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[PDF] Subsalt exploration in shallow waters of the Republic of Congo
Author: Pierre Le Barbanchon, Tony Martin, Mark Martin, Louis Andzouono, Jean Pierre Saba, Alain Richard N’Gouala Nzoussi
First Break - 1 March 2019The authors reveal new subsalt hydrocarbon potential on the Congo Shelf using modern broadband imaging techniques applied to multi-vintage seismic data.
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[PDF] Automatic QC of denoise processing using a machine learning classification
Author: Maiza Bekara, Anthony Day
First Break - 2 September 2019The authors describe a new approach to automate the quality control of denoise processes in seismic data processing using machine learning.
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[PDF] Optimizing performance of data processing
Author: Samuel Brown, Tony Martin
First Break - 1 December 2019The authors describe the process of optimizing data throughput, to reduce turnaround and enable both full automation and interactivity of geophysical tasks in an architecture agnostic environment.
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[PDF] Modern seismic data reveals potential for a deeper play in North Madura, East Java, Indonesia
Author: Maz Farouki, Andy Bromley, David Cavalin
APGCE - 29 October 2019The East Java Basin is a prolific hydrocarbon province in Indonesia in which exploration plays have typically targeted the pinnacle reefs of the Oligocene-Miocene Kujung carbonates. Robust imaging of the deeper section however has historically been challenged due in part to the limited bandwidth of conventional seismic data. A further challenge arises from the imaging artifacts introduced at the overlying Wonocolo carbonate platform, where the slow velocities of deep channel incisions are in strong contrast with the fast carbonate velocity. Prestack depth migration can be used to address this issue, but requires a velocity model with sufficiently high spatial and temporal resolution to precisely capture such velocity variations. To this aim, Full Waveform Inversion is used in the velocity model building. Whereas legacy data in the basin has struggled to image deeper than the Kujung level, seismic acquisition and imaging methods are now providing data with greater bandwidth and deeper penetration of signal. In Madura, the deeper Eocene Ngimbang formation as well as basement are now much better resolved, opening up the potential play in the Ngimbang clastics.
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[PDF] Application of Full Waveform Inversion to resolve an eroded shallow carbonate platform, North Madura, East Java, Indonesia
Author: David Cavalin, Nurrul Ismail, Tom Paten, Kola Agbebi, Dave Lim
IPA - 2 September 2019Proven plays in North Madura have been identified in the Miocene carbonate and syn-rift Eocene clastic systems. 3D broadband seismic data was acquired in order to obtain higher resolution and deeper imaging of potential prospects and leads within these systems.
Besides improving resolution, penetration, imaging and seismic attributes, broadband data has another major advantage; it allows the low frequencies of the recorded data to drive a more complex velocity model update technique: Full Waveform Inversion (FWI).
Standard traveltime reflection tomography techniques provide long to mid wavelength velocity updates but generally fail in updating shallow water environments while giving limited resolution in the rest of the velocity model. However, a more accurate velocity model is needed to correct rapid vertical and lateral velocity heterogeneities. Small-scale velocity anomalies in this survey include gas bearing river channels, whereas eroded shallow carbonate platforms present additional challenges related to structural distortions observed on the time domain outputs. Such velocity anomalies must be resolved prior to imaging the deeper section.
FWI operates by minimizing residuals calculated between recorded shot records and modeled shots, within a certain frequency band. An iterative approach was used to update the velocity model starting with low frequencies available from the broadband seismic data. Using the lowest possible frequency data, containing coherent signal, minimizes the risk of cycle skipping thus allowing the FWI update to start from a benign velocity model. The successive passes of FWI introduced details into the velocity model conforming to the geological challenges identified at the beginning of the project.
Combining both broadband data and FWI velocity model building (VMB) is key in correcting for structural distortion and amplitude dimming particularly associated with shallow velocity anomalies. This methodology allowed us to confidently position in depth the potential plays and leads affected by velocity anomalies in the shallower section.
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[PDF] Enhanced subsurface illumination from separated wavefield imaging
Author: Shaoping Lu, Dan Whitmore, Alejandro Valenciano, Nizar Chemingui
First Break - 1 November 2014The authors present applications of separated wavefield imaging to a deepwater wide-azimuth survey in the Gulf of Mexico and to a narrow azimuth data set from offshore Malaysia.
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[PDF] An innovative approach automation for velocity model building
Author: Tony Martin, Marcus Bell
First Break - 3 June 2019Tony Martin and Marcus Bell describe the use of a Monte Carlo simulation, enabling multiple realizations of the solution in order to derive estimates of the uncertainty of an individual model, as well as drive velocity model building in an automated fashion.
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[PDF] Towed Streamer EM – reliable recovery of sub-surface resistivity
Author: Allan McKay, Johan Mattsson, Zhijun Du
First Break - 1 April 2015The authors present a seismically guided inversion and illustrate the workflow of the data integration, which remains driven purely by the seismic and EM data.
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[PDF] 2020_First-Break_Klochikhina-et-al_Leveraging_deep_learning_for_seismic_image_denoising.pdf
1 January 0001
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[PDF] Intra-Chalk Porosity Variations in Norway-Danish Central Graben: Integrated Mapping Using Broadband Elastic Attributes
Author: Noémie Pernin, Tim Bird, Cyrille Reiser
EAGE - 4 June 2018Understanding the influence of porosity on elastic properties through rock physics analysis is essential in seismic reservoir characterisation and key in the context of the chalk play. It is known that acoustic impedance is strongly correlated with porosity in carbonates but also that the chalk properties can vary widely creating intra-chalk layers of varying reservoir quality. This integrated study shows how reliable broadband relative elastic attributes tie at the wells and are able to map lateral and vertical changes of porosity within the Chalk interval in the Norwegian and Danish North Sea Central Graben.