80th EAGE Conference & Exhibition 2018
Opportunities presented by the energy transition
Surface and Internal Multiples - Lose them or Use them?
Friday 15 June 2018
|Title:||Surface and Internal Multiples - Lose them or Use them?|
E. Verschuur (Delft University of Technology)
In exploration seismology, most imaging and inversion approaches would not make use of multiple reflections, as such they have long been considered as noise, simply to be removed from the seismic data in a pre-processing step. However, an alternative view is that multiples should be included in imaging, since multiples, along with primary reflections, are an integral part of the physics of wave propagation that describes our seismic response.
In this context, our traditional imaging algorithms are too ‘simple’ to handle multiples properly. Although it would be desirable to include multiples in imaging, the conceptual and practical complexities associated with doing so raises key questions: for example, what would be the added value of leaving multiples in our signal and how can we take advantage of them in the imaging or inversion stage? Furthermore, for practical purposes, a distinction must be drawn between surface and internal multiples, both for removal as well as imaging algorithms. In recent years, it has been demonstrated that surface multiples, via a re-injection process of measured wavefields, can be used in imaging algorithms and can compensate for missing illumination from the primaries, due to the fact that spatial sampling in practical acquisition geometries is always coarse in some sense. However, this process introduces cross-talk in the imaging process. In parallel with recent progress on surface multiples, different algorithms have been proposed to properly handle internal multiples, some being model-driven while others fully data-driven. Are these approaches indeed “better”, e.g., leading to more reliable images with better SNR and resolution?
Given all these considerations, the aim of this workshop is to address the following questions/issues:
• Is there still room for multiple removal algorithms in the future?
• What are the (dis)advantages to keep multiples in the data for the imaging/inversion stage?
• Or should we first separate them from primaries and image them separately?
• What are the optimum strategies of using surface multiples in imaging/inversion?
• Does a dedicated removal/separation process provide more (adaptive) control on the result?
• And how about internal multiples? Is there a clear value coming out of novel methods?
• What is the meaning of primaries and internal multiples in thin beds? How thin is thin?
• Can a primary-only migration give a correct amplitude image? What about transmission?
• What is the role of the acquisition geometry on these considerations?
Who should attend?
• Geophysicists on wave propagation, multiple removal, imaging and inversion
• Audience from industry as well as academia
• Both experienced people as well as students who want to learn about this subject
||Oral Session 1: Multiples and their behaviour
|9:00||Understanding Multiples in Land Seismic Data
K. de Vos* et al (Shell)
|9:20||Attenuation of Near-surface Multiples on Land Seismic Data - Challenges, practical aspects and open issues
F.X. de Melo* (WesternGeco), C. Kostov (WesternGeco), A. El-Emam (Kuwait Oil Company), H. Bayri (Kuwait Oil Company)
|9:40||Seismic Interpretation when Short-period Internal Multiples are Present
F. Hilterman* (Geokinetics/Univ. of Houston), F. Nicholson (Beach Energy), M. Pareja (Geokinetics), C. Qi (Univ. of Houston)
|10:15||Coffee Break & Poster Session 1|
|Wave-equation Dispersion Inversion of Guided P-waves in a Waveguide of Arbitrary Geometry
J. Li (KAUST), S. Hanafy (KAUST), G. Schuster* (KAUST)
|Using Surface Multiples to Image Across Large Acquisition Gaps
A. Nath* (Delft Univ. of Technology), E. Verschuur (Delft Univ. of Technology)
|Marchenko Applications in the Data Domain
L. Zhang* (Delft Univ. of Technology), M. Staring (Delft Univ. of Technology), J. Brackenhoff (Delft Univ. of Technology)
|11:00||Oral session 2: Interbed multiples analysis and removal|
|11:00||Internal Multiple Modelling and Subtraction to Reduce the Risk in Quantitative Interpretation - An overview of the challenge, initial assessment, and way forward
A.C. Ramirez* (Equinor), E. Sadikhov (Equinor), L. W. Sigernes (Equinor)
|11:20||Internal Multiples Impact on Seismic Attenuation
A. Pica* (CGG)
|11:40||Making Acoustic and Elastic Internal Multiple Prediction Work Efficiently and without Artifacts
K. Innanen* (Univ. of Calgary)
|13:30||Oral session 3: Using surface multiples|
|13:30||Shallow Water Attenuation of Multiples by Inversion - Using multiples to make primaries to attenuate multiples
A. Kumar* (Down Under Geosolutions), G. Hampson (Down Under Geosolutions), T. Thompson (Down Under Geosolutions)
|13:50||Least-squares Full Wavefield Migration
S. Lu* (PGS)
|14:10||Utilizing Surface Multiples in Sparse Deepwater OBN Surveys
A. Mahdad* (Fairfield), P. Docherty (Fairfield), K. Craft (Fairfield)
|14:45||Coffee Break & Poster Session 2|
|Including Internal Multiples in Imaging Marine Data with Anisotropy - A joint migration inversion application
A. Alshuhail* (Saudi Aramco), E. Verschuur (Delft Univ. of Technology)
|Data Enhancement through Improved Attenuation of Internal Multiples
E. Sadikhov* (Equinor), A.C. Ramirez (Equinor), L.W. Sigernes (Equinor), S. Foss (Equinor)
|Focusing Conditions - A comparison between different Marchenko imaging strategies
G.A. Meles* (Delft Univ. of Technology), C. Reinicke (Delft Univ. of Technology), K. Wapenaar (Delft Univ. of Technology), J. Brackenhoff (Delft Univ. of Technology), J. Thorbecke (Delft Univ. of Technology)
|Towards the Prediction of Internal Multiples from Thin Layering by Marchenko
R. Hegge* (Saudi Aramco), G.A. Meles (Delft Univ. of Technology), K. Wapenaar (Delft Univ. of Technology)
|15:30||Oral session 4: Marchenko-based methods|
|15:30||A Single-sided Representation for the Homogeneous Green's Function, Accounting for all Multiples
K. Wapenaar* (Delft Univ. of Technology), J. Brackenhoff (Delft Univ. of Technology), J. Thorbecke (Delft Univ. of Technology), J. van der Neut (Delft Univ. of Technology), E. Slob (Delft Univ. of Technology)
|15:50||Overview of Marchenko Applications at the Edinburgh Interferometry Project
C. da Costa Filho* et al (Univ. of Edinburgh)
|16:10||An Overview of Marchenko-based Redatuming - Past, present, (and future)
M. Ravasi* (Equinor)
|16:30||Discussion and Conclusions
|17:00||End of Workshop|