Balmoral DuraFloat & DuraGuard LDV

A new low drag vibration suppression system

Drill riser buoyancy

Drill risers extend from the BOP to the drilling vessel with their primary function being the provision of fluid communications between the well and the vessel while supporting choke, kill and auxiliary lines.

Buoyancy modules fitted around the riser provide uplift while reducing the submerged weight of the joints. This helps to minimise top tension and prevent stress in the riser as well as reducing loadings during deployment and retrieval of the blow-out preventer stack. However, drilling risers are prone to potentially catastrophic motions caused by subsurface vortex induced vibration (VIV).

Balmoral developed Balmoral DuraFloat LDV* and Balmoral DuraGuard LDV*, integrated and retrofit VIV suppression solutions respectively, to prevent such motion and drag occurring in the ever-deeper waters encountered in oil exploration and production.

These systems offer industry leading uplift while eliminating riser motion and high drag levels without compromising performance, safety or structural integrity and is available in two versions.

*Patents pending

Balmoral DuraFloat and DuraGuard LDV viv suppression

Hydrodynamics inspired by nature

Balmoral’s ground-breaking LDV profile was inspired by the carapace structure of a sea turtle’s upper shell which has been sculpted and proven over millennia to provide a highly efficient and low drag hydrodynamic structure.

The company’s technical team simulated this natural structure by implementing biomimetic engineering resulting in a manufactured system that brings VIV and low drag performance to its products.

The revolutionary hex design integrates VIV suppression and drag reduction technology into drill riser buoyancy modules eliminating the need for ancillary suppression equipment. This results in significantly improved timings when running and removing drill stacks.

In addition, it is well known that reduced riser motion, mitigated by VIV suppression, dramatically improves the fatigue performance of subsea equipment. This has further cost saving benefits by extending the service life of wellhead and conductor/casing equipment.

During the development process wide-ranging computational fluid dynamics and fluent modelling was carried out by Balmoral while comprehensive tank trials were undertaken by SINTEF Ocean to provide the information required for final product design.
Drill riser buoyancy hydrodynamics inspired by the hexagonal pattern on a turtle shell
DuraFloat and DuraGuard LDV - Direction of flow

Direction of flow
Blue directional arrows indicate deflection in the direction of flow. Red directional arrows indicate deflection transverse to flow, eg, VIV.

DuraFloat and DuraGuard LDV - Swirling strength

Swirling strength
Flow separation points create stabilising eddies either side of the buoyancy module preventing the system from vibrating.

Balmoral DuraFloat LDV

DuraFloat LDV is an integral part of the riser buoyancy module as it is moulded into the product during the manufacturing stage.

The system retains the familiar configuration of drill riser buoyancy to ensure service continuity from transportation to deployment. The introduction of the LDV profile provides the additional effectiveness of riser control across broader environmental influences.

Balmoral DuraGuard LDV

Designed as a retrofit option, Balmoral DuraFloat is added onto existing infrastructure.

Balmoral is aware of the significant investment made in riser buoyancy modules and, in recognition of this, developed DuraGuard LDV as a secondary cover allowing operators to improve and fully exploit existing collateral.

Applications

Marine drilling risers
Production risers
Umbilicals
Flowlines
VIV strakes
Jumpers
Long pipeline spans
Power cables

Benefits

Improved operation envelope
Significantly reduces drag and loads during riser deployment, recovery, disconnection and hang-off
Substantial reduction in VIV fatigue damage
Negligible loss of buoyancy over conventional modules
Eliminates assembly/recovery times
Stacks vertically and horizontally
Fully compatible with existing riser handling and storage equipment

Product enquiry

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