We have extensive experience of IRM Services, with divers or integrating ROV tools and applications for managing and developing special projects. We have a proven track record of delivering a wide variety of subsea IRM activities.
Skills in IRM Services:
• Surveys/general inspections
• Non-destructive testing (ACFM, Ultra Sound, Eddy Currents)
• Anode inspection
• Anode replacement
• CP Measuring
• Marine growth removal
• Project management and engineering
• Rigging and lifting
• Drilling, cutting, welding
• Lost object location/recovery
• Cable-free span rectification
• Scour inspection
• UWILD inspections
• Multi-beam profiling, Cable surveying & inspection, Geophysical surveying
NDT – ACFM
ACFM (Alternating Current Field Measurement) is an electromagnetic technique for NDT detection and sizing of cracks. The technique derived from eddy-current. In an ACFM probe, there is an array of eddy-current units. The ACFM probe is fitted for various structural geometries. With this method, we can scan areas automatically for cracks.
CLEANING – GRINDING
Removal of rust and marine growth can be necessary to enable visual inspection or NDT. An electrical driven steel brush head is an effective method to clean steel surfaces and welds.
CUTTING – DRILLING
Hydraulic driven drill unit deployed to stress relieve identified material cracks. The unit is mounted with electromagnets and the drill head is tensioned with hydraulic force. The drill unit power is supplied via a SubC developed ROV mounted hydraulic power unit - HPU. The drill unit and process parameters are controlled via a programmable logic controller (PLC).
SEALING – PLUGGING
Hydraulic driven plugging unit to plug holes drilled in surfaces after stress relief of cracks. The unit is held in position with electromagnets and a SubC developed ROV mounted hydraulic power unit, that supplies the plug unit.
A hydraulic piston pulls a stainless steel mandrel that expands the rubber plug on the backside of the hole. When the plug is fully expanded a second hydraulic piston slides a lock pad in the mandrel, securing the plug firmly in position.
CLEANING – CAVITATION AND WATER JETTING
An ultra-cavitation cleaner (Cavi-Blaster) is an effective method to clean subsea structures from marine growth. The system operates at relatively low pressures of 1600 – 3500 psi. The special designed nozzle will make the water stream cavitate at this pressure. Therefore there is no harm to hard surfaces (steel, rubber, paint etc.), but marine growth is removed effectively. The Cavi-blaster is powered via a hydraulic hose by a gasoline powered high-pressure pump (220 bar) on the deck on the support vessel. The Cavi-blaster has a zero thrust design and will therefore have little effect on the ROV mobility.
NDT – CP READING
A Cathodic-protection (CP) probe that can serve as either a tip-contact or proximity probe can be utilized to measure the output of the subsea structures CP-system. The probe is attached to the ROV and a cable in the ROV umbilical will enable readout of the measurement in the ROV control centre. A wireless tip contact probe can also be mounted and readings is done visually via camera. To enable CP proximity readings on coated structures, a ground wire is to be attached to the steel structure in order to provide the needed electrical contact. The ground wire clamp is installed above surface. The Probe has dual silver/silver-chloride elements, which will give two independent readings and reveal a faulty element.
NDT – US THICKNESS READING
An ultrasonic gauge is a method for measuring the wall thickness of structures. The ultrasonic probe is mounted on an articulated support that allows 15 degrees of movement in both planes allowing automatic alignment to ensure a precise reading. The Surveyor will note the thickness readings (mm/m/s) from the ROV camera display.
SURVEY – 2D MULTIBEAM IMAGING SONAR
The Teledyne BlueView, M-series, 2D multibeam imaging sonar system is ideal for searching and navigating in low and zero visibility water. Furthermore, the sonar is perfect for inspection of cable/piping routing and scour protection. The combination of high-performance imaging capability and powerful software package makes the system extremely versatile for subsea ROV operation.
SURVEY – MECHANICAL MEASURING
Multiple survey probes are available to enable mechanical measuring/evaluation of subsea structures. The inventory comprise: anode depletion, marine growth thickness, curved/indented surfaces.