Tutorial 05: Rock Physics Modeling

Tutorial 05: Rock Physics Modeling#

Note

This tutorial is available as a Python script examples/05_rock_physics.py and an interactive Jupyter notebook examples/notebooks/05_rock_physics.ipynb.

This tutorial walks through a complete rock physics workflow: mineral mixing, dry-frame modeling, fluid substitution, and velocity computation.

What You Will Learn#

  • Compute effective mineral moduli with VRH

  • Model the dry rock frame with SoftSand

  • Perform fluid substitution using Gassmann

  • Compute Vp and Vs from elastic moduli

Workflow#

Minerals (K, G, rho)
       |
       v
   VRH averaging  -->  K_m, G_m
       |
       v
   SoftSand model  -->  K_dry, G_dry
       |
       v
   Gassmann  -->  K_sat, G_sat
       |
       v
   v_from_moduli  -->  Vp, Vs

Code#

from geobrain.physics.rock import VRH, SoftSand, Gassmann, DensityModel, v_from_moduli

vrh = VRH()
_, _, K_m = vrh(vol_fractions, K_minerals)
_, _, G_m = vrh(vol_fractions, G_minerals)

k_dry, g_dry = SoftSand()(K_m, G_m, porosity, 0.4, 7, pressure)
k_sat, g_sat = Gassmann()(k_dry, g_dry, K_m, K_fluid, porosity)
rho = DensityModel()(porosity, rho_mineral, rho_fluid)
vp, vs = v_from_moduli(k_sat, g_sat, rho)

Results#

../_images/05_rock_physics_fields.png

Fig. 44 Rock physics workflow: porosity to Vp, Vs, and density.#

../_images/05_crossplot.png

Fig. 45 Vp-porosity crossplot with rock physics model predictions.#

Full Example#

See examples/05_rock_physics.py.

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