Adding value to acoustic data sets in the offshore oil and gas industry by innovative processing and data integration techniques

Abstract

Among the acoustic methods used in ocean and marine geography investigations, the multibeam echo sounder was the product most affected by technological developments in the recent decades. With computers increasing their capabilities of processing, and new complex beam forming algorithms the acoustic signals returned now have excellent ranges and spatial resolutions. The possibility to digitally process these acoustic signals have allowed several other innovations such as the integration of various research methodologies into a single product and expanded the marine environment research possibilities by using the same mechanical and electronic sensor construction. The signals collected by multibeam echo sounders now allow identifying the facies analysis of the seabed, oceanographic features in the water column and even improvements in the sub-bottom profiler's performance. The hydrographic survey vessel FSSV Fugro Brasilis, provides a great case study of these echo sounders capabilities. With modern sensors, mounted in a gondola, 1 meter below the keel, away from the turbulence, aeration and laminar flow, minimizing noise and allowing the processing of low intensity return signals, this vessel exemplifies the installation of a complete system for technological hydrographic surveys down to 7.000m. The arrangement includes two multibeam echo sounders, a Kongsberg EM2040 for shallow water and an EM302 for deep waters, and also a sub-bottom profiler SBP300 sharing the multibeam reception transducers in order to observe the seabed sediment layers with maximum contrast and reflectivity. Part of the development and results evolution obtained passes through the data processing techniques applied to digital signals, which in this case use the processing software Fugro Starfix and Caris. Commercial programs like Caris HIPS & SIPS, make a more pragmatic approach. Naturally, they are in constant contact with the manufacturers from the most commercial relevant equipment and stay up to date in the digital signal processing techniques. Due to this monitoring of the new technologies, Caris HIPS & SIPS are the most suitable software for processing the water column and backscatter data. With the advance of technology, the number of products increases, not only restricted to the accurate achievement of bathymetry, but also enabling the integration of different techniques in order to provide more information in a single product. One of the ways found to increase the investigations quality at sea is processing of the water column data integrated with the bathymetry. This technique enables the research of outline structures in the ocean environment, such as hot springs and gas exudation. The combination of these bathymetric, facies analysis and seabed characterization information through the backscatter and high acoustic contrast aquatic structures allows a presentation of integrated and complete results. With these new technological developments, understanding of oceanic processes is more detailed, supporting academic research and engineering works.