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ager, Earth Data at Viridien. “The most changed the in? ll well locations and recently awarded storage licenses in- improved their production and re- clude a commitment from developers serve estimates.” to reprocess legacy seismic data.” Krishna expects new streamer acquisi-

New oil and gas discoveries are tion to decrease in volume and go more also sparking interest in legacy data. hybrid (Ocean Bottom Node (OBN) + 3400-OTS

The play-opening giant discover- streamer data) or fully OBN to provide ies of Baleine and Murene-1 (Calao) enhanced reservoir imaging. offshore Tano Basin, Côte d’Ivoire, OBN data is generally considered

SUB-BOTTOM have reinvigorated exploration in the better than streamer data because it

PROFILER equatorial margin of Africa, and in provides a much richer subsurface 2024, Viridien merged and re-imaged image due to its ability to capture a seamless and contiguous volume of a wider range of seismic wave ar- 6,434 km2 of 3D multi-client seismic rivals, including longer offsets, full data in the basin. azimuthal coverage and better low-

The data included four separate sur- frequency information.

veys acquired over multiple blocks be- Seismic imaging is constantly ad- tween 2000 and 2014 from the shelf vancing. Viridien uses full-waveform to the outer slope domain. These four inversion (FWI) algorithms that surveys with differing cable depths produce highly detailed, data-driv- and streamer pro? les, along with sig- en models of subsurface velocity, ni? cant variations in legacy process- absorption (Q) and re? ectivity by ing work? ows, were merged to create minimizing the difference between a contiguous seismic volume. The new observed and modeled seismic wave- re-imaging was undertaken from ? eld forms. FWI is now the industry stan- tapes using proprietary technologies dard for velocity model building and such as time-lag full-waveform inver- has been applied to legacy and new sion velocity model building. seismic survey con? gurations.

In the North Sea, Viridien recent- Time-lag FWI (TLFWI) is a pro- ly reprocessed multi-client seismic prietary Viridien technology that ad- streamer data to create value for cli- dresses issues which plagued earlier ? Compact Size: 77 x 33 cm ents evaluating the Central North Sea FWI algorithms, such as cycle-skip- ? Light Weight: 21 or 26 kg and the Southern North Sea. “We were ping issues related to an inaccurate ? Impactful: Up to 80m able to enhance the legacy streamer initial model, amplitude mismatches penetration data with signi? cant uplift to the ? nal between observed and modeled seis- images,” said Hari Krishna, Director mic and a poor low-frequency signal- ? Wideband CHIRP: Up to 4 cm resolution

Europe, North Africa & Middle East, to-noise ratio of ? eld data. TLFWI

Earth Data, Viridien. has been highly successful in velocity ? Loaded: Pitch, roll, heave

Clients found the new depth models model building for complex geologi- and depth sensors to be accurate within 1% of the target cal settings around the world, includ- ? Versatile: Ideal for small boat depth for exploration wells, enabling ing sub-salt, carbonates, thrust belts and USV installations them to place their wells optimally. and shallow gas. It is often used in ? Proven: For a wide variety “All of our reprocessing projects in conjunction with OBN data sets and of applications the past 5-6 years have been very well as a way of improving the image on funded. In our estimates, more than legacy seismic data.

70% of active blocks in the Central FWI Imaging takes the process a

North Sea use Viridien data as their step further by outputting an image primary database. of subsurface re? ectivity directly, “In the Southern North Sea, our often providing a superior result in reprocessing of streamer data from complex areas where migration algo- 2014 fundamentally changed the res- rithms struggle.

ervoir model. As a result, the client “TLFWI and FWI Imaging, whether www.marinetechnologynews.com

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