Page 334 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

326 CHAPTER 12 Sensor Theory
• Standard definition camera for documenting the job (or HD if the budget and principal investigator allows)
• CTD for sound velocity profiling (for acoustic positioning)
• USBL or LBL subsea acoustic positioning
12.3.6 Structural inspection
The inspection, repair, and maintenance (IRM—also termed IMR (depending upon the European or American accepted acronym)) is a critical job for the subsea industry as more and more offshore structures for oil and gas, as well as renewable energy generation, proliferate. Typical structures are placed with a life expectancy of at least 20 years. During that time, storms, oxidation, vessel traffic, and typical wear and tear require periodic inspection and maintenance.
A typical sensor load-out of a vehicle tasked for an IRM (IMR) project includes:
• Cathodic potential probe for measuring passive anode health
• HD and/or standard definition camera for documenting the inspection
• CTD for sound velocity profiling (for acoustic positioning)
• USBL or LBL subsea acoustic positioning (for pipeline or other subsea operations with no
exposed surface structure)
• Pipe tracker (for buried pipelines)
• Single or multibeam sonar for location of structure (and avoidance of hazards)
• NDT sensors for structural metal degradation testing
12.4 The future
As stated in the preamble to this chapter, sensor technology is where the real subsea technological developments are taking place. The future for sensor development in the medium term involves sensor fusion for automation of subsea functions (allowing for decoupling from the operator) as well as gains in sensor sensitivity for more accurate measurement of physical phenomena.
Speculation within the oil and gas industry (specifically, senior members of the Marine Technology Society) projects that the deepwater subsea field will be populated with autonomous vehicles docked to power stations that maintain an oil and gas production system to full ocean depth with minimal human intervention. As we move into the Arctic environment, such technology will become even more important. More discussion of this subject is available in Chapter 23.
Seventy-one percent of the earth’s surface is covered by water. There are vast lakes of liquid water underneath the ice caps of Greenland and Antarctica. There is speculation that there is more water on Jupiter’s moon Europa than there is on the earth. Water is the environment in which ROVs live. The future of our industry is limited only to our own imagination.