Global subsea equipment solutions specialist Ashtead Technology has successfully completed a subsea installation monitoring project for Ocean Installer AS in Equinor’s Askeladd and Johan Castberg fields.
The contract saw Ashtead Technology provide its integrated Deflection Monitoring System (DMS) services and equipment to support the installation of eight Integrated Template Structures (ITS) in the fields located in the Northern Norwegian Sea.
During operations, the dual independent DMS systems monitored, calculated, displayed and logged structure deflection, heading, pitch, roll, depth and suction can differential pressures, in real-time. This method of real-time monitoring is vital during the placement of suction can based subsea structures as it ensures any potential issues can be anticipated without delay, reducing the risk of structural damage.
The scope of work took place in quick succession over a 25-day period. This saw the project completed well ahead of schedule and resulting in significant cost efficiencies.
During the placement of the structures, the DMS systems were configured for autonomous independent operation, communicating data to one of the installation ROVs. Ashtead Technology utilised a range of measurement sensors and positioning tools along with special techniques to enhance the accuracy of the data collected, ensuring maximum performance of the system.
The Aberdeen headquartered business provided field engineers to support the operations offshore and were responsible for analysis of data and compiling of installation reports for each of the structures within 24 hours of completion of each structure installation.
Ross Macleod, technical director at Ashtead Technology, said: “When completing subsea installation projects, it is vital that the information provided is accurate, reliable and delivered in real-time. This reduces the risk of damage to the structure during installation and ensures it is installed within specification on the seabed, providing a complete audit trail to support this for the client.
“For this project, we utilised our unique DMS service including highly trained specialists and latest monitoring technologies to deliver all eight installations safely and well within client specifications in just 25 days – well ahead of the planned completion date. This performance highlights the accuracy and capabilities of our DMS services and the benefits our robust monitoring systems and services deliver to critical operations.”
Jeff Morris, Ocean Installer offshore manager – Normand Vision, said: “The DMS system proved invaluable for the safe and efficient installation of the ITS structures during the Askeladd and Johan Castberg projects. With onboard field engineer support, real-time information software and multiple display options we could continuously react to the changing seabed conditions during operations. The data provided ensured that all eight ITS were installed to client specification. The system proved to be both robust and accurate.“
Deflection Monitoring System (DMS)
Monitoring for offshore and IMR applications
Ashtead Technology’s DMS product range is a diverse family of structural monitoring solutions for offshore construction and IMR applications.
With our field proven standard in-house software and data management systems and precision survey instruments, our DMS system has been used for monitoring structural deflection of structures such as manifolds, templates, PLETs, rigid jumpers and TLP tendons.
Being modular and scalable we can configure robust and reliable systems easily and can provide powerful but easy to use and understand graphic visualisation software, allowing fast learning and minimum potential for error, across the vessel and if required in real time to your desk with our real time NetViewer™ applications.
With remote communications systems providing safety benefits and ability to provide full Internet based support of offshore operations from onshore, our systems have delivered a major step forward in creating a safer, lower cost operating environment, with proven backup support throughout your operations wherever you are. 24 hours a day, every day.
Our DMS systems can be easily configured for dual independent template and manifold structure installation, providing monitoring, computation and visualisation of:
Structure land-out:
Suction pile pull-in:
- Installed depth
- Depth differential to reference
- Attitude
- Linear deflection
- Torsional distortion
- Suction pile differential pressure
Features
- Fully integrated monitoring system using proven technologies
- Configurable platform, allowing easy adaptation for specific applications
- Robust and reliable systems with proven track record
- Fully recoverable system
- Compatible with all field positioning acoustic systems
- Easily re-deployed for multiple structure installations
- Intuitive graphic visualisation displays
- Full on-board data logging at subsea and surface
- Real time remote surveyor capability
- Remote management and diagnostic capabilities
Measurements:
- Heading, pitch and roll
- Structure depths
- Linear and torsional deflection
- Pile differential pressures
- Battery voltage, current monitor
- Spare channels for auxiliary sensors
Built-in features – subsea system
- Acoustic data link (cNode, cNode Mini S, 6G and Benthos compatible) RF data link
- ROV wet-mate connection for power and signal
- RF, acoustic and ROV remote data access, power control and remote diagnostic monitoring
- Inbuilt flight recorder data logging with csv format file and USB browser data retrieval for easy import to Excel, etc
- Battery condition monitoring using subsea display or telemetry