Page 557 - Petrophysics

524 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

(c) The fracture permeability is estimated from Eq. 8.38:

kf = 8.44 x lo-* x 178* x 1.5 = 39.6 Darcy

(d) The porosity partitioning coefficient and matrix porosity are
determined from Equations 8.3713 and 8.15:

Of
v=-=- 1.5 = 0.14
Ot 10.3

SPECIFIC AREA OF FRACTURES

Let S,, be the internal surface area per unit of pore volume, where the
surface area for n fractures is n(2wfL + 2hfL) = 2n(wf + hf)L, and the
pore volume is n(wfhfL), assuming the fracture provides all of the storage
and permeability. The specific surface area per unit pore volume is:

(8.41)

Using the same assumptions, the specific surface area per unit grain
volume is:

(8.42)

Multiplying and dividing by wfhf , and simplifying, yields:

2nwfhf
sgv = A(l-@)(d+;) (8.43)

Substituting for A from Equation 8.37 and simplifying results in:

(8.44)

The term l/hf is very small in comparison to l/wf because hf >> wf.
Thus equation 8.44 reduces to:

(8.45)