Rock Physics: Seismic Reflections of Rock Properties

by Jack Dvorkin

Duration: Two days

Intended Audience: Intermediate level

Prerequisites (Knowledge/Experience/Education Required): Participants should at least have a B.Sc. in geophysics/geology with knowledge of principles of reflection, seismic prospecting, geology, and basic physics (elasticity and fluid flow).

Participants will learn the uses of rock physics in interpreting the elastic properties of earth, as sensed by seismic radiation, for lithology, fluid, and porosity determination. Presented are the basics of rock physics as well as applications of rock physics at various scales - from core to seismic. Real-time demos and exercises are given using Matlab-based applets.

Course Outline:

Basics of Rock Physics

  • Purpose of rock physics
  • Practical use of rock physics transforms in reservoir property mapping and synthetic seismic generation
  • Definitions and methods of rock physics
  • Elasticity
  • Static and dynamic moduli
  • Effect of pore fluid of rock's seismic properties
  • Fluid substitution
  • Importance of Vp/Vs and Poisson's ratio
  • Effects of frequency and saturation scales on rock's seismic properties

Applications of Rock Physics

  • Elastic properties of reservoir fluids
  • Velocity-porosity-mineralogy-texture
  • Effects of porosity, lithology, and texture on the elastic properties of sediments
  • Effects of diagenesis and grain sorting
  • Cementation
  • Rock physics models in high-porosity soft sediment
  • Rock physics of consolidated rock
  • Rock physics diagnostics and derivation of rock physics transforms from well log and core data

Special Topics

  • Attenuation
  • Scales of observations and experiments
  • Gas Hydrates

Learner Outcomes:

  1. Determine the level of rock physics required for a specific prospect evaluation. Are simple well-data-based cross-plots enough, or is involved mathematical rock physics modeling in order?
  2. Use simple ways of producing synthetic seismic signatures of reservoir and non-reservoir rocks for "what-if" scenarios for specific lithology, pore fluid, and geological settings.
  3. Handle methods of fluid substitution and quantify their relevance to the task at hand: prospect evaluation or production monitoring.
  4. Recognize various rock physics models that relate the elastic properties to porosity, lithology, and diagenetic history. Find an appropriate model for a specific project.
  5. Conduct rock physics diagnostics (i.e., establish a rock physics transform) based on well or laboratory data and consistent with geology.

Instructor Biography:
Jack Dvorkin