deepwater fields.