Wellhead Load Relief (WLR) System / BOP Tethering
ICON Engineering is a pioneer of wellhead load relief systems (also called BOP Tethering) in Australian waters. In partnership with leading global equipment suppliers and analysis houses, we offer an effective and proven turnkey solution for upstream operators.
The management of wellhead strength and fatigue during drilling plug and abandonment (P&A) and well intervention operations is an emerging issue for operators. The evolution of increasingly larger, heavier Blow Out Preventers (BOPs) has exacerbated the challenges faced when latching onto legacy wellheads.
Wellhead Load Relief (WLR) systems, also known as BOP Tethering systems, have been developed to provide support to the BOP during P&A and workover operations, where fatigue or strength issues are predicted by analysis. A WLR system restricts the motion of the BOP stack above the wellhead, substantially minimising static and cyclic stresses on the wellhead and extending the fatigue life.
Depending on the specific configuration of the BOP, riser and wellhead, analysis has shown a WLR system can deliver an improvement of 25 to 1000 times the untether wellhead fatigue life.
Use of an WLR system can also improve rig operability by increasing the limits of the rig’s watch circle above the wellhead. In shallow water, rig watch circles can be very restrictive and the station keeping limits of dynamic positioning (DP) systems can easily be exceeded, particularly in adverse weather conditions.
A tethered BOP increases the rig operational window and supports the performance of the rig’s DP station keeping. Wellhead offset loads due to drive off/drift off can be reduced by factors of 3 to 4, meaning safer operations and less waiting on weather-related non-productive time (NPT).
ICON have a proven track record supporting operators minimise the risks of wellhead strength exceedance and fatigue accumulation. We have partnered with the industry’s leading equipment suppliers and geotechnical experts to supply and operate WLR systems. ICON’s in-house engineering, project management and operational expertise supports the development of bespoke WLR solutions to suit project and environmental requirements.
ICON is not just a supplier of the equipment but offers a complete turn-key solution to WLR services. We pride ourselves on taking ownership of WLR operations and coordinating interface management across the full suite of third-party contractors, optimising rig & vessel operations to reduce operators’ costs
Our WLR system scope of supply includes:
- Project Management
- Equipment Maintenance, Recertification and Testing
- Operations Support, including Rig and Vessel-based Support
- Project-Specific Planning, Engineering and Design;
> Geotechnical Assessment and Engineering with Market-leading Local Partner
> Equipment Specification with Wellhead and Conductor Analysis Contractor
> Optimised Field Layouts
> BOP Attachment Points
> Subsea Tether and Rigging Design
> Transportation and Installation (T&I) Engineering
> Installation and Operations Procedures and Manuals
- Procurement and Logistics (where required)
- Onshore / Quayside SIT and Support
ICON is proud to use ROV-operated Linear Rope Tensioners (LRT) developed by SubseaDesign of Norway. Over 150 of these LRTs are in service, and over 260 wellheads have been supported by this equipment.
Image Credit: Subsea Design
ICON partners with Norwegian Geotechnical Institute for geotechnical analysis supporting the selection and design of anchoring solutions according to field conditions.
ICON have designed, built and installed both gravity base and suction can foundations for the WLR system. We have successfully executed multiple WLR system deployments in Australian waters, utilising both suction can and gravity base anchoring systems.
Our equipment and experienced operational team is available to support WLR deployments globally.
