A new approach to compensate for illumination differences in 4D surveys with different individual acquisition geometries
Author: Didier Lecerf, Martin Besselievre
First Break - 1 February 2018
The authors demonstrate how the concept of Point Spread Functions can be successfully applied to time-lapse seismic when the respective acquisition geometries are very different and cannot be closely repeated.
Least-squares full-wavefield migration
Author: Shaoping Lu, Faqi Liu, Nizar Chemingui, Alejandro Valenciano, Andrew Long
The Leading Edge - 1 January 2018
We present a least-squares solution for depth migration of the full reflected wavefield. The algorithm combines primary and high-order reflected energy and significantly enhances the image illumination and resolution compared to those of conventional migration. Least-squares full-wavefield migration (LS-FWM) directly computes the earth's reflectivity, thereby avoiding crosstalk noise often observed in imaging using high-order reflections. Iteratively solving an inversion problem is computationally intensive and can suffer from instability issues; however, we develop an efficient least-squares procedure by combining a fast and accurate one-way wave-equation propagator with an effective linear inversion solver. An advanced regularization method is also employed to stabilize the inversion by controlling the over-fitting problem. Successful applications to both synthetic and field data examples demonstrate that LS-FWM greatly improves the imaging illumination and resolution compared to conventional migration.
Source and streamer towing strategies for improved efficiency, spatial sampling and near offset coverage
Author: Andrew Long
First Break - 1 November 2017
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.
The East Shetland Platform: Illuminating sub-BCU
Author: Stefano Patruno, Christine Roche
GeoExpro - 1 November 2017
New 3D data allows the true geological story of the Palaeozoic of the East Shetland Platform to be unravelled.
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
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
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
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
A new workflow assesses seismic image quality throughout the velocity model-building process.
Sea surface source-side static optimization for 4D seismic
Author: Simon Barnes, Paul Lecocq, Stephane Perrier, Mick Igoe
SEG - 1 September 2017
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.
High-performance computing for seismic imaging; from shoestrings to the cloud
Author: Sverre Brandsberg-Dahl
SEG - 1 September 2017