Case study
Beatrice Offshore Wind Farm Project – Pre-piled jacket installations
Scotland offshore Caithness coast
Client
Seaway Heavy Lifting
Project duration
March 2017 – Construction ongoing
Fugro provided custom built, real time decision support survey software capable of interfacing all survey sensors on a subsea pile installation frame. The software is allowing Seaway Heavy Lifting to install pre-piles within exacting tolerances, permitting highly efficient jacket installations while saving project time and reducing installation costs.
Life cycle
Planning, feasibility, conceptual design
Design
Construction
Operations and maintenance
Decommissioning
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Starfix® on demand positioning
Starfix® on Demand
Starfix® on Demand is an advanced offshore survey and positioning software that delivers efficient, adaptive and assured vessel positioning data. Supplied on a subscription basis, it increases operational flexibility through real-time remote services to reduce cost and HSSE exposure.
Fugro is providing survey support to Seaway Heavy Lifting for the installation of pre-piled jacket foundations on the Beatrice offshore wind farm project. The Beatrice offshore wind farm will be Scotland’s largest offshore wind farm and one of world’s deepest, with water depths up to 58 metres, and will comprise of 84 turbines each with a capacity of 7 megawatts. The turbines and two offshore transformer modules will be installed on top of 4-legged pre-piled jackets measuring between 68 and 81 metres each.
In this pre-piled jacket installation concept, it is of key importance to install the pre-piles accurately. To achieve this, a pile installation frame (PIF) was used with Fugro providing real-time decision support survey software using data from approximately 50 sensors. The majority of these were on the PIF with others located on the hammer, the seabed and the installation vessel. The software module was built to project specifications and rooted on Fugro’s Starfix® 2016 Suite software package. Accurate dimensional control surveys were carried out to position all the survey sensors in the PIF or vessel reference frame.
The installation of pre-piles within a crucial, tight relative height tolerance allows Seaway Heavy Lifting to install the jackets within attitude tolerance quickly and efficiently.
The jacket legs are stabbed into the pre-installed piles, meaning the relative pile height determines the jacket attitude directly. As a result, not only the relative stickup, but also the inclination, position and heading of the set of piles was of crucial importance for the work to be successfully delivered.
This first (piling) phase of offshore installations has successfully been completed. All the 344 pre-piles (86 x 4) have been installed within relative depth tolerances, achieving a 100% success rate.
Currently Fugro is providing survey support during the second phase of foundation constructions; the installation of the jackets on the pre-installed piles. The accuracy of the PIF surveys have been proven repeatedly by successful installation of over a third of the 86 jackets up to date and counting. It satisfying to see all the jackets ending up with attitude and heading well within design tolerances.
Successful installations
subsea pile
“Congratulations for this important milestone at Beatrice project (344 piles at 86 locations) and thank you for your contribution in turning the pile installation campaign into a great success! I would like to thank both the on- and offshore teams for the dedication and professionalism you have all displayed while developing the PIF solution software and ultimately offshore execution. Happy to see that you have overcome the challenging tolerances.”
Seaway Heavy Lifting
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