Attenuation: Challenges in Modelling and Imaging at the Exploration Scale

Workshop 1:
Sunday, 2 June
Lecture Room:1
Conveners:
Hervé Chauris (MINES ParisTech)
Fatiha Gamar-Sadat (CGG)
René-Edouard Plessix (Shell)
Yanghua Wang (Imperial College London)

Description:

Seismic attenuation is a very useful property to detect the presence of fluids in seismic data. The techniques for modelling attenuation as well as the strategies for estimating attenuation are still largely evolving. The objective of the workshop is to review the recent advances in this field at the exploration scale and to invite researchers from both the modelling and imaging sides.

The three main aspects addressed during the workshop could be organised as follows:

  1. How to model attenuation? Behind the generic Q-model, there are a number of different theoretical and physical approaches to model the effect of attenuation. Is there a consensus for applications at the exploration scale? What should be the dependency over frequency? Is there any consistency between attenuation at the lab scale and at 10 Hz? Should we prefer the time or frequency domains for modelling waves in visco-acoustic / visco-elastic media? 

  2. For the inversion side to retrieve attenuation, what is the input data (e.g. amplitude decay, frequency shift, full wave field recorded at the receiver position)? What are the associated objective functions (e.g. data domain least-squares misfit, image domain methods, …)? What are the model parameters (e.g. can we neglect Qs if we consider surface waves)? Attenuation is not the only model parameter, and Vp should also be estimated. How do we handle the multi-parameter inversion and ambiguity between velocity and attenuation perturbations? Are there some recommendations to split the model into a macro-model and a reflectivity model and to estimate the two models in a tomography and migration mode, respectively? Is there a gap like for seismic velocities at intermediate scale? Can we distinguish between intrinsic and scattering attenuation?

  3. Finally, we would like to invite people to present case studies and to discuss the practical aspects, including the pre-processing steps for successful attenuation estimations.We would like to conclude the workshop on the value of attenuation and on the new acquisition techniques to be developed in the future for facilitating the estimation of attenuation.

Workshop format: 

Presentations followed by discussions. 

Who should attend: 

Researchers interested in attenuation modelling and in seismic imaging

Workshop Programme:

Introduction
09:00 Introduction
Section 1– Overview and Mechanisms
09:10 A Brief Overview on Seismic Attenuation
J. Carcione* (OGS)
09:40 Seismic Attenuation Mechanisms in Fractured Fluid Saturated Media – Numerical and field examples
E. Caspari* (Univ. of Lausanne), N.D. Barbosa (Univ. of Lausanne/Univ. of Geneva), M. Novikov (Novosibirsk State Univ.), V. Lisitsa (Novosibirsk State Univ.), J. Hunziker (Univ. of Lausanne), B. Quintal (Univ. of Lausanne), G. Rubino (Centro Atmico Bariloche - CNEA), & K. Holliger (Univ. of Lausanne)
10:00 Use of the General Fractional Zener Model to Represent Attenuation in Poro-viscoelastic Numerical Modeling
X. Liu (King Fahd Univ. Of Petroleum And Minerals) and S. Greenhalgh* (King Fahd Univ. Of Petroleum And Minerals)
10:20 Discussion
10:35 Coffee break 
Section 2 - Experimental Investigation and Historical Perspectives
10:50 Dispersion and Attenuation of Wave Velocity in Fluid-saturated Rocks: Experimental investigations
J. Fortin (Ecole Normale Superieure) & J. Borgomano* (Ecole Normale Superieure)
11:10 Attenuation from Passive Seismic Monitoring
M. Wcislo* (Charles Univ. in Prague) & L. Eisner (Seismik Ltd.)
11:30 Q Compensation: from nice to have to Mandatory but…
P. Charron* (Total), B. Duquet (Total), C. Agut (Total) & A. Lafram (Total)
11:50 Q-Tomography: status and challenges
F. Gamar-Sadat* (CGG), A. Pintus (CGG), P. Guillaume (CGG) & A. Wright (CGG)
12:10 Discussion
12:25 Lunch break
Section 3 – Modelling and Imaging
13:25 Introduction
13:30 Viscoelastic Full Waveform Inversion of Wide-angle Data: Application to ultra-long offset data from Mentawai Basin, Indonesia
S. Singh* (IPGP), T. Belahi (IPGP) & N. Fuji (IPGP)
13:50 Effect and Reconstruction of Attenuation in Acoustic FWI - Method and field data application
N. Kamath* (Univ. Of Grenoble Alps), R. Brossier (Univ. Of Grenoble Alps), L. Metivier (Univ. Of Grenoble Alps) & P. Yang (Electromagnetic Geoservices ASA)
14:10 A Hybrid Inversion Strategy for Visco-acoustic Full Waveform Inversion: Application to the Marmousi model
H. Jiang* (Ecole des MINES de Paris) & H. Chauris (Ecole des MINES de Paris)
14:30 Joint Estimation of Velocity and Attenuation by Frequency-domain TV-regularized Wavefield Reconstruction Inversion
H. Aghamiry* (Univ. Côte d'Azur/ Univ. of Teheran), A. Gholami (Univ. Côte d'Azur) & S. Operto (Univ. Côte d'Azur)
14:50 Discussion
15:05 Coffee break
Section 4 – Case studies
15:20 Accounting for Heterogeneous Attenuation in Full-wavefield Inversion
M. Lacasse* (ExxonMobil), H. Denli (ExxonMobil), L. White (ExxonMobil), V. Gudipati (ExxonMobil), S. Lee (ExxonMobil), & S. Tan (ExxonMobil)
15:40 Reviewing the Impact of Attenuation Under Thick Karst and the Implications for Survey Design and Processing
T. Manning* (BP), S. Wolfarth (BP), B. Priyambodo (BP), & T. Septyana (BP)
16:00 Integrated Visco-acoustic Model Building: A case study illustrating the challenges and benefits for large scale exploration
T. Martin* (PGS), M. Barbaray (PGS), G. Venfield (PGS), & V. Chavda (PGS)
16:20 Integrated Time-lapse Analysis of Shallow Gas Movement: Mapping attenuation observations into pore pressure and saturation changes
H. Dinh* (Univ. of Alberta), M. Van der Baan (NTNU), & M. Landro (NTNU)
16:50 Discussion
Conclusions
17:05 Final Discussion
17:30End of Workshop
*Presenter

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