The Toolkit Map

Part 0: The Bridge

Learning objectives

Name the model families of rock physics and the kind of question each answers
Match a practical task to the family that owns it, and to the part of this course that builds it
Explain why bounds come first: they discipline every model that follows
Recognize when a task needs two families joined, a frame model plus fluid substitution

Six Families

Part 0 has made three claims: velocity is a model output, a reflection is an ambiguous sum, and every measurement lives at a frequency and a scale. The rest of the course is the toolkit that answers back, and it is smaller and better organized than the literature makes it look. There are six families. Bounds bracket what any mixture can possibly do, with no opinion about texture. Fluid models give the pore fluid its properties and swap it (Batzle-Wang, Gassmann). Contact models build sands from grains touching at points (Hertz-Mindlin and its soft-sand, stiff-sand, and cemented branches). Inclusion models build stiff rocks around pores with shapes (Kuster-Toksoz, DEM, Xu-White, and the carbonate pore-type extensions). Empirical relations fill gaps and tie everything to data (Han, the mudrock line, Greenberg-Castagna, Gardner, and calibration itself). And scale-and-time models reconcile the rulers: pressure and stress effects, Backus averaging for thin layers, dispersion between frequency bands.

How the Course Walks the Map

The order of the parts is the logic of the subject. Elasticity first (Part 1), because moduli are the currency everything else trades in. Bounds next (Part 2), because they discipline every model that follows: any prediction outside the bounds is wrong before it is tested, and any measurement outside them is misread. Fluids (Part 3) and Gassmann (Part 4) come before frame models because fluid substitution is the most-used move in the subject and the easiest to do carelessly. Then the two great frame families, contact (Part 5) and inclusion (Part 6); calibration to real data on the Ogbon-1 well (Part 7); pressure and time-lapse (Part 8); layers and frequency (Part 9); and the capstones, exam, and Lab (Parts 10 to 12) where the families stop being chapters and become a working kit.

Keep the map; the parts ahead fill it in. The ground floor is next: stress, strain, and the two moduli that carry the whole subject.

References

Mavko, G., Mukerji, T., & Dvorkin, J. (2009). The Rock Physics Handbook (2nd ed.). Cambridge University Press.
Simm, R., & Bacon, M. (2014). Seismic Amplitude: An Interpreter's Handbook. Cambridge University Press.