The effect of compositional heterogeneity on poroelastic rock properties was treated by Brown and Korringa (1975). They found that the compressibility of a porous rock could be expressed as a function of the dry-rock compressibility, the pore-fluid compressibility, and two other parameters: the rock compressibility with constant differential stress, Ks, and the pore-space compressibility with constant differential stress, Kφ. Several workers have evaluated the Brown and Korringa parameters explicitly by modeling the rock as a composite made up of concentric spherical shells with different elastic properties. This model is generalized here to include shells that are locally transversely isotropic, with symmetry axis radial. That configuration is intended to roughly model clay platelets wrapped conformably around silt particles. An explicit expression is derived here for Ks by evaluating the model with two different pore fluids. The composite sphere model is then used to estimate Brown-Korringa parameters for clay-rich rocks. The models are applied to a geomechanical problem: computing the change in pore pressure due to erosional uplift of low-permeabilityrocks.
Presentation Date: Monday, October 12, 2020
Session Start Time: 1:50 PM
Presentation Time: 3:05 PM
Location: Poster Station 4
Presentation Type: Poster
