Xtreme Release (XR)™ Connector
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  • MFG: STL

Detailed Information

High Angle EDP                                                                                                                                                                   STL Logo 300 223 x 80.jpg

Any floating vessel connected by a riser pipe to a wellhead on the seabed must be able to disconnect rapidly from the 

wellhead in the event of a position-keeping emergency. If it can't, there is a high risk of severe damage to the vessel, 

potentially causing injuries and fatalities, catastrophic failure of the riser pipe, severe damage to the wellhead, and possibly 

loss of well containment.

Before the development of the XR Connector™, all connectors used across the oil industry as emergency release connectors 

were limited by the maximum bending force which can be applied across them before they would not disconnect - i.e. if you 

go beyond that level of force the connector becomes stuck and will not separate. The bending force across the connector is 

determined by the amount of bend in the riser (generally as a result of the rig or ship at surface moving off well centre) and 

so the bending limit before the connector gets stuck is called the Maximum Riser Angle. The Maximum Riser Angle has 

nothing to do with the maximum strength of the connector, it is a limit caused by the internal geometry of the existing design 

of standard industry connectors.

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This means that a drilling rig or ship struggling to maintain position at surface due to a storm could be allowed to move a 

considerable distance away from well centre without risk of the riser failing, but if it was to go as far as that, it would not be 

able to disconnect in an emergency – or so it was before the development of the XR Connector™.

The XR Connector™ differs fundamentally from all other subsea connectors because it is based on a face-to-face technology 

rather than a conventional male-into-female engagement. This key differentiator enables the XR Connector™ to release safely, 

reliably and repeatedly with up to 100% of maximum bending rated bending load applied. Existing connectors - even those 

that claim to be capable of ‘high angle release' - cannot separate with high bending loads applied, so the maximum 

disconnect angle (and therefore the maximum applied bending load) has to be limited to prevent lock-up.

Because the XR Connector™ has no maximum disconnect angle there is no risk of it locking up when released under load. 

This means that vessels can move much further away from well centre before disconnecting from the subsea wellhead, and 

when they do release, the vessel crew can be confident that there is no risk of finding the riser stuck. This reduces the need 

for pre-emptive disconnects when a vessel is working in marginal conditions, it gives the rig crew time to be certain that there 

is a problem before triggering a disconnect without risk of getting stuck, it allows a vessel to work to the physical strength 

limitations of the riser, not just the geometry limitations, it ensures that a rig can safely and confidently move away from 

location if an iceberg approaches and it ensures that after a disconnect, there is a competent, undamaged interface to 

reconnect with.

Even beyond normal operations, the XR Connector™ continues to shine. Because it doesn’t get stuck, ever, a rig with a failed 

BOP control system which has become anchored to the seabed by its riser, can safely and easily be released by triggering the 

XR™ by ROV. Even if the worst happens, and the riser fails, still the XR Connector™ offers hope - an ROV can release the XR™, 

the remains of the riser may naturally fall away or may need to be pulled away by a vessel with a tugger line and then a new 

riser or a capping stack can be installed.

The XR Connector™ provides radically improved vessel safety, significantly reduced environmental risk and reduced costs 

through greatly increased vessel operability. It is rated to 10,000psi hydraulic bore pressure and 5,000psi hydraulic function 


Every subsea rigid riser system should be fitted with an XR Connector™