MDRB provides lift while reducing the submerged weight of the riser joints. This helps to minimise top tension and prevent stress in the riser while reducing loadings during deployment/retrieval of the blow-out preventer (BOP) stack.
Drilling risers extend from the BOP to the drilling vessel with their primary function being the provision of fluid communications between the well and the drilling vessel while supporting the choke, kill and auxiliary lines. The riser is also used to guide tools into the well and serves as a running/retrieving string for the BOP.
Dressed marine drilling riser joint
Balmoral marine drilling riser buoyancy modules are fitted around the riser with moulded apertures accommodating auxiliary lines and riser clamps.
The vertical lift of the syntactic modules is transferred to the riser by a thrust collar fitted to the riser pipe below the upper coupling. A matching collar is normally installed at the lower end of the assembly to facilitate the transfer of the module weight during handling.
MDRB technical information
External coating MDRB operates in extreme conditions and must withstand harsh and constant handling. Durafloat modules incorporate glass reinforced fibres to deliver a robust, impact-resistant performance.
Colour coding The international drilling community uses a colour system for quick identification of differing depth rated modules which is shown here:
Typical colour coding standards
Attachment methods Kevlar strapping with stainless steel axis bars and stud bolts is the standard system used to attach MDRB modules to the riser. Other options are available including through bolts or stainless steel U-bolts with enclosed Kevlar strapping.
Module stability 300mm flats are standard across the Durafloat range. This allows safe and effective stacking in the yard or in an offshore environment.
Flexural pads These are built into MDRB modules at strategic locations to ensure that excessive bending loads are not transferred from the riser to the module when lifted in the horizontal plane.
Ancillary hardware and services • Thurst collars
• Vortex induced vibration (VIV) strakes
• Riser impact protection device
• Pin and box end protectors
• Maintenance and installation of MDRB modules
Repair service We offer a comprehensive repair service to damaged buoyancy modules, including: • Repair of full breaks
• Rebuild of missing sections
• External reinforcement
• Void filling
