log (k) = log (ko)+pn (2)
where ko is the projected permeability at zero porosity and yp is a parameter describing the
rate of permeability change with porosity.
With respect to Neuzil's (1994) compilation of permeability data for argillaceous
sediments, most of the Nankai core permeability values fall in the central portion of the
data range (Figure 3-4), while a few permeability values with porosities between 0.2 and
0.3 fall closer to the higher-permeability margin of the data range. The measured
permeability values are best fit by the following relationship:
log (k)= -19.82+5.39n (3)
-14
-16
-18
0 -20
-22 -
0 0.2 0.4 0.6 0.8 1
Porosity
Figure 3-4. Permeability data measured for samples from ODP Leg 190 (solid diamonds)
superimposed on a large-scale permeability versus porosity outline for
argillaceous sediments compiled by Neuzil (1994). Solid line represents the
best-fit line for the measured permeabilities. The dashed line with + mark
represents the permeability-porosity relationship for the lower range of
measured permeability values. The shaded area represents the range of
permeability-porosity relationships established by Saffer and Bekins (1998),
with the dashed line (log (k)=-20+5.25n) indicating a mid-range value.
The permeability-porosity relationship obtained from this study has a similar slope
to the relationships used by Saffer and Bekins (1998) (log (k) = -20+5.25 n) but predicts
slightly higher permeability values (Figure 3-4). The lower range of permeability values