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[PDF] Method Changes the Way Marine Seismic Data are Acquired & Processed
Author: PGS
E&P Daily News - 15 October 2018PGS has recently completed a small scale seismic trial using eSeismic offshore Brazil. eSeismic involves the use of continuous source and receiver wavefields to fundamentally change the way that marine seismic data are acquired and processed. The results show a significant decrease in sound pressure levels meaning less environmental impact and sampling is improved without compromising efficiency.
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[PDF] Data Show Further Reservoir Potential along Brazil’s Equatorial Margin
Author: PGS
E&P Daily News - 16 October 2018Improved structural imaging of current discoveries and more confident mapping of reservoir distribution and variability are available with PGS fast-track prestack time migration output from the latest Potiguar-Aracati 3-D GeoStreamer survey. Current discoveries in the area exhibit elements of both structural and stratigraphic trapping, and the data indicate a number of undrilled analogous features on trend with the established discoveries. The amplitude versus offset fidelity and compliance delivered by GeoStreamer enables confident derisking of stratigraphic plays and prospects.
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[PDF] Côte d’Ivoire: Undiscovered Opportunities and New Data in Open Blocks
Author: Christine Roche
GeoExpro - 29 October 2018PGS modern broadband seismic coverage of Côte d’Ivoire now provides complete coverage of the area from source to sink.
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[PDF] Increasing Towed Streamer Survey Efficiency
Author: Andrew Long
Industry Insights - 20 August 2018The theme of value generation from different acquisition technologies in a climate of cost-saving pressure challenges for new marine exploration and 4D seismic acquisition shaped the agenda for the EAGE workshop on Marine Acquisition hosted in Oslo on August 22-24, 2018. This paper reviews the incremental improvements in survey efficiency that have taken place over the last couple of decades, and the step-change improvements that have recently emerged with the industry-wide use of both physical and virtual multi-source configurations.
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[PDF] Benefits of continuous source and receiver side wavefields
Author: Stian Hegna, Tilman Klüver, Jostein Lima
SEG - 14 October 2018In this paper, we describe a novel acquisition and processing method which makes use of continuous wavefields on both the source and receiver side to extract the response of the earth from marine seismic data. We will describe changes to the typical marine seismic acquisition method and outline the data processing methodology. Special emphasis is given to benefits gained from working with continuous wavefields in terms of improved acquisition efficiency and source side sampling in addition to reduced environmental footprint by lower sound levels.
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[PDF] Full Wavefield Migration by Inversion
Author: Shaoping Lu, Faqi Liu, Nizar Chemingui, Mikhail Orlovich
SEG - 14 October 2018Conventional seismic processing treats high-order reflected events as noise and tremendous efforts have been spent on their removal. Because of the extra interactions with the subsurface, multiples can be used as effective signal. When combined properly, the full wavefield including primaries and high-order reflections can significantly improve the illumination of the subsurface compared to primaries only. However, crosstalk has always been a major challenge for the joint imaging algorithm. In this paper, we present a Least-Squares inversion solution for depth imaging of the full recorded wavefield. The method effectively reduces the crosstalk and enhances the resolution by fully taking advantage of the extended illumination of all orders of reflections present in the data.
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[PDF] Improved operational efficiency using spread spectrum sweeps for marine vibrators
Author: Rune Tenghamn, Andrew Long, Christian Strand, Manuel Beitz,
SEG - 14 October 2018An encoded sweep strategy is described that enables efficient and flexible opportunities for towed marine vibrator seismic surveys capable of generating arbitrary signals with full phase control over the frequency of interest to seismic imaging. Continuous source operation with orthogonal signal sequences enable the use of many simultaneous marine vibrator units whilst towing at efficient vessel speed. Post-survey, the desired shot point interval for the optimized imaging of a particular depth range can be optimized by combining varying numbers of sub-sequences: shallow targets are imaged with short sub-sweeps and therefore short shot point interval, and deeper targets are imaged with longer sub-sweeps, longer shot point interval, and higher signal amplitude by virtue of longer sweeps. Overall, this strategy may enable less marine vibrator units by comparison to that required to achieve a given sound pressure level (SPL) using conventional sweep strategies, have significantly lower environmental impact than any air gun source design, and enable greatly improved operational efficiency.
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[PDF] Towed Streamer EM - Processing and Inversion
TechNote - 4 July 2017
Towed Streamer EM data is monitored on board the vessel in real time as it is acquired. Once a sail line is complete offline QC is conducted, including a 1D QC inversion of every shot acquired. The EM field deliverable is denoised, navigation merged data, and this is delivered to both the customer and PGS’ EM imaging team for 2.5D and 3D anisotropic inversion which is performed onshore.
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[PDF] Efficient broadband LS-WEM
Author: Shaoping Lu, Xiang Li, Alejandro Valenciano, Nizar Chemingui, Cheng Cheng
E&P Daily News - 14 June 2017A new methodology for LS-WEM is much less compute-intense.
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[PDF] Delivering increased CSEM data density
Author: Joshua May
Oilfield Technology - 1 May 2017Joshua May details a new approach to the acquisition and integration of complementary data which is designed to provide improved drilling success rates.