Seismic Diffractions - Modeling, Imaging and Applications
by Tijmen Jan Moser
*Please note: This course is not available for in-house training.
Duration: Two days
Intended Audience: Entry and Intermediate levels
Prerequisites (Knowledge/Experience/Education required): The prerequisites are a basic knowledge of seismic processing and imaging and an elementary mathematical background.
Course Summary:
There is a strong need in exploration and production for a direct method to detect and characterize fractures and other small-scale reservoir heterogeneities. It is precisely the seismic response from such small-scale structural and lithological elements in the subsurface that is encoded in diffractions. The diffraction component of the total wavefield is therefore the key element for higher resolution seismic analysis. Diffraction imaging, which allows the diffraction component of the wavefield to be visualized separately, is of great help to an interpreter. Structural features, such as small-scale faults pinchouts and fractures, can be more readily and reliably localized, identified and characterized on the diffraction images. The imaging of seismic diffractions is a rapidly emerging technology. The course will cover both the forward and inverse problems. The forward problem will extend from the discovery of the phenomenon of diffraction and the basic formulations of Fresnel and Kirchhoff to the evolution of modern seismic diffraction modeling. Diffraction imaging will be covered from the early works in the 1970s up to the present state of the art. Case studies will be presented covering examples from seismic exploration and other areas of geoscientific interest.
Course Outline:
1. Introduction
- Motivation, basic ideas and concepts
- Reflections versus diffractions
- Applications of diffractions
- Interpretation value
2. History
- Discovery and founding years (1650-1820): Grimaldi, Huygens, Newton, Young, Fresnel, Poisson, Arago
- Scalar diffraction: mathematical foundation – 19th century: Green, Helmholtz, Kirchhoff, Sommerfeld
- Towards Geometrical Theory of Diffraction – early 20th century: Maggi, Rubinowicz, Keller
- Towards Modern Theory: Trorey, Klem-Musatov
3. Diffraction Modeling
- Motivation, definitions, objectives
- Physical modeling
- Numerical modeling: integral methods, boundary layer methods, surface and caustic diffractions, finite differences, time-lapse, scattering methods
- Case study: Diffractions on Ground Penetrating Radar Data
- Case study: Diffraction response of Salt Diapirs
4. Diffraction Imaging in Time Domain
- Motivation, definitions, objectives
- Anatomy of diffractions
- Diffractions and standard processing
- Detection of diffractions
- Separation of diffractions
- Inversion of diffractions
- Imaging
- Common Reflection Surface/Multifocusing
- Focusing and velocity estimation
- Fracture detection
5. Diffraction Imaging in Depth Domain
- Motivation
- Velocity model considerations
- Illumination: edge and tip diffraction imaging
- Depth imaging: general principles
- Resolution and super-resolution
- Image processing and diffraction imaging
- Diffraction imaging by specularity suppression
- Applications: sandstone reservoirs, time-lapse, stratigraphic terminations against salt, carbonate reservoirs, shale resource plays, unconventional reservoirs
- Case study
Learner Outcomes:
The course will be clearly structured in topics and suptopics to be covered. At the end of each topic, a number of bullet points will summarize the items meant to be memorized and taken home by the learner. Interaction between the teacher and learner will be encouraged. The course material will be enlightened by out-of-the box examples demonstrating diffraction phenomena and supporting the theory. The target audience of the course are general geoscientists with a basic knowledge of seismic processing and imaging and an elementary mathematical background.
By the end of this course, the learner will:
- Have a detailed and up-to-date understanding of the physics of diffractions, diffraction modeling and imaging
- Be able to effectively communicate the key aspects of diffraction technology with other professionals
- Have a good understanding of the added value that seismic diffraction brings to current exploration and production projects
Instructor Biography:
Tijmen Jan Moser
