Seismic Multiple Removal Techniques: Past, Present and Future
|Dr Eric Verschuur (Delft University of Technology, Netherlands)|
|1 or 2 days|
|Geophysics – Seismic Processing|
|The EET 1 book (revised edition) is available in the EAGE Bookshop|
|5 or 10 CPD points|
3D DECONVOLUTION EXTRAPOLATION FILTERING FOURIER IMAGING INTERPOLATION INVERSION MIGRATION RADON TRANSFORM
A short version of this course has been recorded as an E-Lecture. Watching this video will give you a clear introduction of what the course is about and it will help you to prepare yourself if you are going to attend it!
The main objective of this course is to provide the audience with an overview of the techniques in seismic multiple removal, starting with the deconvolution-based methods from the 1960s, via the move-out discrimination techniques of the 1980s and ending up with wave-equation based methods from the 1990s and their 3D extensions as developed in the 2000s. Furthermore, the current challenges in multiple removal and their relation with seismic imaging and inversion are treated. A secondary objective is to discuss more general processing concepts such as high-resolution seismic data transforms (Fourier, Radon), adaptive filtering techniques, wave-equation based forward and inverse wave propagation and the processing of seismic data in different transform domains. For each method some brief description of the theory in terms of mathematics is given. However, the emphasis in this course is not to thoroughly treat the mathematics but to present some understanding of the workings of each method.
At the end of each lecture, a list of relevant articles in the open literature will be specified. The course is subdivided in 10 lectures, each of them being approximately 30-45 minutes. Within each lecture, examples of the described concepts on synthetic and field data will play an important role.
Lecture 1: Multiples ... what’s the problem?
- Classification of multiple reflections
- Characteristics of multiples
- Impact on seismic imaging and interpretation
- Categories of multiple removal methods
Lecture 2: Multiple removal based on move-out and dip discrimination
- Principle of multiple removal by move-out discrimination
- F-K and Radon transforms
- Multiple removal by filtering in the FK or Radon domain
- Towards high-resolution Radon transforms
- Limitations of multiple removal by move-out discrimination
- Multiple removal by target-oriented dip filtering
Lecture 3: Predictive deconvolution
- Convolution and correlation concept
- Designing adaptive filters by least-squares optimisation
- Predictive deconvolution basics
- Extending the predictive deconvolution concept
Lecture 4: Multiple removal by wave field extrapolation
- Forward and inverse wave field extrapolation
- Multiple prediction by wave field extrapolation
- Application in the wave number and linear Radon domain
Lecture 5: Principles of surface-related multiple elimination
- Derivation of SRME for the 1D situation
- Including the source characteristics
- Iterative implementation of SRME
- Formulation of SRME for the 2D and 3D situation
- Relation between multiple prediction and subtraction methods
Lecture 6: Practical considerations for surface-related multiple elimination
- Effect of missing data on SRME
- Interpolation of missing near offsets
- Application of SRME in different data domains
- Shallow water multiple removal strategy
Lecture 7: Adaptive subtraction of predicted multiples
- Least squares and L1-norm subtraction
- Pattern recognition and other multiple subtraction techniques
Lecture 8: Towards 3D multiple removal
- Multiples in complex 3D environments
- 3D SRME: theory and practice
- 3D SRME: solutions via data interpolation
Lecture 9: Internal multiple removal
- Internal multiple removal by move-out discrimination
- Extending the SRME concept to internal multiples
- Internal multiple removal by inverse scattering
Lecture 10: Removing or using multiples?
- Transforming multiple into primaries
- Estimation of primaries by sparse inversion
- Including multiples in the migration process
- Including multiples in the inversion process
For the 2-days course, especially the second part of the course, will be more elaborated with extra topics being:
- more elaborate discussion on adaptive subtraction techniques (Lecture 7)
- more extensive explanation on internal multiple removal (Lecture 9)
- including the recently developed EPSI (Estimation of Primaries by Spares Inversion) methodology (Lecture 10)
- including an extensive discussion on using surface multiples in Imaging (Lecture 10)
The target audience is composed of people involved in seismic processing, imaging and inversion. The mathematical content is kept to a minimum level with a strong link to the involved physical concepts, amplified by graphical illustrations. The audience is expected to have prior knowledge at a B.Sc./M.Sc. level on processing concepts such as convolution, correlation and Fourier transforms and some basic knowledge on wave theory.
Participants should have a basic knowledge of:
- Basic signal processing (convolution, correlation, Fourier transform);
- Basic seismic processing (preprocessing, imaging);
- Basic knowledge on the acoustic wave equation and wave propagation.
About the instructor
Dirk J. (Eric) Verschuur received his M.Sc. degree in 1986 and his Ph. D degree (honors) in 1991 from the Delft University of Technology (DUT), both in applied physics. From 1992 - 1997 he worked under a senior research fellowship from the Royal Dutch Academy of Art and Sciences (KNAW). In 1997 he became assistant professor and since 1999 he is an associate professor at the DUT at the laboratory of Acoustical Imaging and Sound Control. He is the project leader of the DELPHI research consortium in the area of Multiple Removal and Structural Imaging. His main interests are seismic modeling, processing and migration techniques. In 1997 he received SEG's J. Clarence Karcher award. He is a member of SEG and EAGE.
Explore other courses under this discipline:
Instructor: Mr Piet Gerritsma (Gerritsma Geophysical Training and Consultancy)
Seismic data processing can be characterized by the application of a sequence of processes where for each of these processes there are a number of different approaches. This course gives a comprehensive overview of the processes that are commonly applied in seismic data processing, both for land and marine seismic data, and discusses for each process the alternative implementations together with their inherent assumptions and strengths and weaknesses.
Instructor: Dr Ian Jones (ION)
The course will begin with a review of migration and then move-on to cover the motivations for building detailed velocity models, and briefly discuss the inherent limitations on our ability to build a detailed model. Current-day practice will be covered, exemplified via several case-studies and will end with a synopsis of the less well known and emerging techniques. Following the course, participants should understand how migration works, in terms of the approximations involved, and how this relates to the geology to be imaged, and also appreciate the limitations of current and future imaging and velocity estimation technology, so as to be able to decide what model building technique should be employed to image a given geological objective.
Instructor: Dr Vladimir Grechka (Marathon Oil Corporation)
Elastic anisotropy can strongly influence seismic data. This course discusses modeling, inversion and processing of seismic reflection and VSP data in the presence of anisotropy. The most critical step in extending the existing processing techniques to anisotropic media is to identify and estimate the medium parameters responsible for measured seismic signatures. The course emphasizes these parameters for vertical transverse isotropy – the anisotropic model usually associated with shales. Field-data examples illustrate the improvements in imaging achieved by anisotropic migration algorithms and the possibility of using anisotropy for lithology discrimination and fracture characterization.
Instructor: Dr Eric Verschuur (Delft University of Technology)
The main objective of this course is to provide the audience with an overview of the techniques in seismic multiple removal, starting with the deconvolution-based methods from the 1960s, via the move-out discrimination techniques of the 1980s and ending up with wave-equation based methods from the 1990s and their 3D extensions as developed in the 2000s. For each method some brief description of the theory in terms of mathematics is given. However, the emphasis in this course is not to thoroughly treat the mathematics but to present some understanding of the workings of each method.
Instructor: Dr Leon Thomsen (Delta Geophysics)
This course covers all areas of applied seismic anisotropy, with class exercises and ample time for full discussion. Because anisotropy is such a fundamental concept, it covers topics in seismic acquisition, processing, imaging and interpretation, all based on seismic rock physics.