Technical Library

  • Source and streamer towing strategies for improved efficiency, spatial sampling and near offset coverage

    Author: Andrew Long
    First Break - 1 November 2017

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    The author presents a study of the fundamental relationships between cross-line source configurations and towed streamer survey efficiency and spatial sampling using a set of robust geometric relationships.

  • Quantitative interpretation sensitivity to angle and frequency-dependent pre-stack time shift, amplitude and phase perturbations

    Author: Matthew Whaley, Cyrille Reiser, Andrew Long
    First Break - 1 October 2017

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    Matthew Whaley, Cyrille Reiser and Andrew Long present a modelling study to quantify how angle-dependent time shifts, angle-dependent frequency variations, or frequency-dependent phase errors can impact the recovery of elastic impedance attributes using pre-stack simultaneous seismic inversion.

  • Project highlights new prospectivity in the Santos Basin

    E&P Daily News - 27 September 2017

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    The rejuvenated Santos Vision regional dataset is ideal for pre-salt exploration in Brazil. This new product covers an area of 35 000 sq. km and has been reprocessed with our most advanced imaging solutions, including least-squares, RTM and Q-Kirchhoff.

  • Reducing FWI dependence on long offsets for deeper velocity model updates

    E&P Daily News - 26 September 2017

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    Reflections rather than diving waves and refractions push FWI deeper

  • Rapid interactive RTM scenario testing improves image quality beneath complex salt

    E&P Daily News - 25 September 2017

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    A new workflow assesses seismic image quality throughout the velocity model-building process.

  • Total hydrocarbon volume in place: improved reservoir characterization from integration of towed-streamer EM and dual-sensor broadband seismic data

    Author: Zhijun Du, Ghazwan Namo, Joshua May, Cyrille Reiser, Jonathan Midgley
    First Break - 1 September 2017

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    The authors present a geophysical reservoir characterization workflow that seeks to integrate elastic and electric attributes derived from inversion of seismic and CSEM data.

  • Sea surface source-side static optimization for 4D seismic

    Author: Simon Barnes, Paul Lecocq, Stephane Perrier, Mick Igoe
    SEG - 1 September 2017

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    Management of producing fields can be enhanced by effective seismic reservoir monitoring. Improved repeatability of 4D monitor surveys can be achieved by applying deghosting and datuming via seismic wavefield separation. By also correcting for the variable distance of the source above the seabed caused by the sea state will increase 4D repeatability further.

  • Broadband Least-Squares Wave-Equation Migration

    Author: Shaoping Lu, Xiang Li, Alejandro Valenciano, Nizar Chemingui, Cheng Cheng
    SEG - 1 September 2017

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    In general, Least-Squares Migration (LSM) can produce images corrected for overburden effects, variations in illumination, and incomplete acquisition geometry. The modeling engine of our LSM implementation consists of a visco-acoustic anisotropic one-way wave-equation extrapolator. It has the advantage of efficiently propagating high-frequency seismic data using high-resolution earth models (e.g. derived from Full Waveform Inversion). Applications to synthetic and field data examples (from the Gulf of Mexico and the North Sea) consistently delivered higher resolution images with better amplitude balance when compared to standard seismic migration

  • Full waveform inversion with an exponentially-encoded optimal transport norm

    Author: Lingyun Qiu, Jaime Ramos-Martínez, Alejandro Valenciano, Yunan Yang, Björn Engquist
    SEG - 1 September 2017

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    Full waveform inversion (FWI) with 𝐿𝐿2norm objective function often suffers from cycle skipping that causes the solution to be trapped in a local minimum, usually far from the true model. We introduce a new norm based on the optimal transport theory for measuring the data mismatch to overcome this problem. The new solution uses an exponential encoding scheme and enhances the phase information when compared with the conventional 𝐿𝐿2norm. The adjoint source is calculated trace-wise based on the 1D Wasserstein distance. It uses an explicit solution of the optimal transport over the real line. It results in an efficient implementation with a computational complexity of the adjoint source proportional to the number of shots, receivers and the length of recording time. We demonstrate the effectiveness of our solution by using the Marmousi model. A second example, using the BP 2004 velocity benchmark model, illustrates the benefit of the combination of the new norm and Total Variation (TV) regularization.

  • Strategies for High Resolution Towed Streamer Acquisition and Imaging of Shallow Targets

    Author: Martin Widmaier, David O’Dowd, Carine Delarue
    SEG - 1 September 2017

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    The challenging combination of shallow water and shallow exploration targets in larger parts of the Barents Sea cannot be sufficiently addressed by the application of conventional marine seismic acquisition and imaging techniques. High resolution data, proper spatial sampling, as well as near offset/near angle information are key elements for imaging and quantitative interpretation. We first discuss several existing acquisition and imaging technologies that have been applied in the area, including standard towed streamer surveys, p-cable, and imaging with separated wavefields. We then introduce novel acquisition concepts. The innovative combination of high density seismic and wider towing of sources can be a cost-effective approach to acquire high quality seismic data with significantly improved near offset coverage and denser spatial sampling for shallow imaging. These configurations can be tuned such that both shallow and deeper targets are optimally imaged.