Sea Technology

SEP 2017

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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Page 18 of 68

18 st / September 2017 Low-quality data will have huge impacts on the final results. This is state-of-the-art technology being used in a new application with enormous business potential. There are some technological and methodological issues that still need to be worked out, and we have yet to master the dif- ferent aspects of data processing, which, together with data acquisition, is the most critical step of the survey process for decommissioning projects, but the work is underway. ST Dr. Arthur Ayres Neto is a marine geologist and geophysicist with a Ph.D. in marine geophysics from the University of Kiel. After 17 years of working in the survey industry, since 2006, he has been a professor of engineering and envi- ronmental marine geophysics at Universidade Federal Fluminense. He worked as a consultant on this project. Geraldo Pinto Rodrigues is the chief executive and chief operating officer of CS- Sub. He is a geodesy and cartography technologist at the Brazilian Geography and Statistics Institute, and a geographer who graduated from the Universidade Federal Fluminense and Universidade Moacyr Bastos. He worked for 42 years on subsea engineering at Petrobras's geodesy division. Igor Drummond Alvarenga is the chief information officer of CSSub. He is a computer and information engineer who graduated from Universidade Federal do Rio de Janeiro, where he is now an M.S. student in electrical engineering. He developed data life cycle management, automated processing and quality control methodologies for this project. The combination of ultrahigh-resolution interferometric bathymetry with synthetic aperture sonar mosaics in a 3D visualization environment defines a change in paradigm for seabed inspections when complex problems are involved. The gain in productivity during acquisition (conservatively estimated at 40 percent) has relevant impacts on the overall project's budget and deadline. The possibility of analyzing the problems in a more complete way facilitates the plan- ning of future decisions with confidence, reducing the risks associated with decommissioning. Lessons Learned The use of an AUV and HISAS has proven to be the best- suited seabed inspection technology for decommissioning projects. The reduction in survey costs allied to a more com- plete visualization of subsea structures has clear advantages for planning and decision making. However, because of the very high resolution of the data acquired with HISAS, it is critical to have well-established acquisition protocols. As in any other hydrographic survey, the lack of quality control during data acquisition may have severe impact on the pro- cessing of the data, increasing time and costs for the project. 1953 County Street, East Taunton MA 02718 USA (800)822-4744 or (508)822-7330 Email: / 8" anchor chain - Low cost, single or dual frequency towfish - 500' (150m) depth capability - Simple to operate, "turn key" system - Up tp 2,000' (600m) range on each side - Displays sonar images on a laptop or tablet - Store files (XTF format) - In use by commercial dive companies worldwide with the help of a JW Fishers Side Scan Sonar! Remove the water "Using a 3D visualization environment, it is possible to gather the various stakeholders of the project, favoring interdisciplinarity, helping to clarify the uncertainties and enabling a better definition of the problems."

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