Paper submitted to 2nd EAGE/SBGF Conference on Deepwater Brazil Equatorial Margin, by Milos Cvetkovic (TGS)
Summary
The Equatorial Margin of Brazil presents a new frontier basin with high potential and prospectivity but faces challenges in prospects maturity and development. Besides the sheer size of the margins and the variability of geology and petroleum systems, year-long strong currents create particularly challenging and inefficient marine seismic programs. On top of that, environmental concerns present a limiting factor in productivity, often accounting for more than 20% of standby time and extending acquisition time, for large programs, by months.
New marine source technology, designed after the initial design of Wolfspar® (Dellinger et al., 2016), were primarily developed to provide better low frequencies to aid velocity model building. As these new sources have reduced sound levels at higher frequencies, they are considered more environmentally friendly and could decrease mammal exclusion zones and the overall environmental impact (Goertz et al., 2025). However, because these point sources are larger in volume, refill times can affect operational efficiency and compromise shot density, especially for streamer surveys, which remain the workhorse of Equatorial Margin exploration.
In this abstract, we present recent examples from both OBN and streamer acquisition done solely with the Gemini source (Brittan et al., 2020). Gemini is an extended-frequency source that provides enhanced low frequencies compared to conventional marine source arrays for velocity model building while maintaining higher frequency content for imaging. Across several projects, we have acquired data with an 8,000 cu. in. volume type in various streamer, sparse OBN, and, more recently, denser OBN configurations.
We believe extended-frequency source technology will become an integral part of new acquisition programs in deepwater Equatorial Margins, as it currently offers the best balance of bandwidth, data density, and operational efficiency.