Drill riser buoyancy

Balmoral's low drag VIV (LDV) suppression buoyancy is designed to reduce offshore operational costs through innovative technology. The Balmoral DURAFLOAT LDV™ integrates vortex induced vibration (VIV) suppression and drag reduction into drill riser buoyancy modules, enhancing rig efficiency without compromising safety. This system minimises vessel downtime, leading to significant cost savings.

Testing and validation

• Extensive CFD and fluent modeling indicate up to 75% VIV suppression and 33% drag reduction
• Half-scale tank testing at SINTEF Ocean confirmed strong performance

Key benefits

• Up to 75% VIV Suppression – Improves riser motion and reduces drag in challenging subsea currents
• Hex design – Eliminates the need for additional suppression equipment, saving time during drill stack operations
• Enhanced fatigue performance – Reduces riser motion, improving the service life of wellhead and conductor/casing equipment
• Improved operational windows for drilling in heavier seas
• Reduced drag and loads during deployment/recovery
• Significant reduction in VIV fatigue damage
• Negligible loss of buoyancy
• Easy stacking and handling
• Compatible with existing riser handling and storage equipment
• This technology ensures optimal uplift values and significant operational efficiencies, making it a valuable asset for offshore drilling operations

Balmoral DURAFLOAT LDV™

• Drilling riser buoyancy foam
• Modules are produced using proven manufacturing techniques
• Minimal buoyancy loss
• Operational to 4500msw

Balmoral DURAGUARD LDV™

• Retrofit option for existing drill riser buoyancy modules
• Significant cost savings via re-use of existing buoyancy
• Alternative to VIV strakes
• Improved handling and stacking
• Improved roller deployment

Integral clamp LDV buoyancy

• Alternative to VIV straked production riser buoyancy
• Utilises patented integral installation methods

When transporting and storing drill riser joints, pin and box end connectors are always subject to potential damage.

To prevent unnecessary and expensive repair work to these critical areas, Balmoral provides a range of lightweight, high impact and abrasion resistant elastomer protectors.

With growing numbers of drilling contractors recognising the latest in high performing PU pin and box end protection, Balmoral can help achieve easier handling, fitting, transportation and storage by providing these highly cost effective products.

Polymer riser clamps are now recognised as an industry standard solution whilst offering significant weight reduction in deep and ultra-deepwater environments.

A conventional drill riser comprises of a 21”diameter main line with choke, kill, booster and hydraulic lines surrounding it. These service lines require to be connected to the main body by means of clamps to prevent buckling when the riser is operational.

Historically, steel clamps have been used – quite often “burn outs” from thick steel sheet – which are heavy and cumbersome when attaching to the riser. However, as drilling depths become greater the requirement for weight saving on riser strings has increased.

One area where this has been possible is through the evolution of polymer riser clamps. Initially the steel clamp evolved to a combination of a steel strap with polymer elements and thereafter to a full polymer product.

Maintaining its policy of product innovation and continuous improvement, Balmoral optimised its riser clamp design in terms of functionality, handling and ease of attachment to the riser string.

The design optimisation process resulted in a clamp that is:

• Extremely robust
• Highly impact resistant
• Offers a significant weight saving when compared to steel
• Vastly reduced assembly time
• Custom designed to suit specific riser requirements

The Balmoral riser impact protection system allows the bare joint to be stored in the same stack as buoyant riser joints and minimises the chance of operational damage during deployment and recovery.

When running a bare riser string, ie, without buoyancy modules, several problems can be encountered on the drill platform including:

• Storage difficulties because of the differences and irregularities in profile
• Impact damage while being passed through the rotary table

To minimise damage during operations Balmoral provides a selection of riser impact protection systems:

• Rotationally moulded polyethylene modules for standard protection
• A combination of polyethylene and polyurethane elastomer modules for heavy duty protection and maximum stacking

These products are engineered to provide maximum impact and abrasion protection whilst at the same time being lightweight and easy to handle.

Balmoral riser protection modules are fitted around the riser with moulded apertures accommodating auxiliary lines and riser clamps.

In addition to riser impact protection modules Balmoral manufactures polyurethane elastomer stacking shims which provide intermediate protection along the riser length and are suitable for protecting standard slick joints, pup and telescopic joints.