-
k = 1.2 x 10-15 x
3,
Log permeability and log diffusivity were shown vs. the porosity (Fig. F7) In the log permeability and porosity plot, two trends can be recognized (Fig. F7A): one for clay and one for hard rocks. Assuming parallel-sided or sphere-shaped pores, permeability is linear to the third power of porosity (Gueguen and Palciauskas, 1994). Poiseuill flow in cylindrical tubes leads to the relationship that permeability is linear with the square of porosity (Gueguen and Palciauskas, 1994). The fitting third-power law assumed between permeability and porosity of chalk, marl, chert, porcellanite, and basalt indicates the following relation:
3,
where k is permeability and is porosity. In the clayey samples, there is no suitable second- or third-power law for fitting the equation. The best-fit equation is as follows:
12.87.
Based on both the power law of permeability-porosity relationship and porosity-depth profile, the downhole-scale permeability profile can be reconstructed (Fig. F8). Porosities were measured using discrete samples or downhole logging (Accelerator Porosity Sonde [APS]). Because there was no porosity data in pelagic clay between 150 and 180 meters below seafloor (mbsf), permeability shows value are constant.
