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Integrated Drillings System by NST
New Subsea Technology solves fatigue problems
NST has developed a new type of well foundation for Aker BP, and will deliver the finished commercial product to Aker BP in August. The development has taken 8 months, and is coordinated by NST and performed in cooperation with Neodrill and two other suppliers.
Saving time and money
The well foundation will be constructed onshore and installed by vessel utilising a crane and a ROV ahead of arriving location with the drilling rig. The drilling rig can therefore focus on drilling activities when arriving location. We expect that the system will reduce time and cost for the operator. At the same time, the operator will limit the exposure to people and the environment, through fewer and safer operations and reduced environmental footprint and emissions.
Launching the world strongest well foundation
- Strongest there is!
As far as we know this well foundation is the strengest on the market. Existing systems have experienced strength and fatigue limitations. We have taken the maximum loads developed by the industry and DNVGL the last few years, and designed the first product with significant safety margin. We also have the possibility to make it even stronger if required.
Designed for the highest stresses and fatigue scenarios
The well foundation is designed to withstand the highest loads defined in the Norsok standard and from DNVGL recommended practice (RP). At 125 m waterdepth and when using a 400 mT subsea BOP, the system still has more than 119 days fatigue life with a design factor of x10. The system is designed for a bending moment equal to holding a VW Beetle with a straight arm at 1300 m distance. The system can also hold more than 2000 mT of vertical weight.
Removing the critical welds
Through our experience with deepwater well design, we have experienced the limitations of the conventional wellhead systems with regards to stress and fatigue, specifically in relation to the upper circular welds of the system. The conventional systems have been subject to significant design iterations to achieve maximum fatigue life and strength. NST has removed the critical welds and replaced with machined products. Geometry and design alternatives have been analysed and optimized through FEA (Finite Element Analysis). NST believe this solves the problem the industry have been working for the last 10 years, and feel comfortable with our solution.
Transferring the loads to the formation
The suction pile technology has been used to transfer the loads to the formation, through the well known CAN system by Neodrill. The specially designed well system is integrated with the CAN for optimized load transfer and stability.
Using Compact Flange technology for well systems
NST has worked closely with the Compact Flange supplier and developed the technology for well applications. The Compact Flange technology is a unique static connection which can be used for dynamic applications. Compact Flanges are typically used for dynamic riser systems. The new application means that we can optimise the design to match the industry requirements for load transfer and internal well pressure separately, which makes the design easier.
Cooperation with subsea suppliers - adapted to standard wellhead construction systems and products
Developed in cooperation with Aker BP - Commercially available now!
Aker BP has ordered the first product, which will be delivered in August 2018. The system is planned to be used on an upcoming well by Aker BP. Estimated delivery time for new products will be around 5-6 months from order.